不锈钢复合钢材受压构件局部稳定和相关稳定性能及设计方法研究

Stainless-clad steels possess significant benefits in terms of both high-performance attributed to the stainless steel component and low-cost and high-strength provided by the conventional mild steel component. Therefore, they have great potential in practical application in steel structural engineering. Despite this, there is surprisingly little research reported in the literature on such advanced steels. Local buckling and interactive buckling behaviour of stainless-clad steel members subjected to compression is investigated thoroughly in this project through full-scale experimental research, numerical and theoretical modelling as well as parametric analyses. Fundamental principle of effects of specific material properties of the stainless-clad steel, initial imperfections like geometric imperfections, compound contact interface imperfections and welding-induced residual stresses is elucidated scientifically and quantitatively, and mechanisms of the whole buckling process of stainless-clad steel plates subjected to various loading conditions are clarified systematically. On this basis, local buckling behaviour as well as interactive buckling behaviour of columns under compression fabricated from such clad steel plates are further investigated. Accurate and robust unified design theories and calculation methods are developed for evaluating the buckling behaviour at the level of both plates and members. The research contents of this project are of practical significance and theoretical advanced values, and corresponding research outcomes may fill the gap for the research on elastoplastic plate buckling behaviour as well as local buckling behaviour of the clad steel structures world widely. It is also favourable for improving buckling theories and promoting the engineering application of the stainless-clad steel structures.

新型不锈钢复合钢材同时具备不锈钢的高性能优势和传统结构钢的强度与成本优势，因而在钢结构工程领域具有广阔的应用前景，但目前国内外相关基础研究十分有限。本项目综合采用足尺试验研究、数值和理论建模以及参数分析等手段，针对不锈钢复合钢材受压构件的局部稳定性能及相关稳定性能开展系统深入的研究；通过定量分析不锈钢复合钢材特有的材料弹塑性特征以及板件几何缺陷、钢材复合界面缺陷、焊接残余应力等初始缺陷的影响机理，系统阐释该类复合钢材板件在不同荷载条件下的弹塑性失稳全过程受力机理，并在此基础上深入研究受压构件的局部稳定性能和相关稳定性能；从板件到构件两个层面系统全面地制定统一稳定设计理论和计算方法。本项目的研究内容具有工程现实意义与理论前瞻价值，研究成果能够弥补国内外关于复合钢材板件弹塑性稳定和构件局部稳定基础研究的不足，并对于完善、创新复合钢材稳定设计理论、促进不锈钢复合钢材的实际工程应用具有重要意义。

不锈钢复合钢材作为一种性能优异的新型高性能复合钢材，适用于对耐腐蚀性能、建筑表现效果要求较高的工程结构，具有综合力学性能更优、施工简单周期更短、设计使用年限更长、全生命周期成本更低、综合社会效益更高等显著优势。不锈钢复合钢材在我国已有较成熟的产业基础和标准体系，在结构工程领域也已得到初步的成功应用，但国内外相关基础研究，尤其是构件层面的力学性能研究尚处于起步阶段。本项目通过力学理论分析、足尺试验研究、数值建模计算和参数对比分析，深入系统地研究了新型不锈钢复合钢材受压板件稳定、受压构件局部稳定和相关稳定的受力机理和性能，科学定量地阐释了不锈钢复合钢材的材料力学性能、受压构件的初始缺陷和几何参数等对板件弹塑性稳定、受压构件局部稳定和相关稳定性能的影响机理。在已有不锈钢复合钢材材料力学性能研究的基础上，补充进行了高应变率下的动态力学性能研究，形成了较为系统的全生命周期材料本构模型体系。使用三维扫描方法对受压构件进行了精确的初始缺陷测量，提出了基于真实缺陷与等效缺陷的数值建模方法，用于受压构件的局部稳定性能数值分析。通过板件弹塑性稳定理论研究、局部与相关稳定轴压试验及数值模拟，系统阐释了不锈钢复合钢材轴压构件的局部与相关失稳全过程力学机理，并建立了系统性的设计理论与计算公式。本项目的研究内容和成果具有理论前瞻性，将弥补国内外针对复合钢材结构受力性能研究的不足，建立相应的设计理论体系，并能够引领国际学术研究热点，推动双金属复合材料的研究和工程应用。