The Analysis And Research On Dynamic Response Of Frame Structures Under Blast Shocks

In the fields of modern engineering structures, as a consequence of terrorist activities and local turmoil, engineering structures are usually suffer from the blast shocks. If the blast loads were loaded on the structure, it will cause damage to the structures because of strong vibration. Furterhmore, there will be a holistic collapse due to local members failed which are under the intense impact action. Therefore, studying the structural dynamic response under the blast shocks is highly valuable for application. Dynamic response and collapsing process under blast shocks are obtained in this paper on basis of a plane RC framework numerical simulating by ABAQUS dynamic finite element software. Then for the process of collapse, increasing the redundancy degree by changing the structural system is applied to improve the structures'ability of collapse-resistant. In the end, the structural dynamic response under the blast shocks is used to analysis the modal parameters by HHT which is a signal processing method. This paper has mainly introduced the following aspects:(1) Summarizing the present situation of structures'collapse-resistent study at home and abroad, introducing the methods of collapse-resistent which are available today, and making a comprehensive review to the application of HHT in analysis of structures.(2) The basic characteristics of blast were analyzed and summarized, on the basis of the blast wave parameters, the relationship between the blast peak pressure and duration of the weight of detonator and explosive distance were ascertained, the triangle-based blast model which is on the basis of duration to and peak pressure Pso is given, and it was applied to the ABAQUS dynamic finite element method.(3) ABAQUS dynamic finite element method was used to numerical simulate a three-story and two-bay plane RC framework which is under blast loads, the dynamic response and collapse process of the plane framework under blast loads is obtained. For dynamic response and collapse process, the factors affecting the framework's capacity of blast-resistant and collapse-resistant is analyzed, and the concept of redundancy degree is imported. At the same time, increasing the redundancy degree by changing the structurel system method was used to improve the structural model, the results show that increasing the structural redundancy degree can be a very good suppression of the collapse of the structure, and so it effectively improved the capacity of blast-resistant and collapse-resistant of the structure. At last, the dynamic reponse of space RC frame under blast loads was calculated and analyzed, the axial compression ratio and dense column frame structure system for affecting the capacity of collapse-resistant was discussed at last.(4) This paper has studied the basic theories and methods of the HHT transform, and proved its superiority in dealing with signals by simple example. Then it analyzed and identified the modal parameters of the dynamic response of frame structural under blast loads by HHT with Butterworth Filter and Random Decrement Technique method. The results showed the anastomoseness of the HHT method and ABAQUS finite method in get hold of the structural parameters with certain limits.