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- CHAPTER -1 INTRODUCTION ABOUT CRANKSHAFT
- ABSTRACT Crankshaft is a large component with a complex geometry in the engine, which converts the reciprocating displacement of the piston to a rotary motion with a four link mechanism. Since the crankshaft experiences a large number of load cycles during its service life, fatigue performance and durability of this component has to be considered in the design process. Design developments have always been an important issue in the crankshaft production industry, in order to manufacture a less expensive component with the minimum weight possible and proper fatigue strength and other functional requirements. These improvements result in lighter and smaller engines with better fuel efficiency and higher power output. Crankshaft must be strong enough to take the downward force of the power stroke without excessive bending. This project deals with the problem occurred in single cylinder engine crank shaft. It consists of static structural and modal analysis of single cylinder engine crank shaft. It identifies and solves the problem by using the modelling and simulation techniques. The topic was chosen because of increasing interest in higher payloads, lower weight, higher efficiency and shorter load cycles in crankshaft. The main work was to model the crank shaft with dimensions and then simulate the crank shaft for static structural and modal analysis. The modelling software used is Pro-e/creo-2 for modelling the crank shaft. The analysis software ANSYS will be used for structural and modal analysis of crank shaft for future work. The material for crank shaft is Cast Iron and other alternate materials on which analysis will be done are SAE 1045, SAE 1137,and EN9. The objectives involve modelling and analysis of crank shaft, so as to identify the effect of stresses on crank shaft, to compare various materials and to provide possible solution.
- CRANKSHAFT Crankshaft is a large component with a complex geometry in the engine, which converts the reciprocating displacement of the piston to a rotary motion with a four link mechanism. Since the crankshaft experiences a large number of load cycles during its service life, fatigue performance and durability of this component has to be considered in the design process. Design developments have always been an important issue in the crankshaft production industry, in order to manufacture a less expensive component with the minimum weight possible and proper fatigue strength and other functional requirements. These improvements result in lighter and smaller engines with better fuel efficiency and higher power output. Crankshaft must be strong enough to take the downward force of the power stroke without excessive bending. So the reliability and life of the internal combustion engine depend on the strength of the crankshaft largely. And as the engine runs, the power impulses hit the crankshaft in one place and then another. A single-cylinder engine is a basic piston engine configuration of an internal combustion engine. It is often seen on motorcycles, auto rickshaws, motor scooters, mopeds, dirt bikes, go-karts, radio-controlled models, and has many uses in portable tools and garden machinery. It has been used in automobiles and tractors. Single-cylinder engines are simple and compact, and will often deliver the maximum power possible within a given envelope. Cooling is simpler than with multiple cylinders, potentially saving further weight, especially if air cooling can be used.
- Single-cylinder engines require more flywheel effect than multi-cylinder engines, and the rotating mass is relatively large, restricting acceleration and sharp changes of speed. In the basic arrangement they are prone to vibration - though in some cases it may be possible to control this with balance shafts. A variation known as the split-single makes use of two pistons which share a single combustion chamber. Single-cylinder engines are simple and economical in construction. The vibration they generate is acceptable in many applications, while less acceptable in others. Counterbalance shafts and counterweights can be fitted but such complexities tend to counter the previously listed advantages. Components such as the crankshaft of a single-cylinder engine have to be nearly as strong as that in a multi-cylinder engine of the same capacity per cylinder, meaning that some parts are effectively four times heavier than they need to be for the total displacement of the engine. The single-cylinder engine will almost inevitably develop a lower power-to-weight ratio than a multi-cylinder engine of similar technology. This can be a disadvantage in mobile operations, although it is of little significance in others and in most stationary applications.
