Need help with a laminate analysis problem

Click For Summary
SUMMARY

The discussion focuses on a laminate analysis problem involving a flat laminate composed of 9 plies of unidirectional carbon fibre reinforced plastic with a specific stacking sequence of 0/60/0/-60/90/-60/0/60/0. The ply properties include E1 = 134 GPa, E2 = 10.3 GPa, G12 = 5.1 GPa, and v12 = 0.326. The user seeks to calculate the load per unit width (Nx) at which each set of plies will fail, but lacks stress or strain values to apply the Tsai-Hill failure criteria. Guidance is requested on progressing from calculated Q, Qbar, and A, B, and D matrices towards determining ultimate strength while considering early ply failures.

PREREQUISITES
  • Understanding of laminate theory and mechanics of composite materials
  • Familiarity with the Tsai-Hill failure criteria for composite materials
  • Knowledge of matrix calculations for A, B, D matrices in laminate analysis
  • Experience with boundary conditions in plate bending problems
NEXT STEPS
  • Research methods for calculating stress and strain values in composite laminates
  • Study the application of the Tsai-Hill failure criteria in detail
  • Explore advanced laminate analysis techniques, including finite element analysis (FEA)
  • Learn about boundary condition matching in multi-layered plate bending problems
USEFUL FOR

This discussion is beneficial for composite material engineers, structural analysts, and researchers involved in laminate design and failure analysis, particularly those working with carbon fibre reinforced plastics.

unique098
Messages
1
Reaction score
0
Thread moved from the technical PF forums so no Homework Help Template is shown
Hi, I am looking for some guidance on a problem I am trying to solve on laminate analysis.
This is a flat laminate (9 plies with a thickness of 0.125mm) of unidirectional carbon fibre reinforced plastic with a stacking sequence of:
0/60/0/-60/90/-60/0/60/0.

Ply properties are as follows:

E1 = 134 GPa, E2 = 10.3 GPa, G12 = 5.1 GPa and v12 = 0.326

stress1UT = 2090 MPa, stress2UT = 97 MPa, stress1UC = -1600 MPa, stress2UC = -356 MPa and

T1UT = 114 MPa

How do I calculate Nx, the load per unit width in the 0 angle direction at which each set of plies will fail. I do not have any stress or strain values so I am unable to put this into the Tsai-Hill formulae. Is there any way I can calculate the stress and strain values? So far I have calculates the Q, Qbar and A B and D matrices. I do not know how to go further from this.
In addition to this, I need to find ultimate strength allowing for those plies which fail early.

I am not looking for plain answers, I would prefer some guidance on how to go about solving this. Any help is appreciated.
 
Physics news on Phys.org
Can you consider this as a plate bending problem, with a stack of plates? It would seem that each plate should bend according to the usual elastic bending model. Then you would need to require that the displacements on the top face of one plate should match those of the underside of the plate above. Then it is a matter of matching such boundary conditions through the whole stack, a bit messy, but possible in principle.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 15 ·
Replies
15
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
3
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K