Hi everyone. I do need to replace a thick steel plate with a composites (Kevlar+Carbon) plate. I do not have the strength of the composite material, so how I could know the strenght of the composite (without testing) to get the equivalent thickness

Thanks in advance!

This is much more difficult, compared to the metal part. The strength of a composite part varies with the fibre content and orientation, as well as with the used fibres (there are different types of carbon and kevlar). Additionally you have to think about the fastening points, wich can easily become the weak point. So even a simple plate can be quite difficult to calculate.