Cantilever Beam Subjected to a Concentrated Shear Force

Objective: Determination of the strain state of a cantilever beam subjected a concentrated shear force.

Initial data files:

CS06_c_v11_3.spr bar model
CS06_p_v11_3.spr plane-stress model

 

Problem formulation: The cantilever beam of a rectangular cross-section is subjected to a concentrated shear force Р applied at its free end. Determine the displacement z of the free end of the beam taking into account the effect of the transverse shear.

 

Initial data:

E = 3.0·107 Pa - elastic modulus,
ν = 0.0 - Poisson’s ratio,
L = 10.0 m - beam length;
t = 0.1 m - width of the beam cross-section;
h = 1.0 m - height of the beam cross-section;
k = 1.2 - shear coefficient;
P = 1.0 N - value of the concentrated force

 

Finite element model: Two design models are considered:

 

Bar model (B), design model – plane frame, 10 elements of type 10. The spacing of the finite element mesh along the longitudinal axis is 1.0 m. Boundary conditions at the clamped end are provided by imposing constraints in the directions of the degrees of freedom: X, Z, UY. Number of nodes in the design model – 11.

Plane-stress model (P), 10 eight-node elements of type 30. The spacing of the finite element mesh along the longitudinal axis is 1.0 m. Boundary conditions at the clamped end are provided by imposing constraints in the directions of the degrees of freedom: X, Z. Number of nodes in the design model – 53.

Results in SCAD


Design model. Bar model


Deformed model. Bar model


Displacements z (m). Bar model


Design model. Plane-stress model


Deformed model. Plane-stress model


Displacements z (m). Plane-stress model

 

Comparison of solutions:

Model

Displacements z, m

Deviations, %

Bar (B)

-1.341∙10-3

0.00

Plane-stress (P)

-1.340∙10-3

0.07

Theory

-1.341∙10-3

 

Notes: In the analytical solution, the displacement z of the free end of the beam taking into account the effect of the transverse shear is determined according to the following formula:

\[ z=\frac{4\cdot P\cdot L^{3}}{E\cdot t\cdot h^{3}}\cdot \left( {1+\frac{k\cdot \left( {1+\nu } \right)\cdot h^{2}}{2\cdot L^{2}}} \right). \].