# Daniel Tan

Topics: Second moment of area, Torque, Experiment Pages: 6 (1387 words) Published: April 25, 2013
Table Of Content

Abstract3

1.0 Introduction3

2.0 Experiment Design4
2.1 Materials4
2.2 Procedure4

3.0 Results and Calculations5
3.1 Tables5
3.2 Graphs7-9
3.3 Discussion9

4.0 Conclusion and Recommendations10

Abstract
This experiment is conducted to measure the transverse bending deflection of the tie bar and at the same time comparing it to the theoretical values. The two theoretical formulae to get the central deflection in this experiment are simple theory method and exact formula. By comparing these formulas to the experimental formula, the most suitable method to measure the central of deflection could be obtained. This experiment is then continued by measuring the adequateness of the Simple Theory by allowing a 10% error. In overall, the experimental value is one of the best method to find the central deflection of the tie bar.

1.0 Introduction
The structure and the design of a mechanism sometimes counteract the line of pull by having a tension force. This means that the tension member has to carry a both tension and bending with an increase eccentricity of the load at the back. In the experiment, the load line is outside the middle third of a square tie bar. This causes the bending moment takes over and there will be a bending deflection. A mathematical solution can be found from the eccentric loaded tie by using some differential equations. In this experiment, the students to have the opportunity to study on how to measure the transverse bending deflection of the tie bar and comparing it with the theoretical values. There are two theoretical values that are used to get the central deflection of the tie bar which are the simplified formulae and the exact formulae. One of the approximate solutions that could be obtained is by regarding the tie bar as a beam with equal and opposite couples applied which then produces circular bending. A demonstration of eccentric tie is being made so that a visual valuation is visible and the bending can be seen clearly. Not only that, this also enhances the students to check the order of the accuracy that can be achieved by using simple theory. With this experiment, students are able to measure the transverse bending deflection of the tie bar and comparing it with the theoretical values.

2.0 Experiment Design

Figure 1: Eccentric Tie Apparatus
2.1 Materials
The apparatus used in this experiment are eccentric tie apparatus, load hanger 5N and weight sets which consist of 50N, 20N, 10N and 5N.
2.2 Procedure
1. The apparatus was set up with the greatest eccentricity of loading which is 75mm. The zero load reading of the dial gauge is being set with the load hanger in position.
2. An increment of 10N is being put onto the load hanger up to 90N and the reading of the central deflection for each increment is recorded into the results and being tabulated in the first table.

3. The procedure is being repeated with the load at 55mm eccentricity and 35 mm eccentricity, adding 120N in increments of 20N and adding 140N increments of 20N respectively.
4. Both of the results are tabulated in the second table and third table respectively.

3.0 Results and Calculations
3.1 Tables
Table 1 : Deflection of an eccentric tie at 75mm eccentricity of load. Eccentricity of Load (mm)| Applied Load (N)| End Moment (kN.mm)| Gauge Reading (No. of division)| Central Deflection (mm)| 75| 0| 0.00| 0.0| 0.000|

| 10| 0.75| 65.5| 0.655|
| 20| 1.50| 173.0| 1.730|
| 30| 2.25| 280.0| 2.800|
| 40| 3.00| 380.0| 3.800|
| 50| 3.75| 493.0| 4.930|
| 60| 4.50| 598.0| 5.980|
| 70| 5.25| 695.0| 6.950|
| 80| 6.00| 803.0| 8.030|
| 90| 6.75| 832.0| 8.320|

Table 2 : Deflection of an eccentric tie at 55mm eccentricity of load. Eccentricity of Load (mm)| Applied Load (N)| End Moment...