Development Of A Coilable Space Mast And Study On Mechanical Properties Of Shape Memory Materials

Intelligent Materials and Structures is a new comprehensive science,it is one of the international advanced subjects and gets more and more attentions.Shape memory material is one of the main components of intelligent composites.It has shape memory effect and can be used as a new space material for deployable space structures.This thesis discuss on shape memory materials,characterized shape memory polymer and shape memory alloy fundamental mechanical properties,focuses on the dynamic mechanical properties of 4-harness stain carbon fiber weave reinforced composites.On this basis,a shape memory actuator was designed,fabricated,a preliminary performance was demonstrated.Otherwise,on the basis of particular space probe mission requirement,designed a new high precession coilable space mast and analysed the influencing factors of modal.First of all,uniaxial tensile tests under constant temperature and the dynamical mechanical analysis tests of shape memory polymer were carried out respectively.The storage modulus-temperature and the tangent of loss angle-temperature curves were obtained.The author was used VIC-2D digital speckle technique in uniaxial tensile process for obtaining the displacement field and strain field.Based on the displacement field,calculated the shear modulus and the Poisson ratio of shape memory polymer.Secondly,three different kinds of 4-harness satin carbon fiber weave reinforced composites were carried out the dynamical mechanical analysis test respectively.The experimental results indicate that 4-harness satin carbon fiber weave reinforced composites have good memory capacity.The SMP involved with carbon fiber weave reinforced composites will lead to T_g and tan?reduced,but E is significantly enlarged.T_g and tan?of the same 4-harness satin carbon fiber weave reinforced composites are almost in common,but E differ greatly in its warp direction and weft direction.The author compared the value of T_g,which was calculated by the maximum value through the curve of tan?and E_l.Thirdly,differential scanning calorimetry test and uniaxial cyclic tensile test of shape memory alloy were carried out respectively.The author designed an intelligent composites actuator,which based on shape memory alloy's effect.The author carried on the preliminary test and analysis to the test existence problems.Finally,on the basis of particular space probe mission requirement,proposed a three-staged sequence extending coilable mast and illustrated the relationship and the function of each part.The author analysed the influence factors of modal,included the size of stiffening cables,the pre-stress of stiffening cable and cross section of horizontal and vertical bars.The modal test of the assembled coilable mast is carried out,and measured the modal and natural frequencies of the three kinds of excitation modes.The presented work is valuable to the engineering designing.