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Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to research the influence of the web deflection on the bend-twist coupling characteristics of large wind turbine blades, the CAD model of NREL 5 MW blade is established based on NX secondary development, the aerodynamic loads of the blade are obtained by CFD method, the blade bendind angle and twisting angle are solved by the node displacement method to analyze the influence of web deflection for bend-twist coupling blade. The results show that the offset web helps to achieve the bend-twist coupling of blades. Under the action of aerodynamic load, the bending and twisting angle both increase along spanwise direction of blade gradually, and reach the magnitude at the tip of the blade; in forward bias, negative correlation between twist angle and offset, reverse bias is the opposite; positive bias blades bend-twist coupling coefficient is decreasing trend with the increase of deflection angle, reverse bias blade are greater than the conventional blade.

To solve the problems of alignment for launch container loading in field-artillery rocket, a novel end-effector, i.e., a swing-compliant hook, is proposed, whose structural parameters are optimized. First, the theoretical model describing the performance of the swing-compliant hook is established based on the node displacement method. The static displacement, static stress, and swing curve of the swing-compliant hook are analyzed by MATLAB, which verifies the rationality of the model. Then, the main structure parameters on the performance of the swing-compliant hook are obtained by using the experimental design method. Additionally, a response surface model characterizing the comprehensive performance of the swing-compliant hook is established. The optimization results show that when the length and the installation height of the compliant mechanism are 90 mm and 23 mm, and the end height of the lifting hook is 110 mm, the swing-compliant hook has an excellent performance in docking, lifting, transferring, and locating.

Abstract: Plasticity induced fatigue crack closure simulations were performed using a three-dimensional finite element analysis of a single edge-cracked tension specimen under constant amplitude loading and load ratio R =0. Four different methodologies were considered to assess fatigue crack closure: (a) a node displacement method monitoring the first and second nodes behind the crack tip, (b) a contact stress method, (c) the traditional compliance offset method, and (d) the adjusted compliance ratio (ACR) technique. The evolution of crack driving force was compared in terms of , where ΔKeff and ΔK are the effective and applied stress intensity factor ranges, respectively. The node displacement method using the first node behind the crack tip and the contact stress method produced the lowest levels of U. Larger U levels were obtained from the node displacement method using the second node behind the crack tip followed by those from the compliance offset technique. The ACR methodology provided the highest U values for the range of applied loading considered in this study. [Copyright &y& Elsevier]