# ENGT5152 Composite Materials

To develop the skills in continuous fibre reinforced laminates design for structural applications. ENGT5152 Composite Materials

Objectives:

(1)Learn how to deal with angle lamina in structural analysis

(2)Familiarise with the steps and procedures in macromechanical analysis of laminates.

(4)Awareness of the social, ethical and environmental impacts of using composite materials.

### The Design Problem

A 2 m long cylindrical pressure vessel (Figure 1) with an inner diameter of 0.8 m is subjected to an internal gauge pressure of 2.0 MPa. The vessel operates at room temperature. High strength steel with a yield strength of 800 MPa was initially used in the design to make the vessel. The required safety factor is 2.0. It is

(1)Conduct stress analysis of the pressure vessel to determine the relationship between stress, pressure, vessel dimension and vessel wall thickness.

(2)Find applied loads in x and y directions, Nx and Ny, in N/m.

(3)Design the stacking of the lamina layers, considering orientation and number of layers.

(4)Using the Programme “Laminate” to find out global and local stresses and the safety factor (SF) for each layer.

(5)If SF is smaller than 2 in one or more layers, then increase the number of layers or change orientations (must be symmetric), and conduct the analysis again. You may need several attempts before achieving a SF larger and close to 2 in every layer.

(6)If SF is much larger than 2 in all layers, then reduce the number of layers or change orientations (must be symmetric), and conduct the analysis again. You may need several attempts before achieving a SF larger and close to 2 in every layer.

(7)If SF is larger but close to 2 in every layer, then the design is valid.

(8)Try other stacking/orientation combinations, repeat steps (3) to (6).

(9)Determine the design which requires the minimum number of layers.

(10)Use the optimum design, calculate the volume, weight and relative cost of the composite to be used.

(11)Compare the values in (10) for the composite to those for steel, and comment on weight saving, cost, health and safety issues, and recycling and environmental impact of using composites in this application.

(12)Write your report in a standard format and submit by the deadline specified on the Blackboard.

### Report

Your report should contain (but not limit to) the following:

1.Introduction ….. Introducing background of pressure vessels, their traditional design, material and manufacturing, and aim and objectives of this assignment.

2.Force and stress analysis to determine acting forces in N/m.

3.Procedures in macro-mechanical analysis of laminates.

4.Laminate design

(a)Your strategy in design of the laminate for the pressure vessel.

(b)Your stacking combinations, results from “Laminate” and iterations involved for each stacking.

(d)Calculation of volume, weight, cost ……

(e)Design with steel as the material, calculation of volume, weight, cost ….

### 5.Discussion

(a)Weight saving

(b)Cost comparison

(c)Thickness and volume comparison

(d)Manufacturing route

(e)Potential health and safety issues using composite materials

(f)Recycling and environmental impact

6.Conclusions and recommendations

(a)Draw conclusions from the assignment

(b)Make some recommendations as to how to improve your design in the future, etc. ENGT5152 Composite Materials