Composite engineering(Mechanical engineering)
Assignment Brief ;Design and analysis of a composite structure
SECTION: Design and analysis of a composite seat tube
Initial analysis – Matlab
A client has asked you to analyse an circular tube that will form part of a new range of racing bike frames. They are considering varying tube lengths and diameters as part of their new design: lengths 470 mm to 630 mm and outer surface diameters 25 mm to 44 mm.
They require additional data on the performance of the tube under bending. You may analyse the structure as a clamped-clamped beam subjected to a uniformly distributed load shown in figure 1. The material is Carbon/Epoxy – details given in table 1. Between your group, you need to characterise the performance of a range of top-tube lengths and diameters. You do not need to present detailed results from all analyses (only the failure load and deflection), but you should show a representative analysis of at least one case.
The initial laminate design is “fully-isotropic” laminate composed of 24 plies,
layup := [ − 45,0,+45,90,+45,90,0,90,−45,+45,−45,0, − 45,0,90,0,+45,−45,+45,90,+45,90,−45,0]
Preliminary Analysis – Matlab
Using the effective engineering properties estimate the deflection and failure loads using the Matlab code you have developed. Compare the performance with a benchmark equivalent aluminium tube (i.e. with a wall thickness of 2.64mm).
Finite Element Analysis
The client has asked you to perform a finite element analysis to validate the results. You should perform a 2D shell analysis using ANSYS ACP to assess laminate failure – is your design still satisfactory? What, if any, differences are there between FEA and Matlab, and why do they occur?
Validated FEA analysis.
Summary of key design results.
Clear comparison with baseline and Matlanb
Use ACP to define new material.
Define geometry and oriented surfaces.
Define a fabric and stacking sequence(s).
Import ACP into structural analysis.
Mesh system appropriately.
Define loads and boundary conditions.
Check deformations and stresses.
Use composite failure analysis.
Concise summary of the analysis and key results (what are you
doing).
Any geometric details (Reference surfaces/ orientations etc.)
Loads/restraints, key analysis decisions 2D vs 3D, linear etc.
Meshing and elements used.
Details of convergence and validation steps.
Key results with supporting evidence e.g.
stress/failure/deformations etc.
Concluding summary.
