Learning Forum

[lilly0420]

Hi, I am trying to model strain rate dependent properties of fiber reniorced composite.

I am using Mat 54, LCID to input the strain rate dependent strength in each direction.

 Wonder how the units work. 

From what I've found (the link below), the strain rate seems to be a function of logarism.

      https://dyna-composites.netlify.app/mat_054

Is it different from Mat 162: ln (strain rate/reference strain rate) ?

Is "ln(strain rate)" correct for the x value of the load curve?

 

I am currently modeling composites in solid elements with delamination modeled with contact_tiebreak. 

I don't think my properties with strain rate dependent terms are modeled well, so I wonder if any one has used this option in Mat 54.

Thank you

 

 

[Ram Gopisetti]

Hi , 

unless sepcified its consered as ln(strain rate)

As long as the function used to define LCX includes the rate-dependent variable correctly i.e as follows 

*DEFINE_FUNCTION
21
float comp_strength(float t, float x, float y, float z,
                    float strain_rate)
{
    float sigma0, m;

    sigma0 = 250.0;   // MPa
    m      = 0.05;    // rate sensitivity exponent

    return sigma0 * pow(strain_rate + 1.0, m);
}

cheers ram.