How to input seismic waves in different directions?
Moderators: silvia, selimgunay, Moderators
How to input seismic waves in different directions?
In OpenSees, input seismic waves for a 3D structure in different directions are simplified like this: in X axis, the angle between X is 15。, or the angle between Y is 30。. In OpenSees Manual, only input directions that are relevant to X and Y axis is presented, however, no such conditions about changing direction input of seismic waves are mentioned. Therefore, how to solve this problem?
rotate the model or transform the forces
1.I've considered the rotation the model you said while this will bring some problems in relevant,such as,the transformation from the local coordinate to the global coordinate of the element and after the rotating of the model, how to get the computational analysis of beam-element and column-element come true? Can you explain it in detail ?
2.Can we do it like this for the transform the forces? As to the input motions, you can decompose the input motion to x-and y- directions (accel x sin(alpha) and accel x cos(alpha)) and then input these components in x- and y- direction simultaneously. If we can do it in such way,so does it have the equivalent effection to the structure with the input of undecomposed single changing directions? Can you prove it in theory?
2.Can we do it like this for the transform the forces? As to the input motions, you can decompose the input motion to x-and y- directions (accel x sin(alpha) and accel x cos(alpha)) and then input these components in x- and y- direction simultaneously. If we can do it in such way,so does it have the equivalent effection to the structure with the input of undecomposed single changing directions? Can you prove it in theory?