In this paper, the mechanical properties of Nomex® paper coated with resin and composite Nomex® honeycomb sandwich structures (CNHSS) were obtained by tensile tests and flatwise tests respectively. The fundamental mechanical properties of the Nomex® paper were used as input materials parameters of finite element model generated at meso-scale level for the CNHSS, and the mechanical properties of CNHSSs were used to validate the numerical results. Based on the test and numerical results, the theoretical equations were modified to predict the flatwise compressive buckling strength and modulus of the CNHSS. The numerical and theoretical results clearly revealed that the CNHSS had two flatwise compressive elastic moduli. However, the flatwise test can only capture the second flatwise compressive elastic modulus due to manufacturing geometric defects of the cell walls. The numerical and test results showed that the manufacturing geometric defects of the cell walls showed little influence on the ultimate flatwise compressive strength. And the modified equation can predict the flatwise compressive buckling strength and modulus of the CNHSS with sufficient accuracy.

This paper presents an approach based on parameterized compliance for type synthesis of flexure mechanisms with serial, parallel, or hybrid topologies. The parameterized compliance matrices have been derived for commonly used flexure elements, which are significantly influenced by flexure parameters including material and geometric properties. Different parameters of flexure elements generate different degree of freedom (DOF) characteristic of types. Enlightened by the compliance analysis of flexure elements, a parameterization approach with detailed processes and steps is introduced in this paper to help analyze and synthesize flexure mechanisms with the case study as serial chains, parallel chains, and combination hybrid chains. For a hybrid flexure, the results of finite element (FE) modeling simulations are compared to analytical compliance elements characteristic. Under linear deformations, the maximum compliance errors of analytical models are less than 6% compared with the FE models. The final goal of this work is to provide a parameterized approach for type synthesis of flexure mechanisms, which is used to configure and change the parameters of flexure mechanisms to achieve the desired DOF requirements of types initially.

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