Description
The Diaphragm apparatus allows students to examine the effect of pressure on the surface profi le of a diaphragm. They can also determine the distribution of circumferential and radial strains across its diameter. A sturdy base contains all parts of the Diaphragm apparatus. This forms a compact product, ideal for use on a workbench. Two heavy fl anges clamp the edge of the diaphragm to provide built-in edge conditions. The area directly under the diaphragm contains oil. Eight strain gauges are cemented to the top surface of the diaphragm in various positions and at different radii. Each strain gauge circuit is a full bridge, with high-stability resistors. The signals from each strain gauge are shown on a digital display. A digital dial gauge is fitted to a digital position indicator. The dial gauge can be traversed across the diaphragm to measure its surface profile. Both instruments can connect to optional Versatile Data Acquisition System (VDAS®). Students use a hydraulic pump to increase the oil pressure under the diaphragm. They record the strain readings and diaphragm profile at different pressures. The results can be taken by hand using the in-built display and pressure gauge and results plotted by hand. Alternatively, the student can use VDAS® to capture the data and plot the relevant graphs and export data. A user guide is supplied with the Diaphragm apparatus. The guide includes full details of the equipment, detailed experiment procedures, theory and results. For quick and reliable tests, optional VDAS® gives accurate real-time data capture, monitoring and display, calculation and charting of all important readings on a computer (computer not included).
Learning Outcomes
Experiments possible with this apparatus include the effect of pressure on:
• Surface profile – the results are presented as a non dimensional curve
• Radial and circumferential strains
• Radial and circumferential strain gradients across the diaphragm
Experimental measurements are compared with theory.
The student is encouraged to use their results to determine the accuracy of the location of the strain gauges.
Specifications
ATICO is committed to a programme of continuous improvement; hence we reserve the right to alter the design and product specification without prior notice.
Net dimesion and weight: 700 mm x 307 mm x 290 mm high and 20 kg
Approximate packed dimensions and weight: 0.25 m3 and 30 kg
Oil : Hydraulic Oil 5
Diaphragm material : Aluminium alloy
Diaphragm mnominal thickness : 3.0 mm
Diaphragm effective diameter : 200 mm
Pressure : Displayed by Bourdon gauge, with output for VDAS®
Surface profile measurement: By digital indicators, with output for VDAS®
Strain: Measured by electrical resistance gauges and displayed digitally, with output for VDAS®
Operating Conditions
Operating environment:
Laboratory
Storage temperature range:
–25°C to +55°C (when packed for transport)
Operating temperature range:
+5°C to +40°C
Operating relative humidity range:
80% at temperatures < 31°C decreasing linearly to 50% at 40°C
