Jerid Sutton Daniel Smith

 To prove an already employed analysis tool, improve it, or create new analysis tools for joints and fasteners. In doing this we would predict load distribution through the fasteners in the joint.  Being able to predict load transfer at a fastener could be very useful to a stress analyst.

 Load Distribution  Fastener arrangement and spacing has a major effect on the distribution of a load

 If the fastener is bigger in diameter it attracts more of the load  In a flexible joint the first fastener transfers the most load  Fastener configuration effects load distribution

 Aluminum (2024-T3)  ½” to 2” total joint thickness  Fasteners 1. Bolts and Nuts (Hi-Loks) 2. Rivets 3. 3/16” to 3/8” diameters 4. Materials – titanium, A-286 Steel, Nickel Alloy

 Availability of testing equipment  Using Aluminum 2024-T1 1/8” and 3/16” Plate  Blind Rivets  3/16” Diameter  Aluminum  Stainless Steel  Titanium

 Nut and Bolt Combination  ¼”-3/16” Diameter  Stainless Steel  Grade 8  Grade 6

 Standard Tension Tests  11,000 lb Maximum Tensile Force  Software  Pro-Mechanica FEA  ALGOR FEA

 Search ASTM standards for tension testing procedures  Predict stress in predetermined specimen using stress and strain  Verify testing device by comparing results to predicted ultimate strength of the specimen

 1040 Cold-drawn Steel  Stress = Force/Area  Sample Calculation  6,250 lb/(.25in X.5in) = 50,000 psi  Compare with Pro-Mechanica Analysis Results

 Two partial dog-bone specimen held together by inline rivets  Requires Spirit to assemble the specimen  Surface finish has to be capable of adhering a strain gage

 Measured every specimen cut out and scrapped anything that was not within.1” of tolerance  Some holes that were drilled didn’t properly line up so those parts were scrapped as well  When parts were cut out and drilled we had to debur edges so there were no sharp corners for safety reasons

 Yield Strength or 2024 = 47000psi  YS = F/6x[d 2 /4]  = F/6x(.250) 2 /4  F = 14,628lbs to shear rivets  The Zwick tensile test machine can only go to 10,000lbs safely so it is not possible to break the specimen here.

 Fundamentally, all strain gages are designed to convert mechanical motion into an electronic signal. A change in capacitance, inductance, or resistance is proportional to the strain experienced by the sensor. If a wire is held under tension, it gets slightly longer and its cross-sectional area is reduced. This changes its resistance (R) in proportion to the strain sensitivity (S) of the wire's resistance.

STRAIN READING

PREPARING FOR TESTING

STRAIN GAGES

RECORDING STRAIN

TEST PIECE IN MACHINE

CLOSE-UP OF TEST PIECE IN MACHINE

Force (lbs) Force (N) Strain Strain Concentrations (sum) Gage readings are to Elongation (mm)

 At this point we have a few excel programs from Spirit but need their assistance in manipulating them to work with our results.  The excel program supplied by Spirit is made to correspond with many different numbers of fasteners and we do not know yet how to get it to calculate the load at only 3.

MaterialProvided ByCost to us.072 PlatePSUFree RivetsSpiritFree Strain GagesPSUFree EquipmentPSU & SpiritFree

Week 1Week 2Week 3Week 4 Tasks October Concept Literature Review Pricing November Budget Funding Proposal Final Proposal December Concept ReviewBreak

Week 1Week 2Week 3Week 4 Tasks January Concept Review Design And Review February Design And Review Manufacturing Plan March Manufacturing Break Spirit Conciliation 1 Break April Strain Gage Application And Testing Testing Results Review May Spirit Conciliation 2