Crush Strength of Aluminum 5052-H38 Honeycomb Materials under Combined Compressive and Shear Loads

The crush strength of aluminum 5052-H38 honeycomb materials under combined compressive and shear loads are investigated here. The experimental results indicate that both the peak and crush strengths under combined compressive and shear loads are lower than those under pure compressive loads. A yield function is suggested for honeycomb materials under the combined loads based on a phenomenological plasticity theory. The microscopic crush mechanism under the combined loads is also investigated. A microscopic crush model based on the experimental observations is developed. The crush model includes the assumptions of the asymmetric location of horizontal plastic hinge line and the ruptures of aluminum cell walls so that the kinematic requirement can be satisfied. In the calculation of the crush strength, two correction factors due to non-associated plastic flow and different rupture modes are considered. The results of the crush model indicate that as the shear stress increases, the crush strength decreases. The increase of shear stress also causes the wavelength of the fold to increase. In addition, the shear displacement of the fold increases as the shear stress increases. The results of the microscopic model give a fair agreement with those of the available experiments.