OpenSees-SNOPT Framework for Finite-Element-Based Optimization of Structural and Geotechnical Systems

The finite-element (FE) method is widely recognized as a powerful tool in modeling structural and geotechnical systems and simulating their response to static and dynamic loads. In addition, numerical optimization is commonly used in many engineering applications, such as structural reliability analysis, FE model updating, structural identification, and structural optimization. This paper focuses on the extension of Open System for Earthquake Engineering Simulation (OpenSees, an existing software framework for nonlinear FE analysis) using Sparse Nonlinear Optimization (SNOPT, a state-of-the-art numerical optimization software). The extended OpenSees-SNOPT framework is general and flexible and can be used to solve a wide range of FE-based optimization problems in structural and geotechnical engineering. It has several distinguishing features: (1) advanced capabilities in solving optimization problems involving complex structural/geotechnical engineering systems; (2) versatility in modeling a very wide range of structural and/or geotechnical systems; (3) computational efficiency; (4) flexibility to easily accommodate and benefit from new developments in FE structural modeling and analysis, computational optimization, and probabilistic modeling and analysis; and (5) capabilities of exploring new optimization-based problems and solution methods. The use of this coupled framework is illustrated through three representative application examples, i.e., a FE reliability analysis of a reinforced concrete frame, a FE structural optimization problem of an electrical transmission steel tower, and a FE model updating the problem of a geotechnical system.