- Uses: A single-cylinder Villiers engine in the engine bay of a 1959 Bond Minicar Motorbike Horex "Regina" with one-cylinder-four-stroke-engine Early motorcycles, automobiles and other applications such as marine engines all tended to be single-cylinder. The configuration remains in widespread use in Auto rickshaws, motor scooters, mopeds, dirt bikes, go-karts, radio-controlled models and is almost exclusively used in portable tools, along with garden machinery such as lawn mowers. The bestselling motor vehicle of the world, the Honda Super Cub, has a very fuel-efficient 49 cc single-cylinder engine and big-diameter 17-inch wheels. Some motorcycles with strong single-cylinder engines are available today. There are sport bikes like the KTM 690 Duke R[1] which has 70 hp 690 cc single-cylinder engine and reaches 125 mph (200 km/h) with a curb
- weight of only 150 kg, dual-sport motorcycles like the BMW G650GS, as well as classics like the Royal Enfield 500 Bullet with a long-stroke single-cylinder engine.[2] Construction Crankshafts can be monolithic (made in a single piece) or assembled from several pieces. Monolithic crankshafts are most common, but some smaller and larger engines use assembled crankshafts. Forging and casting
- Forged Crankshaft Crankshafts can be forged from a steel bar usually through roll forging or cast in ductile steel. Today more and more manufacturers tend to favour the use of forged crankshafts due to their lighter weight, more compact dimensions and better inherent damping. With forged crankshafts, vanadium micro alloyed steels are mostly used as these steels can be air cooled after reaching high strengths without additional heat treatment, with exception to the surface hardening of the bearing surfaces. The low alloy content also makes the material cheaper than high alloy steels. Carbon steels are also used, but these require additional heat treatment to reach the desired properties. Iron crankshafts are today mostly found in cheaper production engines (such as those found in the Ford Focus diesel engines) where the loads are lower. Some engines also use cast iron crankshafts for low output versions while the more expensive high output version use forged steel. Machining Crankshafts canalso be machined out of a billet, often a bar of high quality vacuum remelted steel. Though the fibre flow (local in homogeneities of the material's chemical composition generated during casting) doesn’t follow the shape of the crankshaft (which is undesirable), this is usually not a problem since higher quality steels, which normally are difficult to forge, can be used. These crankshafts tend to be very expensive due to the large amount of material that must be removed with lathes and milling machines, the high material cost, and the additional heat treatment required. However, since no expensive tooling is needed, this production method allows small production runs without high costs. In an effort to reduce costs, used crankshafts may also be machined. A good core may often be easily reconditioned by a crankshaft grinding [21] process. Severely damaged crankshafts may also
- be repaired with a welding operation, prior to grinding, that utilizes a submerged arc welding machine. To accommodate the smaller journal diameters a ground crankshaft has, and possibly an over-sized thrust dimension, undersize engine bearings are used to allow for precise clearances during operation. Fatigue strength The fatigue strength of crankshafts is usually increased by using a radius at the ends of each main and crankpin bearing. The radius itself reduces the stress in these critical areas, but since the radius in most cases is rolled, this also leaves some compressive residual stress in the surface, which prevents cracks from forming. Hardening Most production crankshafts use induction hardened bearing surfaces, since that method gives good results with low costs. It also allows the crankshaft to be reground without re-hardening. But high performance crankshafts, billet crankshafts in particular, tend to use nitridization instead. Nitridization is slower and thereby more costly, and in addition it puts certain demands on the alloying metals in the steel to be able to create stable nitrides. The advantage of nitridization is that it can be done at low temperatures, it produces a very hard surface, and the process leaves some compressive residual stress in the surface, which is good for fatigue properties. The low temperature during treatment is advantageous in that it doesn’t have any negative effects on the steel, such as annealing. With crankshafts that operate on roller bearings, the use of carburization tends to be favored due to the high Hertzian contact stresses in such an application. Like nitriding, carburization also leaves some compressive residual stresses in the surface.
- Counterweights Some expensive, high performance crankshafts also use heavy-metal counterweights to make the crankshaft more compact. The heavy-metal used is most often a tungsten alloy but depleted uranium has also been used. A cheaper option is to use lead, but compared with tungsten its density is much lower. Stress on crankshaft The shaft is subjected to various forces but generally needs to be analysed in two positions. Firstly, failure may occur at the position of maximum bending; this may be at the centre of the crank or at either end. In such a condition the failure is due to bending and the pressure in the cylinder is maximal. Second, the crank may fail due to twisting, so the conrod needs to be checked for shear at the position of maximal twisting. The pressure at this position is the maximal pressure, but only a fraction of maximal pressure.
- LITERATURE REVIEW Yingkui and Zhibo [1] established three dimensional model ofa dieselengine crankshaft by using Pro E software. Using ANSYS analysis tool, the finite element analysis for the crankshaft was conducted under extreme operation conditions and stress distribution of the crankshaft was presented. The crank stress change model and the crank stress biggest hazard point were found by using finite element analysis, and the improvement method for the crankshaft structure design was given. This shows that the high stress region mainly concentrates in the Knuckles of the crank arm & the main journal, and the crank arm and the connecting rod journal, which is the area most easily broken. Jian et al. [2] analyzed three dimensional model of 380 diesel engine crankshaft. They used ProE and ANSYS as FEA tools. First of all, the 380 diesel engine entity crankshaft model was created by Pro E software. Next, the model was imported to ANSYS software. Material properties, constraints boundary conditions and mechanical boundary conditions of the 380 diesel engine crankshaft were determined. Finally, the strain and the stress figures of the 380 diesel crankshaft were calculated combined with maximum stress point and dangerous area. This article checked the crankshaft’s static strength and fatigue evaluations. That provided theoretical foundation for the optimization and improvement of engine design. The maximum deformation occurs in the end of the second cylinder balance weight. Gu Yingkui et.al. [3] researched a three-dimensional model of a diesel engine crankshaft was established by using PRO/E software. Using ANSYS analysis tool, it shows that the high stress region mainly concentrates in the knuckles of the crank arm & the main journal and the crank arm & connecting rod journal ,which is the area most easily broken. Jian Meng et al. [4] analyzed crankshaft model and crank throw were created by Pro/ENGINEER software and then imported to ANSYS software. The crankshaft deformation was mainly bending deformation under the lower frequency. And the maximum deformation was located at the link between main bearing journal, crankpin and crank cheeks.
