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71.
Locking‐free discontinuous finite elements for the upper bound yield design of thick plates
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Jeremy Bleyer Canh Van Le Patrick de Buhan 《International journal for numerical methods in engineering》2015,103(12):894-913
This work investigates the formulation of finite elements dedicated to the upper bound kinematic approach of yield design or limit analysis of Reissner–Mindlin thick plates in shear‐bending interaction. The main novelty of this paper is to take full advantage of the fundamental difference between limit analysis and elasticity problems as regards the class of admissible virtual velocity fields. In particular, it has been demonstrated for 2D plane stress, plane strain or 3D limit analysis problems that the use of discontinuous velocity fields presents a lot of advantages when seeking for accurate upper bound estimates. For this reason, discontinuous interpolations of the transverse velocity and the rotation fields for Reissner–Mindlin plates are proposed. The subsequent discrete minimization problem is formulated as a second‐order cone programming problem and is solved using the industrial software package MOSEK . A comprehensive study of the shear‐locking phenomenon is also conducted, and it is shown that discontinuous elements avoid such a phenomenon quite naturally whereas continuous elements cannot without any specific treatment. This particular aspect is confirmed through numerical examples on classical benchmark problems and the so‐obtained upper bound estimates are confronted to recently developed lower bound equilibrium finite elements for thick plates. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
72.
Advances in computation challenge established design approaches in architecture through a much deeper integration of form generation and materialisation. Tobias Schwinn , Research Associate at the Institute for Computational Design (ICD), University of Stuttgart, and Guest-Editor Achim Menges , Director of the ICD, introduce how the potentials and constraints of robotic fabrication can now be explored as generative drivers in agent-based design. This enables architectural innovation in unison with fabricability, structural capacity and spatial performance, as demonstrated by the Landesgartenschau Exhibition Hall in Schwäbisch Gmu"nd, Germany, the world's first building with a robotically fabricated segmented timber shell as its primary structure. 相似文献
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《钢结构》2013,(4):80-81
尽管不锈钢和碳素钢的力学性能有本质区别,然而,现行规范规定不锈钢连接设计时仍基本遵循碳素钢的设计准则,仅在此基础上稍作修改。对于常见的角钢单肢与加固板连接的情况,EN1993-1-4以及SCI/欧盟不锈钢设计手册对不锈钢的设计规定,直接采用了EN1993-1-8对碳素钢净截面承载力的设计规定,且未作任何修改。对单肢与加固板采用单排螺栓连接的L型不锈钢的净截面承载力进行了研究。建立奥氏体不锈钢的数值模型,并利用现有的试验结果对其进行了验证。这些模型随后用于进行参数研究。最后,基于研究结果对L型不锈钢净截面承载力的设计方程进行了修正,并通过统计分析验证了该方程可靠性。 相似文献
75.
通过6根挤扩支盘桩的静载试验和桩身应力及桩端反力测试试验成果,分析挤扩支盘桩在竖向荷载下的变形受力特征,给出了对工程实践有指导意义的结论。 相似文献
76.
采用12.7 mm穿甲燃烧弹对不同厚度的Ti-6Al-4V钛合金板进行厚度效应试验,研究钛合金板厚度对其防护能力的影响。采用等重钢总穿深及防护系数的方法考核其抗弹性能。结果表明,钛合金板抗小口径枪弹(12.7 mm穿燃弹)板厚在10~30 mm间厚度效应呈现正效应。 相似文献
77.
通过VB软件采用常用的逐板计算法,运用VB软件强大的运算功能,结合计算机辅助计算的思路,给出了乙醇-正丙醇二元理想物系筛板精馏塔的理论板数和总板效率的求解方法,计算过程智能化、操作简便、结果准确,免去了粗糙、繁琐、耗时的手工计算,该方法对化工原理的教学有重要的意义。 相似文献
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Lei Xing Yuanxiang Xu Željko Penga Qian Xu Huaneng Su Weidong Shi Frano Barbir 《American Institute of Chemical Engineers》2020,66(6):e16957
An easily machined novel flow field with controllable pressure gradient across adjacent channels was designed and a two dimensional, across-the-channel, two-phase model was developed to study the gas transport and water removal of the novel configuration. The effect of channel-rib width ratio, GDL thickness and pressure gradient on the profiles of oxygen concentration and water saturation within the GDL were investigated. Special attention was paid to the mechanisms of the promoted mass transport and water removal rates under a pressure gradient. The model was validated by experiments with various channel-rib ratios and GDL thicknesses at different operating pressure. The results revealed that, oxygen concentration was increased, and the water saturation was reduced under the rib with a pressure gradient generated across the adjacent channels. The optimal pressure gradient is between 0.1 to 0.2 atm for the studied channel geometry and configuration. The mechanisms of the improved cell performance were elucidated. 相似文献
80.