Then an efficient and more accurate nonlinear finite element procedure based on the plastic node method ( pnm ) by combining elastic large displacement analysis theories with a plastic hinge model is presented to analyze the ultimate strength , directly accounting for the geometrical and material non - linearity and the influence of initial deformation and residual stress 然后采用塑性节点法，考虑结构的几何非线性和材料的非线性双重以及各缺陷因素影响，分析了不对称船体结构的极限强度。通过与实验值的比较，说明简化方法与塑性节点法都能较准确预报极限强度。
The choice of laser output window height is relation to many factors , such as pressure loading , thermal loading , yield stress , influence on wavefront , failure by fatigue . spherical windows can endure higher laser intensity . however , it brings some phaseshifts , which connect with laser windows parameters 激光器输出窗口厚度的选取与压力载荷、热载荷、材料极限强度、厚度对波前的影响、材料疲劳等多种因素有关，由于球壳窗口能承受较高的功率密度，但窗口本身带来相移，该相移大小与窗口参数有关，根据位相均方根值选择球壳窗口参数。
In this paper , torsional - flexural buckling of single - angle members is researched deeply and systematically by ultimate strength theory and general fem analysis software ansys , and is contrasted with some codes , as a result the simple and practical formulas for stability coefficient are recommended for design purpose 本文采用极限强度理论和通用有限元分析软件ansys ，系统深入地研究了单角钢轴心受压构件的弯扭失稳，并与多本规范进行了对比分析；在此基础上提出简单实用的稳定系数计算公式，以便工程设计参考。
On the basis of the concept of combination of action effects of modem prestressed concrete structures proposed by the authors , the ultimate limit states design proposals of normal section of prestressed concrete structures considering the effects of secondary moment and secondary axial force are presented in the paper 在作者提出的现代预应力混凝土结构设计荷载效应组合建议的基础上，给出了合理考虑次弯矩和次轴力影响的各类预应力混凝土结构正截面极限强度设计计算建议。
Pre - stressed steel structure , a new kind of structure in which combined pre - stress with steel structure , can take full advantage of the elastic strength of steel , and multiple pre - stressed steel structure can repetitively make full use of the elastic strength of steel , thus it can enhance the structural capacity and further improve the rigidity of structure , proving that it is more economic than single pre - stress . therefore , it is both theoretically and practically important to conduct in - depth research on multiple pre - stressed steel structure 预应力钢结构是一种将预应力与钢结构相结合的新型结构，预应力钢结构通过施加预应力以充分利用钢材弹性范围内强度，而多次预应力钢结构可以反复利用钢材弹性范围内极限强度，提高结构承载能力并进一步提高结构刚度，比单次预应力具有更好的经济效益，因此，对预应力钢结构进行深入研究具有重要的理论意义和工程应用价值。
The aims of this thesis are buckling and ultimate strength . its main content is as follows : emphasizes the significance and purpose of the research in buckling and ultimate strength , and reviewing the status in this field , and puts forward the research task ; analyzes and discusses the design formulations for the buckling strength of the ship plating , in which the influence of residual stresses , lateral pressure , cut - outs and rotational restrains is taken into account 本文以船体板的屈曲和极限强度为研究目标，主要内容有： ?指出研究船体板屈曲和极限强度的意义和目的，简要回顾了国内外的研究现状。并提出本文的研究内容； ?考虑残余应力、侧向压应力、开孔和扭转约束对于板格的屈曲强度的影响，讨论了各个因素影响下的板格的屈曲强度计算公式。