- Xiaorong Zhou et al. [5] described the stress concentration in static analysis of the crankshaft model. The stress concentration is mainly occurred in the fillet of spindle neck and the stress of the crankpin fillet is also relatively large. Based on the stress analysis, calculating the fatigue strength of the crankshaft will be able to achieve the design requirements. From the natural frequencies values, it is known that the chance of crankshaft resonant is unlike. This paper deals with the dynamic analysis of the whole crankshaft. Farzin H. Montazersadgh et al.
- CHAPTER-2 CAD-DESIGN TOOL Computer Aided Design & Drafting CREO
- INTRODUCTION: CREO .1. CAD Computer aided design (cad) is defined as any activity that involves the effective use of the computer to create, modify, analyze, or document an engineering design. CAD is most commonly associated with the use of an interactive computer graphics system, referred to as cad system. The term CAD/CAM system is also used if it supports manufacturing as well as design applications .2. Introduction to CREO CREO is a suite of programs that are used in the design, analysis, and manufacturing of a virtually unlimited range of product. CREO is a parametric, feature-based solid modeling system, “Feature based” means that you can create part and assembly by defining feature like pad, rib, slots, holes, rounds, and so on, instead of specifying low-level geometry like lines, arcs, and circle& features are specifying by setting values and attributes of element such as reference planes or surfaces direction of creation, pattern parameters, shape, dimensions and others. “Parametric” means that the physical shape of the part or assembly is driven by the values assigned to the attributes (primarily dimensions) of its features. Parametric may define or modify a feature’s dimensions or other attributes at any time.
- For example, if your design intent is such that a hole is centered on a block, you can relate the dimensional location of the hole to the block dimensions using a numerical formula; if the block dimensions change, the centered hole position will be recomputed automatically. “Solid Modeling” means that the computer model to create it able to contain all the information that a real solid object would have. The most useful thing about the solid modeling is that it is impossible to create a computer model that is ambiguous or physically non-realizable. There are six core CREO concepts. Those are: Solid Modeling Feature Based Parametric Parent / Child Relationships Associative Model Centric .3 Capabilities and Benefits: 1. Complete 3D modeling capabilities enable you to exceed quality arid time to arid time to market goals. 2. Maximum production efficiency through automated generation of associative C tooling design, assembly instructions, and machine code. 3. Ability to simulate and analysis virtual prototype to improve production performance and optimized product design. 4. Ability to share digital product data seamlessly among all appropriate team members
- 5. Compatibility with myriad CAD tools-including associative data exchange and industry standard data formats. .4 Features of CREO CREO is a one-stop for any manufacturing industry. It offers effective feature, incorporated for a wide variety of purpose. Some of the important features are as follows: Simple and powerful tool Parametric design Feature-based approach Parent child relationship Associative and model centric 4.1. Simple and Powerful Tool CREO tools are used friendly. Although the execution of any operation using the tool can create a highly complex model 4.2. Parametric Design CREO designs are parametric. The term “parametric” means that the design operations that are captured can be stored as they take place. They can be used effectively in the future for modifying and editing the design. These types of modeling help in faster and easier modifications of design 4.3. Feature-Based Approach Features are the basic building blocks required to create an object. CREO wildfire models are based on the series of feature. Each feature builds upon the previous feature, to create the
- model (only one single feature can be modified at a time). Each feature may appear simple, individually, but collectively forms a complex part and assemblies. The idea behind feature based modeling is that the designer construct on object, composed of individual feature that describe the manner in which the geometry supports the object, if its dimensions change. The first feature is called the base feature. 4.4. Parent Child Relationship The parent child relationship is a powerful way to capture your design intent in a model. This relationship naturally occurs among features, during the modeling process. When you create a new feature, the existing feature that are referenced, become parent to the feature. 4.5. Associative and Model Centric CREO drawings are model centric. This means that CREO models that are represented in assembly or drawings are associative. If changes are made in one module, these will automatically get updated in the referenced module. 5. CREO Basic Design Modes When a design from conception to completion in CREO, the design information goes through three basic design steps. 1. Creating the component parts of the design 2. Joining the parts in an assembly that records the relative position of the parts. 3. Creating mechanical drawing based on the information in the parts and the assembly.
- 6 Assembly in CREO: Bottom-Up Design (Modeling): The components (parts) are created first and then added to the assembly file. This technique is particularly useful when parts already exist from previous designs and are being re-used. Top-Down Design (Modeling): The assembly file is created first and then the components are created in the assembly file. The parts are build relative to other components. Useful in new designs In practice, the combination of Top-Down and Bottom-Up approaches is used. As you often use existing parts and create new parts in order to meet your design needs. Degrees of Freedom: An object in space has six degrees of freedom. • Translation – movement along X, Y, and Z axis (three degrees of freedom) • Rotation – rotate about X, Y, and Z axis (three degrees of freedom) Assembly Constraints: In order to completely define the position of one part relative to another, we must constrain all of the degrees of freedom COINCIDENT, OFFSET OFFSET Two surfaces are made parallel with a specified offset distance. .
