Shaking Table Test On The Seismic Response Of Spatial Structure Based On The Control Of SMA

Shape Memory Alloys is a kind of new functional materials with various properties, which has a unique shape memory effect. Namely, when martensitic SMA produces plastic deformation at low temperature, the deformation can completely disappear and restore to its initial state at high temperature. If the deformation recovery of SMA is constrained, it will generate a large restoring force. And SMA materials also have good pseudo elasticity and high damping characteristics, which can dissipate a large external energy and can reduce the seismic response of structures.In this article, according to the stress and deformation characteristics of spatial structure under the action of the earthquake, based on the unique super-elastic, shape memory effect and other characteristics of SMA, both SMA passive and hybrid active-passive control system were developed, will be integrated in the spatial structure of the model for the corresponding shaking table test and analyze. The specific work and research content are as follows:(1) Using computer servo control system material testing machine, mechanical performance tests were made on 12 groups of 48 austenitic and 3 groups of 30 martensitic shape memory alloys. By changing the current, loading amplitude, loading rate, cyclic numbers, and diameter the main test parameters of shape memory alloy, to study the mechanical characteristic of SMA. The test results showed that: the loading amplitude and loading rate are the important parameter affecting the mechanical characteristics of austenite phase SMA, current and loading amplitude are the important factors affecting the restoring force characteristics of martensitic phase SMA.(2) Briefly introduced several types of constitutive relation models of SMA and their advantages and disadvantages, and introduced super-elasticity restoring force model of SMA adopted in the ANSYS program. At the same time, based on the shape memory alloy material tests and Brinson constitutive model, deduced a martensitic phase SMA one-dimensional force formula and established a simplified model of piecewise linear restoring force.(3) In order to verify the effectiveness of SMA passive and hybrid active-passive control system, in this paper designed and made one of two span three story spatial structure model and developed two new type of shape memory alloy wire material control device and electric heating/voltage regulation system and integrated in the spatial structure model. Choose EL-Centro and other three kinds of seismic waves and three different acceleration peak values, the use of passive and hybrid active-passive control method, are not installed, installation, installation of stochastic optimization of shape memory alloy control system under 30 different conditions of spatial structure model shaking table test. The experiment showed that: under normal circumstance, using passive control system, seismic acceleration response of model structure can be reduced about 20% and the interlayer displacement can be reduced about 30%; while using hybrid active-passive control system, seismic acceleration response of the model structure can be reduced about 30% and the interlayer displacement can be reduced about 45%. Those show that the proposed control method is good and has the good application value and prospect.