Shear Moment Diagram

[vorwald]

Does anyone have suggestions / experience with generating shear moment diagrams for a plate / rod elements. I've applied the external loads and constraints, and now I would like to plot shear / moment of an internal part.

 

[corus]

Shear forces and bending moments can't be plotted as contours for plate elements as internal to the structure the resultant at a node is zero. If you do plot them then the contours will only show values at the exterior nodes.
You can plot the shear stresses and the bending stresses though in some programs you have to obtain the bending stresses by obtaining the difference between the top surface and middle surface stresses.
I've seen the values plotted for beam/rod elements in most programs which presumably plot the element nodal values.

 

[vorwald]

Using NASTRAN, for a plate structure, the shear force, axial force, and moment are given by
SF = integral of XY_membrane_force
AFy = integral of Y_membrane_force
M = integral of (neutral axis-z)*Y_membrane_force

The neutral axis location can be estimated from the location of maximum xy shear

I used FEMAP to output the centroid of each element, and the corresponding element membrane forces/shears. I used MATLAB to locate the elements at a station, and intergrated using trapazoid command to get the desired forces/moments. Plotted the results verses station to be similar to a beam diagram.

I think the results can also be obtained from integrating the corresponding stresses multiplied by plate thickness.