- COINCIDENT Two selected surfaces become co-planar and face in the same direction. Can also be applied to revolved surfaces. This constrains 3 degrees of freedom (two rotations and one translation). When Align is used on revolved surfaces,they become coaxial (axes through the centers align). CREO Modules:- Sketcher (2D) Part (3D) Assembly Drawing and Drafting Sheet Metal Surface modeling
- 3D MODEL IS DEVELOPED USING CREO:- 3D MODEL DEVOLOPING:
- CHAPTER-3 CAE-ANALYSIS TOOL ANSYS(Analytical System)
- ANALYSIS ANSYS is an Engineering Simulation Software (computer aided Engineering). Its tools cover Thermal, Static, Dynamic, and Fatigue finite element analysis along with other tools all designed to help with the development of the product. The company was founded in 1970 by Dr. John A. Swanson as Swanson Analysis Systems, Inc. SASI. Its primary purpose was to develop and market finite element analysis software for structural physics that could simulate static (stationary), dynamic (moving) and heat transfer (thermal) problems. SASI developed its business in parallel with the growth in computer technology and engineering needs. The company grew by 10 percent to 20 percent each year, and in 1994 it was sold. The new owners took SASI’s leading software, called ANSYS®, as their flagship product and designated ANSYS, Inc. as the new company name. 3.1. BENEFITSOF ANSYS: The ANSYS advantage and benefits of using a modular simulation system in the design process are well documented. According to studies performed by the Aberdeen Group, best-in-class companies perform more simulations earlier. As a leader in virtual prototyping, ANSYS is unmatched in terms of functionality and power necessary to optimize components and systems. The ANSYS advantage is well-documented. ANSYS is a virtual prototyping and modular simulation system that is easy to use and extends to meet customer needs, making it a low-riskinvestment that canexpand as value is demonstrated within a company. It is scalable to all levels of the organization, degrees of analysis complexity, and stages of product development.
- 3.2.Finite Element Method General Description ofthe Finite Element Method: In the finite element method, the actual continuum or body of matter like solid, liquid or gas is represented as assemblage of sub divisions called finite elements. These elements are considered to be interconnected at specified joints, which are called nodes or nodal points. The nodes usually lie on the element boundaries where adjacent elements are considered to be connected. Since the actualvariation of the field variable (like displacement, stress, temperature, pressure and velocity) inside the continuum is not known, we assume that the variation of field variable inside a finite element can be approximated by a simple function. These approximating functions (also called interpolation models) are defined in terms of the values at the nodes. Structural Analysis: Structural analysis is probably the most common application of the finite element method. The term structural (or structure) implies not only civil engineering structures such as ship hulls, aircraft bodies, and machine housings, as well as mechanicalcomponents such as pistons, machine parts, and tools. Types of Structural Analysis: Different types of structural analysis are: Static analysis Modal analysis Harmonic analysis Transient dynamic analysis Spectrum analysis Bucking analysis Explicit dynamic analysis Static Analysis: A static analysis calculates the effects of steady loading conditions on a structure, while ignoring inertia and damping effects, such as those caused by time varying loads. A static analysis can, however, include steady inertia loads (such as gravity and rotational velocity), and time-varying
- loads that can be approximated as static equivalent loads (such as the static equivalent wind arid seismic loads commonly defined in many building codes). Static analysis is used to determine the displacements, stresses, strains, and forces in structural components caused by loads that do not induce significant inertia and damping effects. Steady loading and response are assumed to vary slowly with respect to time. The kinds of loading that can be applied in a static analysis include: Externally applied forces and pressures Steady-state inertial forces (such as gravity or rotational velocity) Imposed (non-zero) displacements Temperatures (for thermal stain) Fluences (for nuclear swelling) A static analysis can be either linear or non-linear. All types of non-linearities are allowed-large deformations, plasticity, creep, stress, stiffening, contact (gap) elements, hyper elastic elements, and so on. Over-view of steps in a static analysis: The procedure for a modal analysis consists of three main steps: 1. Build the model. 2. Apply loads and obtain the solution. 3. Review the results
- BASIC STEPS IN ANSYS (Finite Element Software): Pre-Processing (Defining the Problem): The major steps in pre-processing are given below Define key points/lines/ areas/volumes. Define element type and material/geometric properties Mesh lines/ areas/volumes as required. The amount of detail required will depend on the dimensionality of the analysis (i.e., 1D, 2D, axi-symmetric, 3D). Solution (Assigning Loads, Constraints, And Solving): Here the loads (point or pressure), constraints (translational and rotational) are specified and finally solve the resulting set of equations. Post Processing: In this stage, further processing and viewing of the results can be done such as: Lists of nodal displacements Element forces and moments Deflection plots Stress contour diagrams
- Advanced Post-Processing: ANSYS provides a comprehensive set of post-processing tools to display results on the models as contours or vector plots, provide summaries of the results (like min/max values and locations). Powerful and intuitive slicing techniques allow to get more detailed results over given parts of your geometries. All the results can also be exported as text data or to a spreadsheet for further calculations. Animations are provided for static cases as well as for nonlinear or transient histories. Any result or boundary condition can be used to create customized charts. Exploring design: A single simulation just provides a validation ofa design. ANSYS brings you to the next level with designxplorer a tool designed for fast and efficient design analysis. You will not need more than a few mouse clicks to get a depper understanding of your design, whether you want to examine multiple scenarios or create full response surfaces of your model and get sensitivities to design parameters, optimize your model or perform a Six Sigma analysis.
