The elastodynamic bimaterial interface under mode I and mode II loading

2021 ◽  
Vol 225 ◽  
pp. 111031
Author(s):  
B. Gurrutxaga-Lerma
Author(s):  
Nicholas Aerne ◽  
John P. Parmigiani

The need for lightweight components and non-destructive fastening techniques has led to the growth of adhesive use in many industries. Modeling the behavior of adhesives in fastening joints can help in the design process to make an optimized joint. To optimize joints in the design process, the loading conditions, environmental conditions of service, thickness of bond, and bonding procedures all need to be refined for the adhesive of interest. However, in available technical data sheets of adhesives provided by manufactures there is a gap in what is sufficient to accurately model and predict the behavior of real-world adhesive conditions. This body of research presents the results of the effects of temperature, thickness, and working time on adhesive properties. These effects can be observed with test specimens from the loading modes of interest. The loading modes of interest are mode I and mode II loading for the current study. The specimen for mode I loading is the Double Cantilever Beam, and for mode II loading is the Shear Loaded Dual Cantilever Beam. The effect of temperature will be tested by testing each specimen at −20°C, 20°C, and 40°C. Two bond thicknesses for adhesive thickness effects were tested. The working time had a control group bonded in the recommended working time and an expired working time group where the specimens were not joined until 10 minutes had passed from the recommended working time. Triplicates of each specimen at the respective conditions were tested. The adhesive selected for this research was Plexus MA832. The results of the experiment show that adhesive factors such as temperature, thickness, and working time can have degrading effects on adhesive performance in mode I and mode II.


1989 ◽  
Vol 111 (1) ◽  
pp. 174-180 ◽  
Author(s):  
D. Singh ◽  
D. K. Shetty

Fracture toughness of polycrystalline alumina and ceria partially stabilized tetragonal zirconia (CeO2-TZP) ceramics were assessed in combined mode I and mode II loading using precracked disk specimens in diametral compression. Stress states ranging from pure mode I, combined mode I and mode II, and pure mode II were obtained by aligning the center crack at specific angles relative to the loading diameter. The resulting mixed-mode fracture toughness envelope showed significant deviation to higher fracture toughness in mode II relative to the predictions of the linear elastic fracture mechanics theory. Critical comparison with corresponding results on soda-lime glass and fracture surface observations showed that crack surface resistance arising from grain interlocking and abrasion were the main sources of the increased fracture toughness in mode II loading of the polycrystalline ceramics. The normalized fracture toughness for pure mode II loading, (KII/KIc), increased with increasing grain size for the CeO2-TZP ceramics. Quantitative fractography confirmed an increased percentage of transgranular fracture of the grains in mode II loading.


Delamination is the common failures of composite material attributed to various reasons, most importantly the potential stiffness degradation leading to small flaws and subsequently theypropagate, and it becomes essential to characterize the new materials for interlaminar fracture. For the present study Carbon /epoxy system of IM7/8552 was investigated under mode I and mode II loading. Material was formed into unidirectional laminates with Teflon inserts at its mid length. The specimens were machined according to ASTM standards, Tests were executed on a quasi-static Intron 8225, with load control at 5 mm/ min and 2 m/min for the mode -I and mode-II respectively. The strain energy release rate was found to be GIC=0.266 kJ/m2 and GIIC=0.687 kJ/m2 . Fiberbridging was prominently absent in the DCB samples Examination of the fracture surface by SEM at SAIF, in IIT{M) and the nature of the fracture surface revealed the typical failure mechanism pertaining to mode-I and mode-II failuremechanisms


2019 ◽  
Vol 227 ◽  
pp. 111330 ◽  
Author(s):  
Sota Oshima ◽  
Akinori Yoshimura ◽  
Yoshiyasu Hirano ◽  
Toshio Ogasawara ◽  
Kwek-Tze Tan

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