CVEN2303代写、代写Matlab程序语言

日期：2022-07-25 08:47

Lab assignment – CVEN2303

Submission due by 2pm 5th of August

You need to show and submit all your working solution either handwritten or typed.

You can use Matlab (or other software) to invert the structural matrix or for your entire

solution procedure. You need to upload a copy of your code or Excel sheet if used.

If you are using Matlab, it is expected that you add some titles/subtitles and comments to

the different sections of your code.

It is expected to add one or two pages of handwritten or typed Flowchart of your coding

or solution procedure, that will simply reflect the various stages taken in your code.

For part 1.3, it will be good to include differences between the theoretical and measured

results in percentages. That will prepare you to discuss the differences between the

results.

Introduction

In this assignment students are expected to calculate axial forces of a Warren truss and a

basic Roof truss using the stiffness method, and then to compare with experimental results.

The test videos can be watched on moodle (might take a while to upload). A guide for using

Matlab (optional) is also available on moodle.

Warren Truss

The Warren truss under investigation is illustrated in Figure 1, which consists of eleven

300mm long truss members that create 5 equilateral triangles as shown. The distance between

the supports is 900mm.

Figure 1: Warren Truss

2

The truss is simply supported with a pin support located on the left, and a roller support

located on the right. For consistency, use the members numbering as shown in Figure 2.

Figure 2: Reference system for Warren truss structure

The pin support is located at Position L0; the roller support is located at Position L3; the

vertically downwards load F is applied at Position L2.

Basic Roof Truss

The basic roof truss under investigation is illustrated in Figure 3, which also consists of

eleven truss members as shown. The length of members 2, 6 and 10 shown below is 300mm.

The distance between the supports is 900mm. The height of the truss measured from the

centre of the supports to the Position U1 (Refer to Figure 4) is 259.8 mm (150√3 mm).

Figure 3: Basic Roof Truss

3

Figure 4: Reference system for roof truss structure

The truss is simply supported with a pin support located on the left, and a roller support

located on the right. For consistency, use the members numbering as shown in Figure 4.

Assume that member 3 is perpendicular to members 1 and 4 and that member 9 is

perpendicular to members 8 and 11. The pin support is located at Position L0; the roller

support is located at Position L3; the vertically downwards load F is applied at Position L2.

Part 1.1 (70%): Calculate theoretical axial forces of the Warren and Roof trusses

Use the stiffness method to calculate the axial forces of all members in the Warren truss and

the Roof truss under a load that is applied at Position L2 with a magnitude of 300 N

downwards. You may use any computer software to do the calculation.

The material of the truss member is acrylic, and its elastic modulus is E = 2500 N/mm2. The

cross-section area of each truss member is A = 250 mm2.

Part 1.2 (10%): Determine experimental axial forces of the Warren and Roof trusses

From the measured strains, the experimental member axial forces can be obtained using:

N = EA??

where E is the elastic modulus of the material, A is the cross-section area, and ? is the

measured strain which is multiplied by 106. Therefore, in order to get the actual value of

you need to multiply the measured value by 10-6.

Part 1.3 (20%): Results discussion

Compare between the theoretical and experimental results and discuss four possible reasons

for any discrepancies between the results.