- Communicating results: ANSYS lets you explore your design in multiple ways. All the results you get must then be efficiently documented: ANSYS will provide you instantaneous report generation to gather all technical data and pictures of the model in a convenient format (html, MS Word, MS PowerPoint…).Capturing the knowledge:
- ANSYS For all engineers and students coming to finite element analysis or to ANSYS software for the first time, this powerful hands-on guide develops a detailed and confident understanding of using ANSYS's powerful engineering analysis tools. The best way to learn complex systems is by means of hands-on experience. With an innovative and clear tutorial based approach, this powerful book provides readers witha comprehensive introduction to all of the fundamental areas of engineering analysis they are likely to require either as part of their studies or in getting up to speed fast with the use of ANSYS software in working life. Opening with an introduction to the principles of the finite element method, the book then presents an overview of ANSYS technologies before moving on to cover key applications areas in detail. Key topics covered: Introduction to the finite element method Getting started with ANSYS software stress analysis dynamics of machines fluid dynamics problems thermo mechanics contact and
- surface mechanics exercises, tutorials, worked examples With its detailed step-by-step explanations, extensive worked examples and sample problems, this book will develop the reader's understanding of FEA and their ability to use ANSYS's software tools to solve their ownparticular analysis problems, not just the ones set in the book. At ANSYS, we bring clarity and insight to customers' most complex design challenges through fast, accurate and reliable simulation. Our technology enables organizations to predict with confidence that their products will thrive in the real world. They trust our software to help ensure product integrity and drive business success through innovation. Every product is a promise to live up to and surpass expectations. By simulating early and often with ANSYS software, our customers become faster, more cost-effective and more innovative, realizing their own product promises.
- CHAPTER-4 Material selection
- A material's property is an intensive, often quantitative, property of some material. Quantitative properties may be used as a metric by which the benefits of one material versus another can be assessed, thereby aiding in materials selection. A property may be a constant or may be a function of one or more independent variables, such as temperature. Materials properties often vary to some degree according to the direction in the material in which they are measured, a condition referred to as anisotropy. Materials properties that relate to different physical phenomena often behave linearly (or approximately so) in a given operating range. Modelling them as linear can significantly simplify the differential constitutive equations that the property describes. Some materials properties are used in relevant equations to predict the attributes of a system a priori. For example, if a material of a known specific heat gains or loses a known amount of heat, the temperature change of that material can be determined. Materials properties are most reliably measured by standardized test methods. Many such test methods have been documented by their respective user communities and published through ASTM International. Mechanicalproperties: Young’s modulus: Young's modulus, also known as the tensile modulus or elastic modulus, is a mechanical property of linear elastic solid materials. It measures the force (per unit area) that is needed to stretch (or compress) amaterial sample. Young's modulus is named after the 19th-century British scientist Thomas Young. However, the concept was developed in 1727 by Leonhard Euler, and the first experiments that used the concept of Young's modulus in its current form were performed by the Italian scientist Giordano Riccati in 1782, pre-dating Young's work by 25 years. The term modulus is the diminutive of the Latin term modus which meansmeasure. A solid body deforms when a load is applied to it. If the material is elastic, the body returns to its original shape after the load is removed. The material is linear if the ratio of load to deformation remains constant during the loading process. Not many materials are linear and elastic beyond a small amount of
- deformation. A constant Young's modulus applies only to linear elastic materials. A rigid material has an infinite Young's modulus because an infinite force is needed to deform such a material. A material whose Young'smodulusisveryhighcan be approximatedasrigid. A stiff material needs more force to deform compared to a soft material. Therefore, the Young's modulusisa measure of the stiffness of asolidmaterial.Donotconfuse: stiffness and strength: the strength of material is the amount of force it can withstand and still recoveritsoriginal shape; material stiffness and geometric stiffness: the geometric stiffness depends on shape, e.g. the stiffness of an I beam is much higher than that of a spring made of the same steel thus having the same rigidity; stiffness and hardness: the hardness of a material defines the relative resistance that its surface imposesagainstthe penetrationof aharderbody; Stiffness and toughness: toughness is the amount of energy that a material can absorb before fracturing. Young's modulus is the ratio of stress (which has units of pressure) to strain (which is dimensionless), and so Young's modulus has units of pressure. Its SI unit is therefore the Pascal (Pa or N/m2 or m−1·kg·s−2). The practical units used are mega Pascal’s (MPa or N/mm2) or (GPa or kN/mm2). In United States customary units, it is expressed as pounds (force) per square inch (psi). The abbreviation ksi refers to "kpsi", or thousands of pounds per square inch. The Young's modulus enables the calculation of the change in the dimension of a bar made of an isotropic elastic material under tensile or compressive loads. For instance, it predicts how much a material sample extends under tension or shortens under compression. The Young's modulus directly applies to cases uniaxial stress, that is tensile or compressive stress in one direction and no stress in the other directions. Young's modulus is also used in order to predict the deflection that will occur in a statically determinate beam when a load is applied at a point in between the beam's supports. Other elastic calculations usually require the use of one additional elastic property, such as the shear modulus, bulk modulus or Poisson's ratio. Any two of these parameters are sufficient to fully describe elasticityinanisotropicmaterial.
