Stress-Optical Microscopy Studies of the Microscopic Deformation and Failure Modes of Kevlar 49/Epoxy Composites

1983 ◽  
Vol 5 (3) ◽  
pp. 95 ◽  
Author(s):  
WW Feng ◽  
KL Reifsnider ◽  
GP Sendeckyj ◽  
TT Chiao ◽  
GL Rodericks ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Failure Modes ◽  
Epoxy Composites ◽  
Deformation And Failure ◽  
Microscopic Deformation

scholarly journals Characterization of Hybrid Oil Palm Empty Fruit Bunch/Woven Kenaf Fabric-Reinforced Epoxy Composites

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2052
Author(s):  
Farah Hanan ◽  
Mohammad Jawaid ◽  
Md Tahir Paridah ◽  
Jesuarockiam Naveen
Keyword(s):  
Impact Strength ◽  
Oil Palm ◽  
Failure Modes ◽  
Fiber Content ◽  
Epoxy Composites ◽  
Void Content ◽  
Empty Fruit Bunch ◽  
Kenaf Fiber ◽  
The Impact ◽  
Woven Kenaf

In this research, the physical, mechanical and morphological properties of oil palm empty fruit bunch (EFB) mat/woven kenaf fabric-reinforced epoxy composites have been investigated. The oil palm EFB/woven kenaf fabrics were varied, with weight ratios of 50/0 (T1), 35/15 (T2), 25/25 (T3), 15/35 (T4) and 0/50 (T5). The composites were fabricated using a simple hand lay-up technique followed by hot pressing. The result obtained shows that an increase in kenaf fiber content exhibited higher tensile and flexural properties. On the other hand, the opposite trend was observed in the impact strength of hybrid composites, where an increase in kenaf fiber content reduced the impact strength. This can be corroborated with the physical properties analysis, where a higher void content, water absorption and thickness swelling were observed for pure oil palm EFB (T1) composites compared to other samples. The scanning electron microscopy analysis results clearly show the different failure modes of the tensile fractured samples. Statistical analysis was performed using one-way ANOVA and shows significant differences between the obtained results.

scholarly journals Quasistatic deformation and failure modes of composite square honeycombs

2008 ◽  
Vol 3 (7) ◽  
pp. 1315-1340 ◽  
Author(s):  
Benjamin Russell ◽  
Vikram Deshpande ◽  
Haydn Wadley
Keyword(s):  
Failure Modes ◽  
Deformation And Failure

Deformation and Failure Characteristics of Embankment upon the Slope in Permafrost Area under Different Foundation Slope

2013 ◽  
Vol 353-356 ◽  
pp. 905-910
Author(s):  
Qian Su ◽  
Jun Jie Huang ◽  
Bao Liu ◽  
Yu Jie Li
Keyword(s):  
Failure Modes ◽  
Centrifuge Modeling ◽  
Experimental Conditions ◽  
Soil Layers ◽  
Deformation And Failure ◽  
Geotechnical Centrifuge ◽  
Gravity Load ◽  
Unstable Failure ◽  
Thawing Depth ◽  
The Stability

To investigate the effect of foundation slope on stability of embankment upon the slope in permafrost area, 3 groups of model tests with different foundation slope are designed using the mechanical similarity based on geotechnical centrifuge modeling, when the freezing-thawing depth of the embankment reaches the greatest. The results show that: (1) The foundation slope has effect on the stability of the embankment. The deformation mainly concentrates on the soil layers above the freezing-thawing interface, and the deformation mutation point takes place at the freezing-thawing interface. (2) According to fracture characteristics and failure severity of the embankment, failure modes can be divided into the cracking failure in shallow layer and in deep layer. (3) The cause of unstable failure is the deficiency of shear resistance strength of the weak belt, the soil layers above the freezing-thawing interface slips along the freezing-thawing interface under gravity load. (4) Under the experimental conditions, the critical value of the foundation slope influencing on the stability of the embankment is about 1:6 when the height of the slope embankment is 5.0 m.

scholarly journals Mechanical Characteristics and Failure Modes of Low-Strength Rock Samples with Dissimilar Fissure Dip Angles

2021 ◽  
Author(s):  
Y L Wang ◽  
D S Liu ◽  
K Li ◽  
X M Hu ◽  
D Chen
Keyword(s):  
Rock Mass ◽  
Mechanical Characteristics ◽  
Failure Modes ◽  
High Strength ◽  
Rock Masses ◽  
Deformation And Failure ◽  
Deformation Features ◽  
Low Strength ◽  
Dip Angle ◽  
Strength Rock

