Material Mechanics Experiment
Bending Stress in a Beam
JINGBO YU (J9089826 )
School of Science and Engineering
Date: 2/4/2010
Introduction and Aim
In engineering mechanics, bending stress is the normal stress that is induced at a point in a body subjected to loads that cause it to bend. And it always loaded on beams or shafts. Beams and shafts are important structural and mechanical elements in engineering. So that, learn how to determine and calculate the stress in theses members caused by bending is important.
At this experiment, the equipment showed as below is required. It consists of an inverted aluminum T-beam, and some strain gauges is fixed on it. While the
Stretch or compress is happen on the beam, the strain gauges can experience this change in electrical resistance. There are two positions on the top of the beam is loaded by the panel assembly and load cell. If we compare this load method with one position load, there are two main advantages is appear. The first one is allows a gauge to be placed on the top of beam, and the other one is the constant bending moment area it creates gives better strain gauge performance and avoids stress concentration close to the gauge positions.
From these sensors the stain on the beam can be measured, and for more accurate data, there are more gauges on the beam, they called dummy gauge. They are used to reduce inaccurate reading caused by temperature changes and thermal expansion.
In addition, there are is a digital strain display, it used to converts the change in electrical resistance of the strain gauges to show it as displacement. We can read the load on the beam from that small displayer immediately.
[pic]
Shown with the Digital Force Display and fitted to a Structures Test Frame (both supplied separately)
Experimental Setting
Before start this experiment, there are some preparations need to do.
1. Check all parts of equipment include electrical leads.
2. Check electrical...