- Young's modulus, E, can be calculated by dividing the tensile stress by the extensional strain in the elastic(initial,linear)portionof the stress–straincurve: where E is the Young's modulus(modulusof elasticity) F isthe force exertedonanobjectundertension; A0 isthe original cross-sectional areathroughwhichthe force isapplied; ΔL isthe amount bywhichthe lengthof the objectchanges; L0 is the original lengthof the object. Poison’s ratio: Poisson's ratio, named after Siméon Poisson, is the negative ratio of transverse to axial strain. When a material is compressed in one direction, it usually tends to expand in the other two directions perpendicular to the direction of compression. This phenomenon is called the Poisson effect. Poisson's ratio (nu) is a measure of thiseffect. The Poisson ratio is the fraction (or percent) of expansion divided by the fraction(orpercent) of compression,forsmall valuesof these changes. Conversely, if the material is stretched rather than compressed, it usually tends to contract in the directions transverse to the direction of stretching. This is a common observation when a rubber band is stretched, when it becomes noticeably thinner. Again, the Poisson ratio will be the ratio of relative contraction to relative expansion, and will have the same value as above. In certain rare cases, a material will actually shrink in the transverse direction when compressed (or expand when stretched) whichwill yieldanegative value of the Poissonratio. The Poisson's ratio of a stable, isotropic, linear elastic material cannot be less than −1.0 nor greater than 0.5 due to the requirement that Young's modulus, the shear modulus and bulk modulus have positive values. Most materials have Poisson's ratio values ranging between 0.0 and 0.5. A perfectly incompressible material deformed elastically at small strains would have a Poisson's ratio of exactly 0.5.
- Most steels and rigid polymers when used within their design limits(before yield) exhibit values of about 0.3, increasing to 0.5 for post-yield deformation (Seismic Performance of Steel-Encased Concrete Piles by RJT Park) (which occurs largely at constant volume.) Rubber has a Poisson ratio of nearly 0.5. Cork's Poisson ratio is close to 0: showing very little lateral expansion when compressed. Some materials, mostly polymer foams, have a negative Poisson's ratio; if these auxetic materials are stretched in one direction, they become thicker in perpendicular direction. Some anisotropic materials have one or more Poissonratiosabove 0.5 insome directions. Assuming that the material is stretched or compressed along the axial direction (the x axis in the below diagram): where is the resultingPoisson'sratio, is transverse strain (negative for axial tension (stretching), positive for axial compression) is axial strain(positive foraxial tension,negative foraxial compression). Shear stress A shear stress, denoted (Greek: tau), is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross sectiononwhichitacts. The formula to calculate average shear stress is force per unit area. where: = the shearstress; = the force applied; = the cross-sectional areaof material withareaparallel tothe appliedforce vector
- Yield strength: A yield strength or yield point of a material is defined in engineering and materials science as the stress at which a material begins to deform plastically. Prior to the yield point the material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible. In the three-dimensional space of the principal stresses, an infinite number of yield points form together a yield surface. Knowledge of the yield point is vital when designing a component since it generally represents an upper limit to the load that can be applied. It is also important for the control of many materials production techniques such as forging, rolling, or pressing. In structural engineering, this is a soft failure mode which does not normally cause catastrophic failure or ultimate failure unless it accelerates buckling. It is often difficult to precisely define yielding due to the wide variety of stress–strain curves exhibited by real materials.Inaddition,thereare several possible waystodefineyielding: True elastic limit The lowest stress at which dislocations move. This definition is rarely used, since dislocations move at verylowstresses,anddetectingsuchmovementisverydifficult. Proportionality limit Up to this amount of stress, stress is proportional to strain (Hooke's law), so the stress-strain graph is a straightline,andthe gradientwill be equal tothe elasticmodulus of the material. Elastic limit (yieldstrength) Beyond the elastic limit, permanent deformation will occur. The elastic limit is therefore the lowest stress at which permanent deformation can be measured. This requires a manual load-unload procedure, and the accuracy is critically dependent on the equipment used and operator skill. For elastomers, such as rubber, the elastic limit is much larger than the proportionality limit. Also, precise strainmeasurementshave shownthatplasticstrainbeginsatlow stresses.
