An inertial mass suspended from two or more clamped beams is a structure often used in MEMS accelerometers and other motion sensitive devices. A typical structure is as shown above. Due to the weight of the mass, the structure will have a displacement perpendicular to the surface in the unloaded condition.
Use this form to calculate the displacement of the mass due to its weight and the resulting stress in the beams. This displacement may generate an offset in the output of the sensor and should be considered in the analysis. If there are more springs supporting the mass connected in parallel, the effective spring constant will be the sum of spring constants of all the beams.
The X-Y plot gives the distribution of stress on the beam surface. It shows that the stress changes from positive maximum to negative maximum along the length of the beam. When the mass is pushed down, the surface stress near the clamped edge will be tensile and that near the mass will be compressive. he 2D and 3D surface plots shows the deflection of the beam mass system.