In the resent years , our state invests much for important engineering projects , irrigation works , expressway , underground and so on . as huge engineerings deal with complex foundation condition , there are often poor foundation , and because the engineerings are very important , the their request for stress is more rigorous than common ones 近几年，国家投资建设了许多重要工程，水利水电工程，高速公路，地铁工程等等，由于大型工程涉及的地质条件会复杂些，往往会遇到软弱地基，由于工程的重要性，对于变形的控制要比一般工程严格一些。
Structure dynamic damage identification is a research field with a good perspective . in this paper , the method of using the structure multi - modal parameters as the network inputs in the damage diagnosis has a definite physical meaning , especially that measuring few modal steps to make the engineering application easily , both the theory and method are suitable to the average engineering structure 结构损伤识别是一个发展前景广阔的研究领域，本文研究的以结构多模态参数作为神经网络输入进行损伤识别的方法物理意义明确，需要测取的模态阶数较少，易于在工程实际中实施，其原理和方法适用于一般工程结构。
The solution existence for dynamic topology optimization of truss is explored from the engineering point of views : when the design variables ( section areas ) are continuous and their bound are not imposed , if there is no frequency constraint , the optimal solution always exists for a given optimization problem and contrarily , when the frequency constraint is considered , the frequency will become the key constraint and also the solution existence will be changed by the topology alteration 从一般工程意义上探讨了桁架结构动力学拓扑优化设计解的存在性：无固频约束时，设计变量连续且不考虑上限约束，则优化问题总是有解；考虑固频约束时，频率约束是是否有解的关键约束，并且改变结构拓扑形状可以改变解的存在性。
The system introduces 991 ultra - low frequency pick up , and takes the vibration signal as the simulation input of practical measurement , which makes the s ystem can measure the ultra - low frequency vibration of long , large , tall and flexible structures and the low frequency vibration of engineering and site 系统引入991型超低频拾振器，将其拾取的振动信号作为本系统实际应用测试中模拟输入，使系统可对长大高柔结构的超低频振动和一般工程及场地的低频振动进行测量。
On the standpoint of constraint design , this thesis first classifies die design constraints according to their features . based on the classification , and without losing general engineering sense , the thesis then proposes a die constraint information representation model , which uses templates as media and combines multiple knowledge representation methods , e . g . predicates , formulas , productions 本文从约束设计的角度出发，首先根据约束特点分类冷冲模设计约束，在分类的基础上和不失一般工程意义的前提下，给出以模板为载体，谓词、公式、产生式等多种知识表述方法相结合的冷冲模约束信息表示模型。
