TORSION IN SOLID RECTANGULAR SECTIONS
Torsional stiffness constant, shear stress and angle of
twist parameters of a solid rectangular section, which is under twisting moment, can be calculated with the following calculator. The calculator is only
valid for solid rectangular sections. The formulas used for calculations are given in the "List of
Equations" section.
Calculator:
Note: Use dot "." as decimal separator.
RESULTS 
Parameter 
Symbol 
Value 
Unit 
Maximum shear stress* 
τ_{max} 



Angle of twist 
_{θ} 



Torsional stiffness constant 
K 



Note: *Maximum shear stress is at the midpoint of each longer side for a≥b.
Definitions:
Angle of Twist: The angle through which a part of an object such as a shaft is rotated from its normal position when a torque is applied.
Modulus of rigidity (modulus of elasticity in shear): The rate of change of unit shear stress with respect to unit shear strain for the condition of pure shear within the proportional limit. Typical values Aluminum 6061T6: 24 GPa, Structural Steel: 79.3 GPa.
List of Equations:
Step 
Parameter/Condition 
Symbol 
Equation 
1 
Angle of twist 
θ 

2 
Maximum shear stress 
τ_{max} 

3 
Torsional stiffness constant 
K 

Symbol 
Parameter 
T 
Twisting moment 
K 
Torsional stiffness constant 
2a 
Longer edge
length 
2b 
Shorter edge
length 
L 
Length of the beam 
G 
Modulus of rigidity 