应用人工神经网络理论建立热粘塑性材料的本构关系

本文将人工神经网络（ＡＮＮ）用于建立热粘塑性材料的本构关系，意在探索出一种描述材料变形力学行为的新方法。文中给出了应用人工神经网络建立热粘塑性材料本构关系的ＢＰ模型和学习算法过程，并应用于４５号钢在高温和高速变形条件下的流动应力计算。计算结果与实测结果比较表明，二者吻合良好。因此，应用人工神经网络建立热粘塑性材料的本构关系具有重要的工程应用价值。     

一种用粘塑性材料作传力介质的板料半模成形新工艺

用固态的橡胶、聚氨酯，液态的水，油及气态的压缩空气、膨胀气体等材料作为传力介质的板料半模成形工艺，促进了板料成形技术的发展，虽各自的特点构成了相应的适用范围，但亦存在着许多不足。本文通过对半模成形过程的研究，提出了一种新型的半模成形工艺－用粘塑性材料作为传力介质，通过对模具结构，板料成形性、产品的尺寸精度、表面质量及料厚均匀性等方面的研究分析表明，该工艺比气态，固态及液态材料为传力介擀的关模成形工     

碗形件的半模成形工艺

本文介绍了用粘塑性材料为传力介质的板料半模成形工艺成形摩碗零件的工艺过程，模具结构，零件质量等问题。实验结果表明，采用半模成形工艺不仅成形了合格的摩擦碗零件，且较常规工程模具本低，零件尺寸精度高，表面质量好。     

综合材料

近年来工业设计的方法与技术与家具设计的结合越来越紧密,其中一个非常典型的特点就是塑性材料与木的结合。     

斜井在表土段时底板承载力的初探

针对斜井在表土段出现的井壁断裂、开缝、顶底板及两帮强烈相对移近的情况，用太沙基公式建立了斜井底板承载力计算模型，并针对斜井底板倾斜的情况对计算模型作了一些修正。根据计算模型定性分析了影响底板承载力的参数，为提高底板承载力提供了理论依据。     

ADAPTIVE RIGID-PLASTIC MESHLESS GALERKIN METHOD AND ITS APPLICATION IN ANALYSIS OF EXTRUSION PROCESSES

Under the hypothesis of the rigid-plastic material,specific efforts are placed on the deve-lopments of the key simulation techniques of the meshless Galerkin method because of the complexity of the deformation process as well as the generality and atomization of the simulation procedures for non-steady state large deformation plastic processes,therefore,an adaptive rigid meshless Galerkin method is developed. The influence domain control method is used in the least square approximation by dynamic evaluation of the magnitude of the influence domain and the effective control of the amount and the positions of the points in the least square approximation in order to improve approxi-mation precision. The amount of the Gauss integration points in the discrete domain is maintained in a considerable magnitude in order to ensure the integration precision in the discrete domain. The length of the frictional boundary of the plastic deformation process may be getting longer when its deforma-tion is getting severe. Thus,the densities of the boundary points of some places get lower. The adap-tive boundary points setting method is employed to improve the approximation precision of the boundary points and enhance the constraint of the boundary condition by adaptive control of boun-dary point density. Some typical extrusion processes are analyzed,detail simulation results such as the deformation field,velocity field,effective strain field,effective strain rate field,the volume loss curve and load-stroke curve are obtained. The effectiveness of the method developed is demonstrated and the precision of the meshless simulation is proved by overall comparison with the results obtained by using the commercial software deform.     

道康宁借由新型材料推动LED市场

<正>美国道康宁公司日前针对成长快速的LED市场推出多种新型有机硅材料。道康宁以其凝胶、弹性体(elastomer)和树脂产品线为基础发展出的这些新材料包括了DOW CORNING~(R)EG-6301、DOW CORNING~(R)OE-6336及DOW     

Plastic equation of state determined by nano indentation

In order to characterize the plastic state of a deformed material,an indentation method to determine the plastic equation of state (PES) was developed.The work-hardening coefficient and the strain rate sensitivity coefficient of the plastic mechanic equation of state were determined by two kinds of indentation tests respectively.Therefore,the PES of materials under deformation can be obtained,and the plastic state of materials can be determined.     

粘塑材料中反平面Ⅲ型动态扩展裂纹尖端的渐近场

采用弹性－粘塑性模型对粘塑材料中反平面Ⅲ型动态扩展裂纹尖端的应力、应变场进行了渐近分析。假定应力有γ＾－δ幂函数奇异性时，得到了裂纹尖端应力、应变场的渐近方程。