Optimization approachedfor improvement of mismic performances of steel buildings and members

1.对单调和循环荷载作用下悬臂梁翼缘形状进行了优化，翼缘和腹板离散为壳单元。以塑性变形耗能最大为目标函数，给出了焊接截面塑性应变的约束条件。用一种称为模拟退火法的启发式方法对B-Spline曲线的控制点位置进行了优化。这种方法通过应用优化技术找到了实际可接受的最优形状。通过实验研究，验证了有限元分析的准确性。所提出的结构优化框架可应用于节点板、加劲肋等其他结构部件的优化设计。提出了钢框架在静、动力荷载作用下的多目标优化方法。构件的横截面属性选自Pre…更明确的可用部分列表。研究表明，通过模拟退火法、基于可行设计局部进行法的禁忌搜索等单点搜索启发式算法的分析次数较少，可以找到许多具有足够多样性的Pareto最优解。通过这种方法，可以有效地将优化技术应用于具有实际意义的问题。在宽翼型钢柱-梁节点中，为了防止梁翼缘集中力导致柱的局部破坏，常采用横向加劲肋。当梁翼缘宽度相对于柱的加强区较窄时，加强筋不能充分发挥作用。采用梁柱连接模型进行了荷载试验。试验结果表明，在以前的研究中建立的强度公式是准确的。对试件的应变分布和残余变形的测量证实了根据屈服线理论推导强度公式时所假定的破坏机制的有效性。较少

1. The shape of the flanges of a cantilever beam has been optimized under monotonic and cyclic forced deflections, where the flanges and web are discretized to shell elements. The objective function to be maximized is the dissipated energy by plastic deformation, and the constraints are given for the plastic strain at the welded section. The locations of the control points of the B-spline curve are optimized by a heuristic approach called simulated annealing. This way the practically acceptable optimal shapes have been found by application of optimization techniques. The accuracy of finite element analysis has been verified by carryitig out by experimental study. The proposed framework of structural optimization can be applied to tuning up other structural parts such as gusset plates and stiffeners.2. Multiobjective optimization methods have been presented for steel frames under static and dynamic loading conditions. The cross-sectional properties of the members are selected from a pre … More defined list of available sections. It has been shown that many Pareto optimal solutions with enough diversity can be found by moderately small number of analysis by single-point-search heuristics such as simulated annealing and tabu search based on local march of feasible designs. This way, it has been shown that optimization techniques can be efficiently applied to problems with practical importance.3. In wide-flange steel column-to-beam connections, transverse stiffeners are often used to prevent local failure of columns caused by concentrated beam-flange force. The stiffeners work insufficiently if the beam-flange width is rather narrow relative to the column stiffening region. Loading tests using the beam-to-column connection models were conducted. The test results revealed an accuracy of the strength formula developed in the previous study. Measurements of the strain distribution and residual deformation of the test specimens confirmed validity of the failure mechanisms assumed in deriving the strength formula based on the yield line theory. Less