染雾Finite element analysis of dynamic structures 篇一
Finite element analysis (FEA) is a powerful computational tool used to analyze the behavior of complex structures under various loading conditions. In this article, we will discuss the application of FEA in the analysis of dynamic structures.
Dynamic structures are those that are subjected to time-varying loads or experience significant vibrations. Examples of dynamic structures include bridges, aircraft wings, and earthquake-resistant buildings. The behavior of these structures under dynamic loading conditions is of great importance in ensuring their safety and performance.
FEA allows engineers to simulate the behavior of dynamic structures by dividing them into small, interconnected elements and solving the governing equations of motion. These equations take into account the material properties, boundary conditions, and external loading, and provide valuable insights into the structural response.
One of the key advantages of FEA in the analysis of dynamic structures is its ability to accurately predict the natural frequencies and mode shapes. Natural frequencies are the frequencies at which a structure tends to vibrate when excited, while mode shapes describe the pattern of vibration at these frequencies. By analyzing the natural frequencies and mode shapes, engineers can identify potential resonance issues and design the structure to avoid them.
FEA also allows for the analysis of dynamic response under transient loading conditions. Transient loads are time-varying loads that can occur suddenly, such as an impact or an earthquake. By simulating the response of a structure under these transient loads, engineers can assess its ability to withstand such events and make necessary modifications to improve its performance.
Additionally, FEA can be used to analyze the fatigue life of dynamic structures. Fatigue is the phenomenon of progressive and localized structural damage that occurs when a structure is subjected to repeated loading and unloading. By simulating the cyclic loading conditions and analyzing the stress distribution, FEA can predict the fatigue life of a structure and help engineers optimize its design to ensure its longevity.
In conclusion, FEA plays a crucial role in the analysis of dynamic structures. Its ability to accurately predict the natural frequencies, mode shapes, transient response, and fatigue life provides engineers with valuable insights into the behavior of these structures under various loading conditions. By utilizing FEA, engineers can optimize the design and ensure the safety and performance of dynamic structures.
Finite element analysis of dynamic structures 篇二
Finite element analysis (FEA) is a widely used computational method for analyzing the behavior of structures under dynamic loading conditions. In this article, we will explore the specific challenges and considerations involved in the FEA of dynamic structures.
One of the main challenges in the FEA of dynamic structures is the accurate modeling of the dynamic loading. Dynamic loads can vary in magnitude, frequency, and direction, making it crucial to capture their true behavior in the analysis. This requires careful selection of appropriate load models and accurate representation of the time-varying nature of the loads.
Another important consideration is the selection of appropriate element types and mesh sizes. Dynamic structures often exhibit localized stress concentrations and complex vibration patterns, which can be better captured with refined meshes and higher order element types. However, this comes at the cost of increased computational time and memory requirements.
Furthermore, the accurate representation of material properties is crucial in dynamic FEA. Dynamic structures may exhibit nonlinear material behavior, such as plastic deformations or time-dependent viscoelasticity. It is important to accurately model these material behaviors in order to obtain reliable results.
The time step size used in the analysis is also a critical factor. In dynamic analysis, the time step should be small enough to capture the high-frequency components of the response accurately. However, using excessively small time steps can lead to increased computational costs without significant improvements in accuracy. Therefore, a balance between accuracy and computational efficiency must be struck.
Post-processing and interpretation of the results from dynamic FEA also pose challenges. Visualization of the vibration modes, identification of critical locations, and assessment of the dynamic response require specialized techniques and tools. Engineers must be able to interpret the results and make informed design decisions based on them.
In conclusion, the FEA of dynamic structures presents unique challenges that require careful consideration and expertise. Accurate modeling of dynamic loads, appropriate selection of element types and mesh sizes, accurate representation of material properties, and careful post-processing are all crucial in obtaining reliable results. By addressing these challenges, engineers can gain valuable insights into the behavior of dynamic structures and make informed design decisions.
Finite element analysis of dynamic s 篇三
Finite element analysis of dynamic stability of skeletal structures under periodic loading
Abstract：This paper addresses the dynamic stability problem of columns and frames subjected to axially applied periodic loads. Such a structure can become unstable under certain combinations of amplitudes and frequencies of the imposed load acting on its columns/beams. These are usually shown in the form of plots which describe regions of instability. The finite element method (FEM) is used in this work to analyse dynamic stability problems of columns. Two-noded beam elements are used for this purpose.The periodic loading is decomposed into various harmonics using Fourier series expansion. Computer codes in C++ using object oriented concepts are developed to determine the stability regions of columns subjected to periodic loading. A number of numerical examples are presented to illustrate the working of the program. The direct integration of the equations of motions of the discretised system is carried out using Newmarks method to verify the results. 作者： Author： THANA Hemantha KumarAMEEN Mohammed 作者单位： Department of Civil Engineering, National Institute of Technology, Calicut, Kerala 673601, India 期 刊： 浙江大学学报A（英文版） ISTICEISCI Journal： JOURNAL OF ZHEJIANG UNIVERSITY SCIENCE A 年，卷(期)： 2007,8(2) 分类号： U448.25 Keywords： Finite element analysis Dynamic stability Mathieu-Hill equation 机标分类号： O34 V21 机标关键词： dynamic stabilityfinite elem
