摘要:船舶作为一种运输工具有着广泛的使用，所以对于其结构安全，人们也特别的重视。船舶上除了板材外，其余大部分都是可以简化为一些梁结构来处理，如骨材，纵桁等，振动是船舶建造航行时的一种正常现象，但不合理的振动会对船舶结构产生严重的破坏，长时间的振动也会对船舶产生疲劳破坏，研究振动和载荷识别对保障船舶安全有重要的作用。在实际工程中，动载荷识别也是一种非常重要的技术。

本文中对简支梁作为研究对象对其进行探讨，首先求解正向响应问题。载荷分为两种类型，一种为分布周期激励载荷，另一种为单点或多点周期激励载荷。不同的激励，正向求解使用不同的方法，单点以及多点用模态分析法，求解各介模态响应并求和得到频响函数，根据频率响应函数求解在单点或多点周期激励下，各个激励点响应随时间变化的图像。分布简谐载荷先设一个响应方程形式，将其带入振动微分方程，化简将其作Laplace变换，最后根据简支梁边界条件，将其代入微分方程，求解出响应方程。后面关于载荷识别，本文研究了单点以及多点周期激励下的载荷识别，主要方法为频域法中矩阵求逆法。对于连续载荷的识别，主要运用了切比雪夫多项式，本文对此作了简要的研究，最后对其进行了仿真，并对比仿真识别结果。对于识别结果，最后做了简要的分析。并考虑了载荷幅值识别模型的成立条件以及使用，并将模型进一步扩展成连续分布载荷，应该如何解决做了简要的思考。

关键词:响应，载荷识别，单点周期载荷，频域，结构动力学

ABSTRACT:Ships as a means of transport has a wide range of use, so people pay much special attention to its structural safety.Most of the rest of the ship can be simplified for some beam structures, such as aggregates, girders, etc.Vibration is a normal phenomenon when the ship is sailing, but unreasonable vibrations can produce the ship's structure Serious damage, long-term vibration will also produce fatigue damage to the ship, the study of vibration and load identification to protect the safety of the ship plays an important role. In actual engineering,dynamic load identification is also a very important technology.

In this paper, we take the simple beam as a research object to explore it. Firstly,we solve the positive response problem. The load is pided into two types,one for the distribution cycle to stimulate the load, and the other for the single or multi-point periodic excitation load.Different excitation,positive solution using different methods,single point and multi-point modal analysis method to solve the various modal response and sum to get the frequency response function,according to the frequency response function to solve the single point or multi-point cycle. Each of the excitation points responds to an image that changes over time.The harmonic response is first introduced into a vibration equation,which is transformed into a Laplace transform.Finally,according to the beam boundary condition,it is substituted into the differential equation to solve the response equation.In this paper,we study the load identification under single point and multi-point period excitation.The main method is the matrix inversion method in frequency domain method. For the identification of continuous load,the Chebyshev polynomial is mainly used,this paper makes a brief study of this,and finally simulates it and compares  the simulation results.

Finally we made a brief analysis about the identification of the results,and . I takes into account the establishment of the load amplitude recognition model and the use of the model,and further expand the model into a continuous distribution of load.

Key  words:  response,load  identification,single  point  periodic  load,  frequency domain,structural dynamics