Title Page
Contents
Ⅰ. Introduction 14
Ⅱ. GMAF working drawing development. 24
2.1. Analysis of GMAF 24
2.2. Boundary conditions 25
2.3. Von- Mises stresses for GMAF. 26
2.3.1. The upper fixture 28
2.3.2. The lower fixture 29
2.3.3. Two loading guide columns 30
2.3.4. Grips 32
Ⅲ. Specimen development for combined loading 33
3.1. Butterfly shaped specimen 33
3.2. The effect notch radius and notch angle 35
3.2.1. Effect on shear stress at 90° loading angle 36
3.2.2. Effect on tension stress at 0° loading angle 37
3.2.3. Effect on combined stresses at 45° loading angle 37
3.3. Dog bone specimen (CFRP/ Al bonded assembly) 38
3.3.1. Stress in all directions for position 90° dog bone specimen 39
3.3.2. Stress in all directions for position 0° dog bone specimen 40
3.4. Dog bone specimen (Al/ CFRP/ Al bonded assembly) 40
Ⅳ. Experimental 46
4.1. Material 46
4.2. Al/CFRP/Al specimen preparations 47
4.3. Equipment 49
4.4. Combined stress testing 50
4.5. Standard uniaxial tension test 51
4.6. Shear lap test 52
Ⅴ. Result and discussion 53
5.1. Force - displacement behavior 53
5.2. Combined stress diagram (shear versus tensile) 54
5.3. Confirmation of shear and tensile stresses using shear-lap and dog-bone tensile test 58
5.4. Failure criteria for adhesive bonded joint. 60
Ⅵ. Conclusions 64
Ⅶ. References 65
Abstract 71
Table 1. Aluminum alloy Al6061 properties. 46
Table 2. Adhesive material properties (Epoxy). 46
Table 3. Carbon fiber-reinforced polymer composites laminate [0/9] (CFRPs). 46
Table 4. Average shear and tension stress for all positions less scatter. 57
Table 5. Average shear and tension stress for all positions less scatter. 59
Table 6. Average shear stress using GMAF and double lap shear test. 59
Figure 1. Specimens for biaxial loadings: (a) tubular specimen subjected to combined tension and torsion [3], and (b) typical... 18
Figure 2. (a) Representation of different adhesive failure modes and (b) locations of high-stress concentration zones in adhesively-... 18
Figure 3. Assembled V-notched rail shear test apparatus. 19
Figure 4. The original Arcan sample with a significant section of the specimen AB. 19
Figure 5. Isoipescu test. 19
Figure 6. Modified Arcan test. 20
Figure 7. Modified Arcan fixture with loading guides. 23
Figure 8. loading Guide Modified Arcan Fixture (GMAF) system. 23
Figure 9. Dog bone specimen (tension specimen). 24
Figure 10. Boundary conditions and contact pairs adopted in GMAF. 25
Figure 11. Equivalent (von - Mises) stress for GMAF in pure shear loading angle (90°). 26
Figure 12. Equivalent (von - Mises) stress for GMAF in pure tension loading angle (0°). 26
Figure 13. Equivalent (von-Mises) stress for GMAF in combined load angle of (45°). 27
Figure 14. GMAF assembly. 28
Figure 15. Upper part of the GMAF. 29
Figure 16. Lower part of the GMAF. 30
Figure 17. Column (two loading guides connect between GMAF parts). 31
Figure 18. Grip to put the specimen in the center of the fixture. 32
Figure 19. Butterfly specimen. 33
Figure 20. Path shear stress distribution at the center of butterfly specimen at (90°) loading angle. 34
Figure 21. Tensile path stress distribution at the center of butterfly specimen at (0°) loading angle. 34
Figure 22. Different shape specimen. 35
Figure 23. Normalized shear path stress for different notch radius and notch angle at 90° loading angle. 36
Figure 24. Normalized tension path stress for different notch radius and notch angle at 0° loading angle. 37
Figure 25. Normalized (a) shear, and (b) tensile path stress for all specimens in combined at 45° loading angle. 38
Figure 26. Adhesive joint composite/metal. 39
Figure 27. Stress in all directions for the shear at (90°) loading angle dog bone specimen. 39
Figure 28. Stress in all directions for tension at (0°) loading angle dog bone specimen. 40
Figure 29. Adhesive joint metal/composite/metal. 41
Figure 30. Normalized path stress in all direction shear at (90°) loading angle adhesive-bonded joint. 42
Figure 31. Normalized path stress in all direction tension at(0°) loading angle adhesive -bonded joint. 42
Figure 32. Normalized path stress in all directions at (15°) loading angle adhesive- bonded joint. 43
Figure 33. Normalized path stress in all directions at (30°) loading angle adhesive-bonded joint. 44
Figure 34. Normalized path stress in all at (45°) loading angle adhesive-bonded joint. 44
Figure 35. Normalized path stress in all directions at (60°) loading angle adhesive -bonded joint. 45
Figure 36. Normalized path stress in all directions at (75°) loading angle adhesive-bonded joint. 45
Figure 37. Bog bond specimen Al. 48
Figure 38. Specially jig to made adessive joint. 48
Figure 39. Final Arcan specimen. 49
Figure 40. GMAF adjusted with UTM. 50
Figure 41. Different loading position of Arcan specimen with GMAF. 51
Figure 42. Standard uniaxial tension test. 52
Figure 43. (a) Sheal lap specimen and (b) shear lap test. 52
Figure 44. Force and displacement for all positions. 54
Figure 45. Shear strength versus tensile strength at all loading angles (0° -90°). 54
Figure 46. Fracture surfaces for adhesive joint at A. 56
Figure 47. Fracture surfaces for adhesive joint at B. 56
Figure 48. Shear strength versus tensile strength at all loading angles (0° -90°)less scatter. 57
Figure 49. Shear strength versus tensile strength at all loading angles (0° -90°), using GMAF, standard tensile test, double... 58
Figure 50. Adhesive pass stress distribution (a) standard tensile test (b) shear lap joint. 60
Figure 51. Drucker - Prager Model and Mohr - Coulomb model. 61
Figure 52. Failure envelope accurding to Drucker - Prager Model. 63