力-位移混合控制方法在大型多功能试验加载系统拟静力试验中的应用

Application of force-displacement hybrid control method in quasi-static tests of a multi-functional testing system

为了满足结构试验试件尺寸越来越大、边界条件越来越复杂的需求,国内外多家高校和科研机构都开发了大型多功能试验加载系统,对试验系统的精确加载控制是保证试验顺利进行和取得准确试验结果的关键。通过介绍国内外现有的一些大型多功能试验加载系统,针对哈尔滨工业大学结构与抗震试验中心的大型多功能试验加载系统压剪拟静力试验的竖向加载控制方法展开研究;提出应用力-位移混合控制法实现竖向力加载控制,基于MTS控制系统给出具体实施方案,并通过试验对比传统力控制方法与基于力-位移混合控制法的控制效果。研究结果表明:传统力控制方法虽然能很好实现稳定的竖向力,但很难保证试件的压剪受力状态;而力-位移混合控制法不但可以精确实现轴向力的加载控制,还能确保试件的压剪受力状态;基于力-位移的混合控制法对于该类加载试验系统的竖向力加载控制具有通用性,在大比例尺柱、墙等试件的压剪试验中具有广阔的应用前景。

In order to investigate the aseismic performance of structures more precisely,a number of multifunctional structural testing systems are developed around the world in recent years. The testing systems are available for large-scaled or even full-scaled structural testing specimens and their flexible loading boundary conditions. The accurate control of loading facilities is the key to guarantee the smooth moving of specimen and the accuracy of testing results.Firstly,the existing multi-functional structural testing systems were briefly introduced and their control problems were pointed out. Then,a failed quasi-static test was presented. By analyzing the causes of failure,a force-displacement hybrid control method was proposed, it was a solution to simultaneous achievement of target vertical resultant force and synchronous displacement-controlled loading. The implementation procedure for the above mentioned control strategy was also illustrated. Finally,a successful quasi-static test was performed to verify the effectiveness of the proposed hybrid control method. It was shown that by applying the hybrid control strategy,the expected control objectives can be well realized,more accurate results of quasi-static tests for large-scaled column and wall specimens can be guaranteed.