Transcript
Team Members:Doug Bradley
Dan Ehlke
Strain Test Stand Finite Element Analysis (FEA) vs Physical
Testing School of Technology Lab Cheaply Load of up to 150 lbs Various length/geometry test specimens
Aluminum Frame
Force Application: weights
Plexiglass cover
Clamping system: standard clamp
Electronics: amplifier unit.
Data Output: Digital display of
voltage
Signal Conditioning: Tare function
to exclude the influence of
preloads.
Test Specimens: tensile test rods,
in aluminium, copper and brass
Force measurement: manually add
weight values
Determined the most important aspects of the design Accuracy/Precision User-friendliness Safety
Functional decomposition identified key parts
Closest to current SofT design
Leverage based sample holding system
Hanging weights apply force
Dial gauge measures displacement
Internal electronics for strain gauges
More stable frame design
Uses clamping system to hold sample
Hydraulic cylinder applies force
Dial gauge measures displacement
Internal electronics for strain gauges
Lighter frame design than concept 2
Uses chuck assembly to hold sample
Electronic linear actuator applies force
Dial gauge and internal electronics hookups not shown
Based on the important qualities determined by the QFD
Identified concepts 2 and 3 as best
Uses the stable U-frame (Concept 2)
Chuck assembly used for sample holding (Concept 3)
Pneumatic cylinder for force application (Concept 2)
Dial gauge and internal electronics as standard
Frame is load-bearing A500 Steel Tube 6 in X 4 in, .25 in
thick Top bar for stability
Under smaller loads Steel barstock 1 in diameter Free
Assumptions: ≤ 0.5 in deflection of sample
Calculated bore size ≥ 1.8 in
Next highest pneumatic size: 2.0 in
60 psi pressure source is unreliable, as is pressure gauge
Alternatives
KNOWN SOLVE FOR DIAMETER
F = ForceP = pressureA = Surface area of pneumatic cylinder boreD = Minimum Cylinder Bore DiameterF= 150 lb (10 lb increments)P= 60 lbs/in2
A = ?D = ?
F=pA150 lb = (60 lbs/in2) * AA = 2.5 in2 A = r2
Determine r2.5 in2 = r2
r = 0.89206D = r*2D = 1.784124
Screw Jack Control Constant
Load Cell Precise Measurement Automatic logging
4 jaw chuck
Steel frame
Force Application: Screw jack
Adjustable jack Placement
Clamping System: Four jaw chuck assembly
Adjustable chuck height
Internal Electronics: NI-DAQ 9237
Signal Conditioning: NI-DAQ 9237 &
Labview Software
Data Output: Graph of Strain / Force in
LabView
Test Specimens: 3 crowbars
Dimensions: 42” x 30” x 6
Force measurement: Honeywell Model 53
Load Cell
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