基于力和位移混合控制的多自由度结构拟静力试验方法研究

Force-displacement mixed control method for quasi-static tests of structures with multiple degrees of freedom

多自由度结构拟静力试验中需对各自由度按照特定的力比例模式进行加载,因此力控制加载自然成为多自由度结构拟静力试验的选择。然而,结构进入倒塌阶段后承载力急剧下降,采用力控制加载的拟静力加载试验难以实施。为有效解决上述问题,提出一种适用于多自由度结构拟静力试验的力和位移混合控制方法。采用此混合控制试验方法既能够保持结构各自由度的受力符合特定的力比例关系,又可以保证在结构进入倒塌阶段后实施稳定的加载控制。基于MTS公司的Flex-Test IIm平台采用Visual BASIC语言开发了多自由度力和位移混合控制拟静力加载试验控制软件TMPTG,并进行了具体试验,验证了混合控制算法的有效性。

In quasi-static tests for structures with muhiple degrees of freedom, the forces applied to the structures commonly follow a prescribed force profile, so the loading with controlled forces becomes the natural choice. However, force control is not applicable any more when the bearing capacities of the tested structures decrease dramatically during the collapse stage. To this end, a force-displacement mixed control method is proposed to apply in quasi-static tests for structures with multiple degrees of freedom. By this method, the forces on each degrees can followed force profile and achieve the stable control of the quasi-static loading in the collapse stage. Based on the Flex-Test IIm platform of MTS Corporation, a test program called TMPTG using the mixed control algorithm is developed. Some tests are conducted and the effectiveness of the method is verified.