几何造型的自由畸变方法

几何造型是计算机图形学的重要研究内容，ＣＡＤ／ＣＡＭ的核心技术，现行的许多造型系统仅限于造型二次曲面及旋转曲面，没有自由曲面造型能力，本文研究的自由畸变为法，很容易扩展这些系统的自由曲面造型功能，该方法已成功地用于扩展ＭＯＶＩＥ．ＢＹＵ系统的自由曲面造型功能。     

方盒形带凸缘件的板料形状优化设计

本文用大变形刚塑性有限元模拟正方形板料在方冲头拉延下的凸缘变形过程，并以所获得的工件形状与金属流动方向为依据，对初始板料形状进行修正。对修正后的坯料形状进行二次模拟，获得了与给定凸缘形状基本吻合的拉延件形状。文中对不同凸缘圆角对极料优化形状的影响作了计算，讨论了在保证边界轮廓位置不变的条件下网格划分的方法。     

Application of Galerkin Method to Dynamical Behavior of Viscoelastic Timoshenko Beam with Finite Deformation

The motion equations governing the dynamical behavior of a viscoelasticTimoshenko beam with finite deformation are derived and simplified byGalerkin method. The viscoelastic material is assumed to obey thethree-dimensional fractional derivative constitutive relation. Thedynamical behaviors of the simplified systems with order 1 and order 2are numerically computed and compared by using the computational methodpresented by the authors. The dynamical behaviors of the systems areuniform qualitatively, but there is a little deviation quantitatively.And the truncated system with order 1 is safer than the one of order 2.It is also shown that the lower order system is reasonable. Theinfluences of the load parameter and the fractional derivative parameter(material parameter) on the deflection of the beam are consideredrespectively. The numerical methods in nonlinear dynamics, such as phasediagram, and Poincaré section, are applied to reveal dynamical behaviorsof the nonlinear viscoelastic Timoshenko beam. There are plenty ofdynamical behaviors, such as periodicity, bifurcation, quasi-periodicityand chaos in the dynamical system.     

小浪底水库调水调沙运用对大坝变形的影响分析

自2002年以来,小浪底水库汛前利用预泄汛限水位以上水量、腾空防洪库容的有利时机,连续5年进行集中调水调沙,获得了巨大的减淤效益.但在调水调沙期间,由于大流量下泄,水库水位下降较快,大坝变形明显增大,表现为水平位移向上游变化、垂直位移加速沉降变化的特点.监测分析结果表明,调水调沙运用不影响大坝安全稳定运行.     

薄板坯表面变形实验分析

对连铸薄板坯的坯壳表面变形的物理模拟实验方法进行了分析,提出一种"铜裹铅双金属"新实验方案,并对坯壳表面弯曲变形进行了分析.     

竹坑水库大坝安全鉴定分析

在竹坑水库大坝安全鉴定中,认真分析了该工程存在的主要问题,并针对大坝的结构稳定和渗流稳定作了详细的分析论证.     

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本文应用灰色关联分析方法,对70种不同类型和组成的钻井液,进行了两参数流变模式优选及评价。与现行方法比较的结果表明此方法与现行结果的吻合度高,并有新颖、数据要求量少、结论易于比较等优点。     

激光在塑性变形测量中的应用

本文将激光应用于云纹法，研究了缺口滚压强化后根部区域的位移场及应变分布规律。结果表明，本方法是提高塑性变形测量精度的有效手段。     

Energy absorption in splitting square metal tubes

This paper presents an investigation into the energy absorbing behaviour of axially splitting square metal tubes. Tubes 50 mm square with a variable thickness were pushed slowly against rigid pyramid shaped dies, which had various semi-angles. By pre-cutting 5 mm long slits at the four corners, the tube splits along the corners and curls outward with a certain radius at a constant force. In this energy dissipating system, there are three components: tearing energy, plastic deformation energy and frictional energy. Theoretical analysis of the three energy components is presented. Curl radius is also studied in detail. Good agreement between experiments and theory is obtained. The results show that tubes which both split and curl may be used as efficient, long stroke energy absorbing devices.