private formula
for k_1 see https://www.engineersedge.com/material_science/_rectangular_plate_circular_load_13646.htm
| ym | maximum deflection (m) |
| k1 | value dependent on geometry (dimensionless) |
| P | concentrated load (N) |
| a | width palte (m) |
| E | Young's Modulus, 210GPa for steel (N/m2) |
| t | plate thickness (m) |