1. Mekanika Metalurgi 2010 PENGUJIAN TARIK Oleh : Farid Widi Arfika 2406 100 013 Teknik Fisika Fakultas Teknologi Industri Institut Teknologi Sepuluh Nopember Surabaya

2. Tujuan Uji Tarik Pengujian tarik bertujuan untuk mengetahui sifat-sifat mekanik dan perubahan perubahannya

3. Definisi Stress – Strain Engineering Stress Engineering Strain Direct Stress - Tension Direct Stress - Compression

4. Poisson’s Ratio RANGES 0.25 – 0.27 for Cast Iron 0.27 – 0.30 for Steel 0.30 – 0.33 for Aluminum and Titanium

5. Poisson’s Ratio

6. Shear Stress and Strain Shear Stress Shear Strain shear stress, t = Shear Load / Area shear strain, g = angle of deformation (radians) shear modulus, G = t /g (elastic region)

7. Modulus of Rigidity in Shear Measure of resistance to shear deformation.

10. Engineering Stress-Strain Curve Elongation Sy 0.2% offset yield stress Engineering Stress, S=P/Ao (Ultimate) E Su E Proportional Limit Engineering Strain, e = DL/Lo)

11. 11 TegangandanRegangan dari Bahanbajalunak

12. 12 Mulaidari O ke A = garislurusberarti linier atauproporsionaldisebut modulus elastisitas Titik B titikluluh Antara B dan C terjadiperpanjangantanpaadapertambahangayatarikdisebutplastissempurna Utk material logam, umumnya deformasielastisterjadi < 0,005 regangan Regangan > 0,005 terjadideformasiplastis (deformasipermanen)

13. Engineering Stress-Strain Curve Elongation Sy 0.2% offset yield stress Engineering Stress, S=P/Ao (Ultimate) E Su E Proportional Limit Engineering Strain, e = DL/Lo)

14. Example: find yield strength, ultimate strength and modulus of elasticity:

15. Example: find yield strength and ultimate for material that does not exhibit knee behavior

19. Elastic and Plastic Strain P (e,S) Stress Total Strain The 0.2% offset yield stress is the stress that gives a plastic (permanent) strain of 0.002. Strain Plastic Elastic ee ep

20. Ductile Vs Brittle Materials Ductile if EL%>8% (approximately) Brittle if EL% < 5% (approximately) Engineering Stress Engineering Strain

21. Keuletan(Ductility)- EL% & AR% Elongation Area Reduction Lo Ao Lf Af

22. Brittle Materials The stress-deflection curve for MgO obtained from a bend test.

23. Ketangguan(Toughness), Ut Su Sy Engineering Stress, S=P/Ao Engineering Strain, e = DL/Lo)

25. Kelentingan (Resilience), Ur Su Sy Engineering Stress, S=P/Ao E ey Engineering Strain, e = DL/Lo)

26. Tegangan sejati , regangan sejati (true stress, true strain)

27. Perbandinganantarakurvategangan-reganganrekayasadansesungguhnyadaribajakarbonrendah (mild steel)

28. Mode Perpatahan Material

29. PerpatahanUlet Tahapanterjadinyaperpatahanuletpadasampelujitarik: (a) Penyempitanawal; (b) Pembentukanrongga-ronggakecil (cavity); (c) Penyatuanrongga-ronggamembentuksuaturetakan; (d) Perambatanretak; (e) Perpatahangeserakhirpadasudut 45°.

30. foto SEM dariperpatahanulet Tampilanpermukaanpatahandarisuatusampellogam yang ditandaidenganlubang-lubangdimpelsebagaisuatuhasilprosespenyatuanrongga-ronggakecil(cavity) selamapembebananberlangsung

32. Retak/perpatahanmerambatsepanjangbidang-bidangkristalinmembelah atom-atom material (transgranular).

33. Padamaterial lunakdenganbutirkasar (coarse-grain) makadapatdilihatpola-pola yang dinamakan chevrons or fan-like patternyang berkembangkeluardaridaerahawalkegagalan.

34. Material kerasdenganbutirhalus (fine-grain) tidakmemilikipola-polayang mudahdibedakan.

36. Contoh Material Uji Tarik

37. Polimer Skema percobaan perpanjangan untuk polimer semicrystalline seperti PE pada suhu kamar. (from Rodrigues) (Dari Rodrigues)

38. Polimer

39. Baja

40. Aluminium

41. Tension Test Measures P Extensometer Measures DL Typical Universal Testing Machine

42. Modern Materials Testing System Hydraulic Wedge Grips Specimen Extensometer

44. ASTM Tension Test Specimen Ao=0.20 in2 2” Gauge Length Lo

45. Typical Mechanical Properties Metals in annealed (soft) condition

46. TERIMAKASIH