I need to calculate whether a polycarbonate sheet can withstand a certain maximum force. The force is an impact force on any one point of the sheet at any given time. All I have are the Young's modulus and the dimensions of the sheet. Any ideas how I can go about calculating the maximum force the sheet can withstand? This polycarbonate plate is placed vertically and held on all edges by a frame.


  • $\begingroup$ is that force gently applied over time? is it an impact force? is the force equally distributed over the surface or is it a point load? $\endgroup$
    – Solar Mike
    Apr 8, 2020 at 13:56
  • $\begingroup$ Thanks for the response! I have edited the question now to reflect your questions $\endgroup$
    – Hal
    Apr 8, 2020 at 14:21

1 Answer 1


For impact force calculations you need some more information such as the shear modules and the material properties like toughness and tensile yield and shear yield.

Also you need to define a physical object that will impact the sheet.

If the object is much more rigid than the sheet and pointed it will go through like a bullet.

Imagine an impact force has caused your sheet to behave like trampoline table.

You will see a cone shape deflection under the load opening up to a wide sloped flange depression.

On the very sharp bottom of this cone most of the stress is tensile due to cylindrical elongation of this segment. And some crushing at the center.

But as we move up most of deformation is due to punching shear on concentrically widening rings with a bit of biaxial bending moment.

The military shield and armoire manufacturers have done extensive research on the competition between the pentration of mortar and resistance of shields.

If you are limiting your limit to elastic range, your force has to have a nominal minimum diameter and you can assume an arbitrary dynamic factor of 3 and check Roark's handbook of engineering formulas for some static forces and edge support conditions.


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