FEA Simulation for ASTM C393

ASTM C393_Standard Test Method for Shear Strength

*work in progress*

Intro

This page will show the simulation results for a 3-point bend test on 75 x 200 mm sandwich construction with various core thicknesses. The purpose of this test is to obtain the compressive strength and from that compressive strength, calculate shear strength. We will use the results from this simulation to compare with our in-person results to see if they conform to our standards.

 

Stackup:

The test specimen I used was a sandwich of a top layer using 3 layers of 0.15 mm prepreg, a 1 inch, 1/2 inch, or 1/4 inch Nomex and a bottom layer again using 3 layers of 0.15mm prepreg.

Figure 1: Picture of the test specimen with fibre directions

The loading condition:

For this simulation, I used a nodal force of 1000 N downwards on the top face. There are also fixed supports on both ends of the specimen, on the bottom face.

 

 

Figure 2: Loading and Boundary Conditions

 

 

Figure 3: Deformation of sandwich construction (1/4 inch core)

 

 

Results:

Specimen

Maximum Deformation (mm)

Specimen

Maximum Deformation (mm)

1/4 Inch Nomex

1.2

1/2 Inch Nomex

0.58726

1 Inch Nomex

0.27903

 

1/4 Inch Nomex

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Top Layer

-79.27

67.87

Averaged value

Honeycomb

-0.0015432

0.0014185

 

Bottom Layer

-64.94

76.18

Averaged value

 

1/2 Inch Nomex

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Top Layer

-40.422

34.893

Averaged value

Honeycomb

-0.00082218

0.00076126

 

Bottom Layer

-34.106

39.51

Averaged value

I Inch Nomex

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Sandwich Layer

Minimum Stress (MPa)

Maximum Stress (MPa)

Notes

Top Layer

-20.348

17.697

Averaged value

Honeycomb

-0.0004234

0.00039471

 

Bottom Layer

-17.492

20.113

Averaged value

 

Below is a table of where the stresses occurred in the 1/4 inch Nomex

 

Layer

Stress

Layer

Stress

Top

 

 

Comment: Max stress of 64.94 MPa on red area.

Middle

Comment: Max stress of 0.0014185 on red area.

Bottom

Comment: max stress of 72.423 MPa on red area.