Research Initiation Award: Energy Based Damage Model and Procedure for Safety Analysis of Structural Systems In Steel Buildings

大多数工程结构的设计都是为了承载特定的服务或正常荷载。然而，计算机技术的最新发展创造了针对结构在其整个生命周期中预期的载荷进行设计的可能性。采用这种方法设计的结构将具有更好的耐久性、可维护性和易损性。为此，提出了一种基于能量的损伤模型，用于计算受损钢结构构件的剩余强度和刚度。剩余强度计算将利用构件的屈服、极限和破坏表面，这些表面将根据钢结构构件的广义力来定义。为了对结构系统进行安全评估，需要开发一种损伤分析计算机程序。为了提高安全分析程序的效率，采用随变形增加而变化的挠度形状，推导出损伤构件的刚度矩阵。将利用通过修改现有可靠性技术而开发的程序来评估结构系统的安全性。确定结构系统损坏和失效概率的整个过程将自动进行。上述发展将通过与现有实验和分析结果的比较来验证。所开发的损伤模型和安全分析算法将有助于根据期望的损伤和失效概率进行结构系统的设计。它们还将有助于钢结构系统的设计，在极端载荷下，将避免损伤集中和过早破坏。

Most engineering structures are being designed to carry specified service or normal loads. However, recent developments in computer technology have created a potential for design of structures against the loads expected during the whole cycle of their life. The structures designed by using this approach will have improved durability, maintainability and damageability. Herein, an energy based damage model will be developed for computation of residual strength and stiffness of damaged steel structural members. The residual strength computations will utilize yield, limit and failure surfaces of the member which will be defined in terms of generalized forces for steel structural members. For safety evaluation of structural systems, a damage analysis computer code is to be developed. For increasing the efficiency of the safety analysis procedure, a stiffness matrix will be derived for the damaged member by employing a deflected shape which varies with increasing deformations. The safety of structural systems will be evaluated by utilizing a procedure developed by modifying the existing reliability technique. The whole procedure of determining probabilities of damage and failure of structural systems will be automated. The above developments will be validated by comparisons with existing experimental and analytical results. The developed damage model and safety analysis algorithm will aid in design of structural systems based on desired probability of damage and failure. They will also aid in design of steel structural systems which, under the extreme loads, will avoid concentration of damage and premature failure.