دانلود رایگان مقاله تحلیل سختی لامینیت موجدار تحت تغییر شکل بزرگ

Abstract

This paper presents a detailed investigation about the geometric non-linear stiffness behavior of corrugated laminates in six different load cases. The considered tensile, bending, and shear load cases allow the modeling with a unit-cell approach assuming a generalized plane strain state. The torsional load case is more complex. There the mechanical response depends on the number of unit-cells and the width of the samples in case of geometric non-linearities. We first identify the load cases that show a non-linear stiffness response under large deformation. Then the non-linear behavior is analyzed in detail using numerical simulation and we aim for mechanical explanations to describe the non-linear behavior. The FE simulations of the torsional load case are validated using experiments with 3D printed samples.

5. Conclusion

In the present paper we investigated the geometric non-linear behavior of corrugated laminates in six different loading situations. In load case 1, 3, and 4 we found that material strength is exceeded before geometric non-linearities can occur. All the non-linear stiffness curves show a very progressive behavior with a knee where the stiffness changes. For load case 2, tensile loading in ydirection, the stiffness response is highly non-linear due to large deformations. In load case 5, bending about the x-axis, the stiffness remains linear until self-contact between the unit-cells occur. At this point the stiffness increases. In load case 6, the large deformations also resulted in geometric non-linearities. Due to its complexity load case 6 was investigated numerically and experimentally. The experiments are very robust and reproducible and agree very well with the FE simulation. We observed that the qualitative non-linear stiffness response mainly depends on the corrugation amplitude. These results can be used in design processes where large deformations might occur, such as morphing wings, to estimate whether linear modeling is sufficient or geometric non-linearities have to be considered. We can conclude that non-linearities have to be taken into account for structural materials in load case 2 and 6, and in load case 5 if self-contact occurs. To increase the applicability for design purposes, we plan to model combinations of the different load cases and conduct parametric studies in future work.