Characteristics of Shock Waves and its Effect on Structural Elements
"Types of dynamic loads that might face an engineer during any design procedure vary. One of these loads that sparked my interest to study is the explosion's pressure on buildings which is in other words the blast load. This thesis will be discussing the behavior of a blast wave in general and how the structural elements would respond to it.
The interaction of a blast wave with objects will be explained precisely. Numerical expressions that were derived by well known researchers in this domain will be added. This thesis concentrates on a very important phenomenon for any structural engineer which is the spalling of concrete, and a physical property for materials known as the mechanical impedance.
It also studies the possibility of using a finite element method as a tool for predicting the dynamic response of blast loaded reinforced concrete beams. In this study, the advanced software, ABAQUS is used in order to model materials and consider the material nonlinearity, stiffness degradation and strain rate effects. Moreover a single degree of freedom analysis was provided to achieve more accuracy in the model verification process. Experimental results for several beams under explosion were chosen to be modeled and verified in ABAQUS.
Several conclusions were made based on the verified models. A numerical expression that was derived from the experimental study on beams was studied and discussed. The damping effect on structural element facing blast loading was also studied, and graphs showing how the total energy dissipated are provided. At the end an Iso-Damage curve, showing the force-impulse combinations that cause damage for the structural element, is drawn.
Further research should involve doing real experiment on beams in order to study in detail the behavior of different types of structural elements, and to develop numerical formulas to help us to figure out all the parameters related to such an analysis. Considering that this field is still new and our region is facing a serious threat which is terrorism. Therefore buildings need to be protected correctly to withstand this type of sudden danger, and that's what I hope to achieve in my PHD studies in the future."
Ali Hussein Jahmi
Dr. Yehia Temsah