i want to model a spherical tensegrity and analyze it under diffrent mechanical condition. now i modeled a 6-strut tensegrity define material to solve it but cant define prestress in cable and strut? please help me how can i do this?
Look up *PRE-TENSION SECTION in the keyword documentation. I've used if for preloading cables, rods, bolts, and other structures before. Another method is to use *TEMPERATURE to impose a strain on the component, but with tensegrity there's a tricky optimization problem to get all the tensions right.
model the cable as link member and stress it by cooling as follows:
cooling temp. = stress / ( coeff. of expansion * elastic modulus )
usually cooling temp. is about 500 oC
As I mentioned above, you can use temperature to impose your prestress, but the formula above only works assuming the ends of the cable are rigidly anchored. If they are connected to other deformable members then the temperature you impose to reach your target prestress is a function of those stiffnesses. Solving for the tensions required quickly becomes unmanageable. I recommend *PRE-TENSION SECTION or including a connector element in the cable and using *CONNECTOR ACTUATION to directly input the tension you want.
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