- Yieldpoint The pointin the stress-straincurve atwhichthe curve levelsoff andplastic deformationbeginstooccur. Offset yieldpoint (proof stress) When a yield point is not easily defined based on the shape of the stress-strain curve an offset yield point is arbitrarily defined. The value for this is commonly set at 0.1 or 0.2% plastic strain.[ The offset value is given as a subscript, e.g., Rp0.2=310 MPa. High strength steel and aluminum alloys do not exhibit a yieldpoint,sothisoffsetyieldpointisusedonthese materials Upper and lower yieldpoints Some metals, such as mild steel, reach an upper yield point before dropping rapidly to a lower yield point. The material response is linear up until the upper yield point, but the lower yield point is used in structural engineering as a conservative value. If a metal is only stressed to the upper yield point, and beyond, Lüdersbands candevelop Castiron Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%. The alloy constituents affect its colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight through. Grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks. Carbon (C) and silicon (Si) are the main alloying elements, with the amount ranging from 2.1–4 wt% and 1–3 wt%, respectively. Iron alloys with less carbon content are known as steel. While this technically makes these base alloys ternary Fe–C–Si alloys, the principle of cast iron solidification is understood from the binary iron–carbonphase diagram. Since the compositions of most cast irons are around the eutectic point of the iron–carbon system, the melting temperatures closely correlate, usually ranging from 1,150 to 1,200 °C (2,100 to 2,190 °F), which is about 300 °C (572 °F) lower than the melting point of pure iron. Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity, castability, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are used in
- pipes, machines and automotive industry parts, such as cylinder heads (declining usage), cylinder blocks and gearbox cases (declining usage). It is resistant to destruction and weakening by oxidation (rust). The earliest cast iron artefacts date to the 5th century BC, and were discovered by archaeologists in what is now Jiangsu in China. Cast iron was used in ancient China for warfare, agriculture, and architecture. During the 15th century, cast iron became utilized for artillery in Burgundy, France, and in England during the Reformation. The first cast iron bridge was built during the 1770s byAbraham Darby III, and is known as The Iron Bridge. Cast iron is also used in the construction of buildings. SAE 1045 1045 is a medium tensile low hardenability carbon steel generally supplied in the black hot rolled or occasionally in the normalised condition, with a typical tensile strength range 570 - 700 Mpa and Brinell hardness range 170 - 210 in either condition.Characterised by fairly good strength and impact properties, plus good machinability and reasonable weldability in the hot rolled or normalised condition. 1045 has a low through hardening capability with sections up to around 60mm only generally recommended as suitable for through hardening and tempering. It can however be successfully flame or induction hardened in the as rolled or normalised condition resulting in surface hardnesses of up to Rc 54 - Rc 60 depending upon quenching medium employed, type of set up, section size etc. Core strengths will remain as supplied. It does not however respond satisfactorily to nitriding due to a lack of suitable alloying elements. 1045 is used extensively by all industry sectors for applications requiring more strength and wear resistance than the low carbon mild steels can provide and the higher strength of the low alloy high tensile steels is not necessary, plus those applications requiring flame or induction hardening. Typical applications are: Axles Various, Bolts, Connecting Rods, Hydraulic Clamps and Rams, Pins Various, Rolls Various, Studs, Shafts, Spindles etc.
- SAE 1137 Carbon steels contain carbon as the key alloying element. They are designated by AISI four-digit numbers, and contain 0.4% of silicon and 1.2% of manganese. Molybdenum, chromium, nickel, copper, and aluminium are present in small quantities. Impurities such as sulfur and phosphorous may also be found in these steels. The following datasheet gives an overview of AISI 1137 carbon steel. Element Content (%) Iron, Fe ~98 Manganese, Mn 1.35-1.65 Carbon, C 0.32-0.39 Sulphur, S 0.08-0.13 Phosphorous, P 0.04 (max) En9 EN9, also known as 070m55, available in diameters, flats, squares and plates with a carbon content 0.50/0.60 this is a medium carbon steel which can develop a tensile strength of 700N/mm 45tsi. In the normalised condition EN9 can be used for gears, sprockets and cams.
