Can anyone help me how to update the modulus of elasticity over time using subroutine in Abaqus. In my case, I want to model the time-dependent elastic modulus for several time cases and get the displacement result for each time case. My model is a simply-supported 2D prestressed concrete beam with a single straight tendon. Let's say the time cases are from loading day (28 days) until 365 days after casting the concrete. And I want to get the upward displacement due to prestress load only for each time case or each updated elastic modulus. I tried to use USDFLD subroutine but because I'm newbie either to subroutine or Fortan, my job got aborted. I'm sure I did some mistakes in the codes.

[Updated Question]

So, I have tried this method by defining the field for each elastic modulus that I want. Then I define the time using amplitude (28-365 amplitude mean days). And I assign the field as a predefined field in step analysis with magnitude 1 and assign the defined amplitude. But when I submitted the job, I got this warning message saying that I should define the predefined field in the initial step instead, but if I did it, I couldn't assign the defined amplitude, so how do I define the time? And even if I define the field in the initial step, I will just get the displacement result for the latest defined elastic modulus (field 8), where I want to get displacement result for each elastic modulus.

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