The Research Of Positive/Negative Stiffness Conversion Structure Based On Shape Memory Polymers

Shape memory polymer structure is a recent research focus, which, undercertain excitation conditions (such as: thermal, electrical, magnetic, optical) canproduce very large reversible deformation, it has a structure carrying capacity, alsohas an active deformation function. With the development of science and technology,in many ways, we need to control or prevent the occurrence of an object in motionvibration, etc. The study found negative stiffness structural design applicationsisolator has good isolation performance. Negative structural stiffness characteristicsof traditional materials design is not controllable, to carry out the master controlnegative stiffness structural stiffness characteristics of great significance in theactive control of vibration isolation performance of the structure.Firstly, according to the basis of the size of the disc springs under certainconditions with negative stiffness characteristics on the performance ofepoxy-based shape memory polymers and shape memory properties of largedeformation recovery designed a positive/negative stiffness conversion discstructure. Viscoelastic shell theory based on theoretical analysis and thermodynamicproperties of negative stiffness properties and structure of the negative stiffness ofthe structure, to achieve a positive and negative stiffness structural transformation.Secondly, this paper ABAQUS finite element software negative stiffness ofepoxy shape memory polymer structures were verified negative stiffnesscharacteristic analysis, the load of negative stiffness of the structure-deformationcurve; Analysis of the negative stiffness of the structure in the free state of thenatural frequencies and mode shapes.Finally, based on theoretical analysis and ABAQUS finite element simulation,the design of the mold of negative stiffness of the structure, and use its epoxy shapememory polymer positive/negative stiffness of the structure has been developed.On the development of the negative stiffness of epoxy shape memory polymerstructure, completed the static test, the thermodynamic performance testing andvibration testing. Among them, the static tests proved negative stiffnesscharacteristics of the structure; Thermodynamic performance test results show thestructure of different temperatures under load conditions-the relationship betweendeformation and shape memory properties; Vibration test analyzes the structure ofdifferent heights in the free state of natural frequencies and modal damping ratio.Research results provide epoxy-based shape memory polymer positive/activecontrol of structural rigidity to convert the low-frequency vibration isolation in terms of negative reference.