- ANSYS PROCESS:- IMPORTING THE COMPONEENT FROM CAD (CREO) TOOL TO CAE TOOL (ANSYS): STRUCTURAL ANALYSIS:- 1. Click on Ansys workbench Static structural
- 3.engineering dataright click enter values FOR CAST -IRON Ex: - 120*10^9 Pa Poison ratio: 0.3 Density: 7200 Kg/m^3 Yield strength: 195 Mpa SAE 1045 Ex: 200*10^9 Pa Poison ratio: 0.29 Density: 7870 kg/m^3 Yield strength: 400 Mpa SAE 1137 Ex: - 200*10^9 pa Poison ratio: 0.29 Density: 7800 kg/m^3 Yield strength: 500*10^6 pa EN9 Ex: - 210*10^9 pa Poison ratio: 0.29 Density: 7850 kg/m^3 Yield strength: 355*10^6 mpa
- 4. Geometry right click import geometry import iges format model Model imported from pro-e tool in IGES format. Imported Model View In Ansys. Meshing: - Volume Mesh - Tetmesh. Tet Volume Mesh
- Select geometry assign material properties Click on static structural supports fixed supports loadspressure 8*10^6 pa apply Loads moment 180 n-m Inertia rotational velocity 500 rad/s . Solutiondeformationsolve Repeat same process for von-misess stress, factor of safety then solve Results:
- Material : Cast iron Deformation: Von mises stress Factor of safety
- Material : SAE 1045 Deformation: Von mises stress
- FOS Material : sae 1137 DEFORMATION
- STRESS: FOS
- Material : EN9 DEFORMATION: STRESS:
- FOS:
- Tables Case1 Cast-iron En9 Sae1045 Sae1137 Deformation (mm) 0.031471 0.01895 0.019 0.019 Safety factor 0.5066 0.92 1.03 1.2987 Stress (Mpa) 384.89 385.02 385.03 385.01 Graphs Deformation Stress 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 cast-iron en9 sae-1045 sae1137
- Safety factor 384.8 384.85 384.9 384.95 385 385.05 cast-iron en9 sae-1045 sae1137 stress stress 0 0.2 0.4 0.6 0.8 1 1.2 1.4 cast-iron en9 sae1045 sae1137 safety factor safety factor
- CASE2: Select geometry assign material properties Click on static structural supports fixed supports loadspressure 4.5*10^6 pa apply Loads moment 130 n-m Inertia rotational velocity 500 rad/s . Solutiondeformationsolve Repeat same process for von-misess stress, factor of safety then solve
- Results: Material : Cast iron Deformation: Von mises stress
- Factor of safety Material : sae 1045 Deformation:
- Von mises stress FOS
- Material : sae 1137 DEFORMATION STRESS:
- FOS Material : EN9 DEFORMATION:
- STRESS: FOS:
- Case2 Cast-iron En9 Sae1045 Sae1137 Deformation (mm) 0.022 0.013 0.013 0.013 Safety factor 0.700 1.27 1.43 1.79 Stress (Mpa) 278.39 278.52 278.53 278.51 Graphs Deformation 0 0.005 0.01 0.015 0.02 0.025 cast-iron en9 sae1045 sae1137 deformation deformation
- Stress Safety factor 278.3 278.35 278.4 278.45 278.5 278.55 cast-iron en9 sae1045 sae1137 stress stress 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 cast-iron en9 sae1045 sae1137 safety factor safety factor
- CONCLUSION The single cylinder crankshaft model was created by creo-2 software. Then, the model imported into ANSYS software. Then we analysing our model with 2 different cases in each case we applying four different material properties, we found deformations, von-mises stress, safety factor, by considering all results in cases SAE1137 material having good strength and low stress values at high rotational velocity and high pressure and torque respectively. By this changes we can say, this crankshaft can run at high velocity high rpm condition without braking and producing good strength to weight ratio also. . The Value of Von-Misses Stresses that comes out from the analysis is far less than material yield stress so our design is safe and we should go for optimization to reduce the material and cost. Accurate stresses and deformation are critical input to fatigue analysis and optimization of the crankshaft. REFERENCES
- 1.Yu Ding and Xiaobo Li.,2011, “ Crankshaft Strength Analysis of a Diesel Engine Using Finite Element Method,” Asia-Pacific Power and Energy Engineering Conference 2. Jian Meng., Yongqi Liu., Ruixiang Liu.,2011,“Finite Element Analysis of 4-Cylinder Diesel Crankshaft, ” I.J. Image, Graphics and Signal Processing, 5, 22-29 3. MENG Jian., LIU Yong-qi., LIU Rui-xiang., and ZHENG Bin.,2011,“Intension Analysis of3-D Finite Element Analysis on 380 diesel crankshaft,” International Conference on Computational and Information Sciences 4.Mr.S.J Patil “ Modal analysis of compressor crankshaft”, International Journal of Scientific Reasearch, vol-2, Issue:7, ISSN: 2277-8179, Pages: 155-158, July-2013. [5] Momin Muhammad Zia Muhammad Idris “ Optimization of crankshaft using strength analysis”, International Journal of Engineering Reasearch and applications, Vol-3, Issue-3, ISSN:2248-9622, Pages: 252-258, May-Jun-2013. [6] Rincle Garg, Sunil Baghla, “Finite element analysis and optimization of crankshaft”, International Journal of Engineering and Management Reaserch, vol-2,Issue-6,ISSN: 2250-0758, Pages:26-31, December 2012. [7] BDNS Murthy “ Modeling analysis and optimization of crankshaft”, vol-2, Issue-9, ISSN: 2278-0181, Pages: 749-753, September-2013.

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