Need help with a laminate analysis problem

• unique098
In summary, the conversation discusses a problem involving laminate analysis of a flat, unidirectional carbon fibre reinforced plastic with a specific stacking sequence and ply properties. The goal is to calculate the load per unit width and ultimate strength, taking into account early ply failure. The speaker is seeking guidance and suggestions for solving this problem, potentially by considering it as a plate bending problem and matching boundary conditions throughout the stack.
unique098
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.

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.

1. What is a laminate analysis problem?

A laminate analysis problem is a type of engineering problem that involves analyzing the behavior and properties of a layered composite material, also known as a laminate. This can include determining the stress and strain distribution, stiffness, and failure modes of the laminate under various loading conditions.

2. How is a laminate analysis problem solved?

A laminate analysis problem is typically solved using analytical methods or numerical techniques such as finite element analysis. These methods involve breaking down the laminate into smaller, simpler elements and using mathematical equations to calculate the behavior of each element. The results are then combined to determine the overall behavior of the laminate.

3. What types of materials are commonly used in laminate analysis?

Laminate analysis can be applied to a wide range of materials, including composites such as carbon fiber, fiberglass, and Kevlar, as well as natural materials like wood and bamboo. The properties of these materials can vary greatly, so it is important to carefully select the appropriate material properties for accurate analysis.

4. What are the common applications of laminate analysis?

Laminate analysis is commonly used in the aerospace, automotive, and marine industries, as well as in the design of sports equipment and consumer products. It is also used in the manufacturing process to optimize the design and production of laminated structures.

5. What are some challenges in solving a laminate analysis problem?

One of the main challenges in solving a laminate analysis problem is accurately modeling the complex behavior of the material layers and their interactions with each other. This requires a thorough understanding of material properties and behavior, as well as advanced analysis techniques. Additionally, the manufacturing process can introduce variability in the material properties, making it difficult to predict the exact behavior of the laminate.

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