The mechanical characteristics and failure modes of low-strength rock sample with various fissure dip angles were investigated by conventional uniaxial compression test and three-dimensional (3D) crack reconstruction. The results indicated that compared with high-strength rock masses, cracks had different influences on the low-strength rock mass mechanical deformation features. Thereinto, the dip angle of fissures can cause post-peak failure stage of stress-strain curve change from swift decline to multi-step down, showing obvious ductility deformation and failure characteristics. Peak strength and elastic modulus owned an anti-S-shaped growth tendency with the growth of fissure dip angle, which was positively correlated and greatest subtle to the fissure dip angle α < 21° and α > 66.5°. The axial peak strain reduced first and enlarged rapidly with growing fissure dip angle, suggesting a V-shaped change trend. Increasing the fissure dip angle will change the sample failure mode, experienced complete tensile failure to tensile-shear composite failure, and ultimately to typical shear failure. Also, the crack start angle decreased with enlarging fissure dip angle, larger than that the high-strength rock mass fissure dip angle. The above research findings can complement and improve the study of fissured rock masses.

scholarly journals Deformation and Failure Analyses of the Surrounding Rock Mass with an Interlayer Shear Zone in the Baihetan Underground Powerhouse

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Fei Yuan ◽  
An-chi Shi ◽  
Jia-wen Zhou ◽  
Wang-bing Hong ◽  
Meng Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Shear Deformation ◽  
Shear Zone ◽  
Failure Modes ◽  
Shear Zones ◽  
Surrounding Rock ◽  
Left Bank ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Interlayer Shear

In the process of underground cavern excavation, the existence of the interlayer shear zones or large faults often makes the surrounding rock tend to be unstable or even deformed. Under the influence of interlayer shear zone C2, different degrees of deformation and failure occurred in many parts during the excavation of the Baihetan left bank underground powerhouse. Based on field monitoring and numerical calculation, this paper studies the deformation and failure characteristics of the rock mass with C2 in the whole excavation process and the failure mechanisms are analyzed. The results show that C2 has poor mechanical properties. In the process of excavation, it mainly induces two failure modes: rock collapse and shear deformation, which specifically leads to rock collapses, large deformation and shotcrete cracking in the main powerhouse, and shear deformation in the omnibus bar caves. In addition, the similarities and differences between this study and other studies on the deformation and failure of surrounding rock of underground powerhouse in recent years are discussed, and the relevant treatment measures for C2 are given. The above research results can be a reference for other related studies.

Deformation and failure of a film/substrate system subjected to spherical indentation: Part II. Prediction of failure modes in a thin TiN film deposited on a compliant elastic substrate

2006 ◽  
Vol 21 (3) ◽  
pp. 783-790 ◽  
Author(s):  
S. Math ◽  
V. Jayaram ◽  
S.K. Biswas
Keyword(s):  
Film Thickness ◽  
Failure Modes ◽  
Normal Load ◽  
Real Life ◽  
Plastic Substrate ◽  
Spherical Indentation ◽  
Elastic Substrate ◽  
Transform Method ◽  
Deformation And Failure ◽  
Elastic Film

We have demonstrated previously, using nanoindentation, that the film thickness and substrate plasticity, the important two external variables in the film layer, control the failure of the film in a mutually exclusive way. In this work, we used a non-iterative Hankel transform method to analyze the stresses in an elastic film bound to an elastic substrate by a no-slip boundary condition and subjected to a Hertzian traction. We vary the substrate compliance by two orders of magnitude to generate interfacial mismatch stresses, which mimic the corresponding changes found in a real-life elastic film on an elastic-plastic substrate when the hardness of the substrate is changed. The analysis is found to reproduce faithfully the experimental trends, which showed that normal load and interfacial stresses generated by strain mismatch drive different modes of fracture depending on the film thickness in a mutually exclusive way. This validation paves the way for this theoretical technique to be used to design multilayered film structures.

Comment on “Plastic deformation and fracture behavior of a Fe-modified Al3Ti-base L12 intermetallic alloy” [J. Mater. Res. 6, 957 (1991)]: The importance of specimen length-to-width ratios and end constraints in compression testing of brittle and semibrittle materials

1992 ◽  
Vol 7 (7) ◽  
pp. 1956-1959 ◽  
Author(s):  
David H. Zeuch
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Compression Tests ◽  
Specimen Length ◽  
End Effects ◽  
Deformation And Failure ◽  
Test Configuration ◽  
Pressure Sensitive ◽  
End Conditions ◽  
Test Pressure

Specimen length-to-diameter ratios and specimen/platen end conditions are important to interpretation of, and comparisons between, uniaxial compression tests on brittle materials. When differing l:d ratios and specimen/platen end conditions are used to test pressure-sensitive materials, observations may not be readily comparable owing to the different and nonuniform triaxial stress states. Specimens of brittle Fe- and Ni-modified Al3Ti intermetallic alloys having relatively low and different l:d ratios were tested in compression by Gengxiang et al. and Turner et al., respectively. Qualitative observations on the macroscopic deformation and failure modes (shear failure and distributed microcracking) indicate that the alloys are pressure-sensitive and that the results were possibly complicated in differing degrees by test configuration. Thus, direct comparison of these results with those obtained earlier for Al3Ti by Yamaguchi et al., who used a significantly greater l:d ratio, may not be altogether useful. Approaches to minimizing end effects are reviewed.

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