Strain Gauges

Experimental stress analysis is a method of stress and strain testing of materials, to test for behaviour changes of materials under fatigue. The first method of stress analysis used was the Strain Gauge invented by Edward E. Simmons and Arthur C. Ruge created in the late 1930s to test for earthquake stress on elevated water tanks[1]. The creation of lasers and interferometry methods in the 1960s provided the basics of digital image correlation where high-speed cameras could be used to capture behaviour changes in materials during deformation. As the years went on, advancements in imaging, laser and sound technology allowed for new innovative techniques to be used to measure strain and stress. Some of these techniques include are digitised ultrasound images, non-linear least squares and robust stereo-vision system[2].

energy ($\omega$). Solid lines are CRPA cross sections and dashed lines are HF cross sections.

in the xy-plane is equal to the radius (R) of the beam pipe, as shown in Fig.~\ref{beampipeconversion},

The specimen ends were not thick or had moving wedge grips to keep it secure in the holders of the servo-hydraulic load frame. The movement of the specimen in the machine causes some of the data to be an inaccuracy. Also, the transverse strain causes issues with the strain gages that are called transverse sensitivity. The transverse sensitivity affects the accuracy of the data that is being collected for the transverse strain more than the longitudinal strain. This is greatly seen in the percent difference in the strain values such as in one case the Longitudinal strain was .4% while the transverse strain was 30%. Another issue with the strain gages was that if the strain gages weren’t properly placed on the specimen the data accuracy would

Theoretical analysis is one of the most significant phases of the project. The high resistance measurement system developed during this project is primarily based

Each separate truss (of the dimensions 920x5x50mm) consisted of a Pratt truss with nine diagonal members on each side of the centre. The model was tested in sufficiently isolated condition by tutors. It successfully passed the initial weight test, and satisfactorily resisted horizontal forces. Once fitted onto the testing rig, loads were applied and increased incrementally. Slight deformation was observed before failing at 12.5 kg, at which force a collection of members failed in succession, concluding the test.

{N} and {M} are the generalised stresses can can be expressed as membrane strains and curvatures by using the laminar stress-strain relationship and Love Kirchhoff hypothesis.

Set up apparatus as shown in figure 1 above, ensuring the beam is fixed at both ends

2: Place the triple beam balance on a flat suface with your hands (make sure the pointer is pointing at the zero mark. If not, use the adjustment knob to adjust the pointer to zero).

This report aims to describe the experiment performed to investigate the stiffness of a channel section, and in particular calculate the flexural rigidity (EI) of the beam by two different sets of calculations based on the results gained in the experiment. The EI of an object is used

Biaxial tensile testing were conducted by means of EnduraTec ELF 3200 (Bose, Minnesota, USA). This mechanical tester has two vertical axes each of which has a 1 kg load-cell (Model 31, Sensotec Honeywell) and a displacement transducer. The apparatus is equipped with a black-and-white CCD-camera video-extensometer (Watec America LCL 902C camera with Computar TEC55 Lens), allowing the automatic tracking of gauge marks, four dots forming a square plotted on the surface of the specimens.

Prepare the specimen as specified above. Place the specimen in the position clamped it upright in an anvil (vertically) , with a V notch at the level of the top of the clampfacing the striker (Pendulum). Now record the initial height. Remove the pendulum which is allowed to fall freely to strike the specimen with a specified energy. Now use the data points for further calculations.

Hypothesis: If one increases the length of a cantilever, one would expect there to be an increase in deflection/flexion of the cantilever. Similarly, if one increases the mass of the load, one would expect there to be an increase in the deflexion/flexion of the cantilever. In addition, I predict that proportionality will also occur

Following tables and graphs show the result of the experiment. The tables will demonstrate the experimental and theoretical deflection for each case. The graphs will show the relationship between the load applied and deflection, in addition to compare the experimental deflection and theoretical deflection.

3.)Generation of pu – mu interaction curves: The magnitude of Pu determines the neutral axis. On location of the neutral axis the strain distribution is known. This can then be used to solve for the value of Pu and the ultimate moment Mu. It is therefore obvious that the solution to the above set of equations can be found as a closed form solution. This is because the location of the neutral axis is required for the calculation of the normal force Pu, while the value of Pu is itself required for the location of the neural axis.For the purpose of developing the interaction curves the location the neutral axis is assumed and the values of the normal force and the moment are calculated. The neutral axis is then changed to calculate a new set of Pu and Mu. This is repeated to get the interaction curves of PuVs Mu. The figure no. 1 shows the interaction curve for d/Dfrom were area of steel is determine. Following steps are followed: