158x
008852
2024-01-15

VE0052 | Cantilever with Moment Loading at Free End

Description

A cantilever is loaded by the moment M at its free end. Using the geometrically linear analysis and the large deformation analysis and neglecting beam's self-weight, determine the maximum deflections ux and uz at the free end. The verification example is based on the example introduced by Gensichen and Lumpe (see the reference).

Material Steel Modulus of Elasticity E 210000.000 MPa
Shear Modulus G 81000.000 MPa
Geometry Tube Cantilever Length L 4.000 m
Diameter d 42.400 mm
Wall Thickness t 4.000 mm
Load Bending Moment M 3.400 kNm

Analytical Solution

Geometrically Linear Analysis

Considering the geometrically linear analysis, the problem can be solved according to the Euler-Bernoulli equation. For the given geometry, loading and boundary conditions, the result maximum deflection uz,max is following:

The deflection ux,max considering geometrically linear analysis is zero.

Large Deformational Analysis

A beam in the large deformation analysis is described by the nonlinear differential equation and it is illustraded in the following figure.

The term on the right-hand side is constant and consequently the left-hand side, which is directly the beam curvature κ, is also constant. The only curve which has constant curvature is a circle, therefore, the solution to this problem is a circle arc of radius R.

R is the radius of the circular arc. The angle of the circular arc α equals to α=L/R.

RFEM and RSTAB Settings

  • Modeled in RFEM 5.05, RSTAB 8.05 and RFEM 6.01, RSTAB 9.01
  • The element size is lFE= 0.400 m
  • The number of increments is 5
  • Isotropic linear elastic material model is used
  • Shear stiffness of members is activated
  • Member division for large deformation or post-critical analysis is activated

Results

ux, max [m] Analytical Solution RFEM 6 Ratio RSTAB 9 Ratio
Geometrically Linear Analysis 0.000 0.000 - 0.000 -
Large Deformation Analysis -0.337 -0.336 0.997 -0.336 0.997
uz, max [m] Analytical Solution RFEM 6 Ratio RSTAB 9 Ratio
Geometrically Linear Analysis 1.441 1.441 1.000 1.441 1.000
Large Deformation Analysis 1.379 1.380 1.001 1.380 1.001
ux, max [m] Analytical Solution RFEM 5 Ratio RSTAB 8 Ratio
Geometrically Linear Analysis 0.000 0.000 - 0.000 -
Large Deformation Analysis -0.337 -0.338 1.003 -0.337 1.000
uz, max [m] Analytical Solution RFEM 5 Ratio RSTAB 8 Ratio
Geometrically Linear Analysis 1.441 1.441 1.000 1.441 1.000
Large Deformation Analysis 1.379 1.380 1.001 1.380 1.001

References
  1. LUMPE, G. and GENSITEN, V. Evaluation of Linear and Nonlinear Member Analysis in Theory and Software: Test examples, causes of failure, detailed theory. Ernest.