Related Resources: material science

Two Block Shear Spring Design Equations and Calculator

Springs of rubber bonded to metal are made in a wide variety of configurations. The rubber is usually in shear and, because of the high internal damping, such springs are used for limiting vibrations.

Two-block shear spring - load P

Symbols used:
A = Area rectangular plate, (mm2, in2)
P = Loading Force, (N, lbs)
E = Young’s modulus, (N/mm2, lbs/in2)
H = Rubber thickness, (mm, in)
G = Shear modulus

Two-block shear spring

Stress equation

Shear stress τ = P / 2A
Deflection y = Ph / 2AG
where G = shear modulus.

Modulus and strength of rubber
G = 0.3 to 1.2MPa
E = 0.9 to 3.6 MPa
Allowable shear stress = 0.2 to 0.4 MPa
Deflection limited to 10% to 20% of free height.