Is there a way to improve the calculation efficiency in this case?

Hi, everyone,

I am trying to use Duhamel Integral to calculate a continuous bar axial vibration response,

Below is my process:

I only used the eta1(t) part and the first phi*eta1(t) (add from i=0 to 0)

But it takes 5mins for Mathcad to finish the calculation of this simple case. 

Is there a way to improve the calculation efficiency?

Before this, I also tried to create a matrix with 100 points for u1, and plot the matrix,

but the time for the final calculation is also very long.

Given this is only a simple case, adding from 0 to 0, I am afraid that it takes forever to finish the accumulation of more phi*eta.

I propose that the problem of this low efficiency is with the Duhamel integral,

Is there a way to improve it?

Thank you very much!

Best Regard

Shawn