基于应力归还法的单轴拉伸伺服控制试验系统的研制与应用

Development and application of uniaxial tensile servo test system based on stress feedback

根据岩石广义应力松弛特性试验研究的需要,自主研制了基于应力归还法的单轴拉伸伺服控制试验系统。该系统的(1)实现了应力归还法控制,既能单独控制加载传统的位移、应力,也可伺服控制应力-应变线性组合;(2)测量、控制系统采用硬件实现而非计算机软件,结构简单紧凑,系统动作反应时间短,性能稳定可靠,升级改造空间大;(3)控制及监测数据均采用模拟信号传输,试验过程控制及数据采集精度均较高;(4)采用高强度粘接剂直接拉伸,使试件完全处于被拉伸状态,能更真实地模拟工程实际中岩体的受力状态。采用该试验系统,对田下凝灰岩进行了拉应力条件下的广义应力松弛试验,试验结果表明,其具有较好的实用性和可靠性,为研究工程实际中岩石受拉应力作用下的广义应力松弛力学性质提供了新的试验方法及手段。

According to the need of laboratory study of the generalized stress relaxation characteristics of rock, an experimental system of uniaxial tension servo control, which is based on stress feedback take hardware devices as basis and transforms data recording and servo controlling to achieve the stress feedback method, is developed. The advantages of the uniaxial tensile test system are as follows: (1) The system can realize the stress feedback, except carry out the traditional displacement control and stress control of the load alone, also stress-strain linear combination of servo control. (2) The measurement system and control system are realized by hardware rather than computer software; the structure is simple and compact; the reaction time of the system action is short; the performance is stable and reliable; the space of upgrading is large. (3) The control and monitoring data use simulate signal transmission and the test process control and data acquisition accuracy are higher. (4) By using high strength adhesive, the specimen is in the state of tension; and the stress state of rock mass can be simulated in real engineering. Using this system, the generalized relaxation test of tage tuff under tensile stress has been accomplished, and the test results show that the device has good practicability and reliability, so as to provide a new method and means for studying the mechanical properties of generalized stress relaxation under the action of tensile stress of rock in engineering practice.