Pengujian tarik memet ppt

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Pengujian tarik memet ppt

  1. 1. Mekanika Metalurgi 2010<br />PENGUJIAN TARIK<br />Oleh :<br />Farid Widi Arfika<br />2406 100 013<br />Teknik Fisika<br />Fakultas Teknologi Industri<br />Institut Teknologi Sepuluh Nopember Surabaya<br />
  2. 2. Tujuan Uji Tarik<br /> Pengujian tarik bertujuan untuk mengetahui sifat-sifat mekanik dan perubahan perubahannya<br />
  3. 3. Definisi Stress – Strain <br />Engineering Stress<br />Engineering Strain<br />Direct Stress - Tension<br />Direct Stress - Compression<br />
  4. 4. Poisson’s Ratio<br />RANGES<br />0.25 – 0.27 for Cast Iron<br />0.27 – 0.30 for Steel<br />0.30 – 0.33 for Aluminum and Titanium<br />
  5. 5. Poisson’s Ratio<br />
  6. 6. Shear Stress and Strain<br />Shear Stress<br />Shear Strain<br />shear stress, t = Shear Load / Area<br />shear strain, g = angle of deformation (radians)<br />shear modulus, G = t /g (elastic region)<br />
  7. 7. Modulus of Rigidity in Shear<br />Measure of resistance to shear deformation.<br />
  8. 8.
  9. 9.
  10. 10. Engineering Stress-Strain Curve<br />Elongation<br />Sy<br />0.2% offset <br />yield stress<br />Engineering Stress, S=P/Ao <br />(Ultimate)<br />E<br />Su<br />E<br />Proportional Limit<br />Engineering Strain, e = DL/Lo)<br />
  11. 11. 11<br />TegangandanRegangan dari Bahanbajalunak<br />
  12. 12. 12<br />Mulaidari O ke A = garislurusberarti linier atauproporsionaldisebut modulus elastisitas<br />Titik B titikluluh<br />Antara B dan C terjadiperpanjangantanpaadapertambahangayatarikdisebutplastissempurna<br />Utk material logam, umumnya deformasielastisterjadi < 0,005 regangan<br />Regangan > 0,005 terjadideformasiplastis (deformasipermanen)<br />
  13. 13. Engineering Stress-Strain Curve<br />Elongation<br />Sy<br />0.2% offset <br />yield stress<br />Engineering Stress, S=P/Ao <br />(Ultimate)<br />E<br />Su<br />E<br />Proportional Limit<br />Engineering Strain, e = DL/Lo)<br />
  14. 14. Example: find yield strength, ultimate strength and modulus of elasticity:<br />
  15. 15. Example: find yield strength and ultimate for material that does not exhibit knee behavior<br />
  16. 16.
  17. 17.
  18. 18.
  19. 19. Elastic and Plastic Strain<br />P<br />(e,S)<br />Stress<br />Total Strain<br />The 0.2% offset yield stress<br />is the stress that gives a plastic<br />(permanent) strain of 0.002.<br />Strain<br />Plastic<br />Elastic<br />ee<br />ep<br />
  20. 20. Ductile Vs Brittle Materials<br />Ductile if EL%>8% (approximately)<br />Brittle if EL% < 5% (approximately) <br />Engineering Stress<br />Engineering Strain<br />
  21. 21. Keuletan(Ductility)- EL% & AR%<br />Elongation<br />Area Reduction<br />Lo<br />Ao<br />Lf<br />Af<br />
  22. 22. Brittle Materials<br />The stress-deflection curve for MgO obtained from a bend test.<br />
  23. 23. Ketangguan(Toughness), Ut<br />Su<br />Sy<br />Engineering Stress, S=P/Ao <br />Engineering Strain, e = DL/Lo)<br />
  24. 24.
  25. 25. Kelentingan (Resilience), Ur<br />Su<br />Sy<br />Engineering Stress, S=P/Ao <br />E<br />ey<br />Engineering Strain, e = DL/Lo)<br />
  26. 26. Tegangan sejati , regangan sejati (true stress, true strain) <br />
  27. 27. Perbandinganantarakurvategangan-reganganrekayasadansesungguhnyadaribajakarbonrendah (mild steel) <br />
  28. 28. Mode Perpatahan Material<br />
  29. 29. PerpatahanUlet<br />Tahapanterjadinyaperpatahanuletpadasampelujitarik: <br />(a) Penyempitanawal; <br />(b) Pembentukanrongga-ronggakecil (cavity); <br />(c) Penyatuanrongga-ronggamembentuksuaturetakan; <br />(d) Perambatanretak; <br />(e) Perpatahangeserakhirpadasudut 45°. <br />
  30. 30. foto SEM dariperpatahanulet<br />Tampilanpermukaanpatahandarisuatusampellogam yang ditandaidenganlubang-lubangdimpelsebagaisuatuhasilprosespenyatuanrongga-ronggakecil(cavity) selamapembebananberlangsung<br />
  31. 31. PerpatahanGetas<br />Perpatahangetasmemilikiciri-cirisebagaiberikut: <br /><ul><li>Tidakadaatausedikitsekalideformasiplastis yang terjadipadamaterial.
  32. 32. Retak/perpatahanmerambatsepanjangbidang-bidangkristalinmembelah atom-atom material (transgranular).
  33. 33. Padamaterial lunakdenganbutirkasar (coarse-grain) makadapatdilihatpola-pola yang dinamakan chevrons or fan-like patternyang berkembangkeluardaridaerahawalkegagalan.
  34. 34. Material kerasdenganbutirhalus (fine-grain) tidakmemilikipola-polayang mudahdibedakan.
  35. 35. Material amorphous (sepertigelas) memilikipermukaanpatahanyang bercahayadanmulus. </li></li></ul><li>foto SEM perpatahangetas<br />Perhatikanbentukperambatanretak yang menjalar<br />(a) memotongbutir (transgranular fracture) dan<br />(b) melaluibatasbutir material (intergranular fracture)<br />
  36. 36. Contoh Material Uji Tarik<br />
  37. 37. Polimer<br />Skema percobaan perpanjangan untuk polimer semicrystalline seperti PE pada suhu kamar. (from Rodrigues) (Dari Rodrigues)<br />
  38. 38. Polimer<br />
  39. 39. Baja<br />
  40. 40. Aluminium<br />
  41. 41. Tension Test<br />Measures P<br />Extensometer<br />Measures DL<br />Typical Universal <br />Testing Machine<br />
  42. 42. Modern Materials Testing System<br />Hydraulic<br />Wedge <br />Grips<br />Specimen<br />Extensometer<br />
  43. 43.
  44. 44. ASTM Tension Test Specimen<br />Ao=0.20 in2<br />2” Gauge Length<br />Lo<br />
  45. 45. Typical Mechanical Properties<br />Metals in annealed (soft) condition<br />
  46. 46. TERIMAKASIH<br />

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