设置不锈钢U型阻尼器连续梁桥减震性能研究

不锈钢材料耐腐蚀性能强,具有良好的韧性、延性及较高的强屈比,在结构减震器领域有良好的应用前景。本文提出采用奥氏体型不锈钢S304与双相型不锈钢S2205制作U型金属阻尼器,组合板式橡胶支座用于连续梁桥减震设计。采用ABAQUS对不锈钢和高延性SN490B钢U型阻尼器的滞回特性进行对比,并以一座5跨连续梁桥为研究对象,计算比较了设置不锈钢U型阻尼器与SN490B钢U型阻尼器下桥梁在近断层地震动下的地震响应,结果表明:不锈钢U型阻尼器在平面内、平面外和双向加载下均具有稳定的滞回曲线,在相同的位移加载下S2205不锈钢U型阻尼器可提供更大的恢复力和等效刚度,但等效黏滞阻尼比略低;S304不锈钢U型阻尼器耗能能力与SN490B钢U型阻尼器相近,在±100mm位移幅值内可具有更小的等效刚度和更大的等效黏滞阻尼比;设置S2205不锈钢U型阻尼器可以更好地控制连续梁桥墩梁的相对位移,同时没有在桥墩底部产生更大弯矩及造成过大的损伤;设置S304钢U型阻尼器对墩梁相对位移控制能力要弱些,但对桥墩会有更好的保护作用。

金属橡胶隔振构件中不锈钢丝疲劳断裂的原因

采用激光扫描共焦显微镜观察了成分与302不锈钢基本相同的冷拉拔0.3 mm不锈钢丝的表面形貌特征,并用扫描电镜对其显微组织进行了观察,对用此钢丝制备的金属橡胶隔振构件进行了疲劳试验并对钢丝疲劳断裂的原因进行了分析。结果表明:该不锈钢丝表面存在较多微米量级的凹凸体,其表面粗糙度Ra为3.447μm;钢丝内部存在以硬质颗粒为核心,长轴方向与拉拔方向一致的梭形微孔洞;钢丝的疲劳裂纹均起源于表面,并且呈现多源特征,断口上的裂纹扩展区和瞬断区面积所占比例各半,裂纹扩展区有典型的舌形叠加波浪状疲劳辉纹,其形成与钢丝内部的梭形微孔洞有重要关系。

双曲型不锈钢管铅阻尼器性能研究

提出一种双曲型不锈钢管铅阻尼器,阐述了其构造与特点。采用ABAQUS有限元分析软件,对双曲型不锈钢管铅阻尼器和普通钢管铅阻尼器及设过渡段(A类构造)、不设过渡段(B类构造)的双曲型不锈钢管铅阻尼器进行对比分析。结果表明:双曲型不锈钢管铅阻尼器滞回曲线对称、饱满,在小位移下即进入屈服耗能,具有优异且稳定的耗能能力;当阻尼器初始屈服承载力相等时,双曲型不锈钢管铅阻尼器在更小的位移下进入较稳定的耗能状态,提供更大的稳定屈服承载力;A、B类构造的双曲型不锈钢管铅阻尼器均具有优异的力学性能,B类构造可降低不锈钢和铅芯的用量,简化加工工艺,提高其经济性。

Numerical study of the cyclic load behavior of AISI 316L stainless steel shear links for seismic fuse device

This paper presents the results of nonlinear finite element analyses conducted on stainless steel shear links. Stainless steels are attractive materials for seismic fuse device especially for corrosion-aware environment such as coastal regions because they are highly corrosion resistant, have good ductility and toughness properties in combination with low maintenance requirements. This paper discusses the promising use ofAISI 316L stainless steel for shear links as seismic fuse devices. Hysteresis behaviors of four stainless steel shear link specimens under reversed cyclic loading were examined to assess their ultimate strength, plastic rotation and failure modes. The nonlinear finite element analysis results show that shear links made of AISI 316L stainless steel exhibit a high level of ductility. However, it is also found that because of large over-strength ratio associated with its strain hardening process, mixed shear and flexural failure modes were observed in stainless steel shear links compared with conventional steel shear links with the same length ratio. This raises the issue that proper design requirements such as length ratio, element compactness and stiffener spacing need to be determined to ensure the full development of the overall plastic rotation of the stainless steel shear links.

不锈钢复合芯板剪切型摩擦消能器试验研究

为了解决传统摩擦消能器性能不稳定、价格昂贵等问题,研发了一种以双面不锈钢复合钢板为芯板的剪切型摩擦消能器。该消能器由复合钢板的不锈钢复层与石棉摩擦片组成耗能摩擦副,通过碟形弹簧和预压螺栓调节滑动摩擦面承受的面压力。提出了消能器极限位移、极限荷载和面压力等试验关键指标的计算方法。对3个消能器进行低周往复加载试验,考察其滞回曲线、耗能能力、极限破坏特征及疲劳性能。结果表明:采用不锈钢复合芯板的剪切型摩擦消能器构造合理,滞回性能稳定,耗能能力良好,抗疲劳性能优异。设计位移幅值下累积加载90次,消能器承载力不下降,滞回性能稳定。低周疲劳作用下芯板不同材质复合界面性能可靠,不锈钢复合板可用作摩擦消能器的芯板。