Jerid SuttonDaniel 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. Rivets3. 3/16” to 3/8” diameters4. 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

Manufacturing Plan

Group Name: Spirit Fatigue Testing

Date: 1/31/2007

Oper. # Description Machine Material Time # Parts1 Plate Specimen Water Jet .375 Plate 1hr 40

Cut-outs 2024-T3

2 Drill Fastener Holes Drill Press .375 Plate 2hrs 402024-T3

3 Clean Burred Edges Belt Sander Test Specimen 1hr 40Within Tolerance 2024-T3

4-A Bolting Test Ratchet Test Pieces .5hr 20Specimen Together

4-B Riveting Test Riveting Die Test Pieces 1hr 20Specimen Together

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[d2/4] 47000 = 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) 1000 2000 3000 4000 5000Force (N) 4448 8896 13344 17792 22240

Strain1 411 487 505 530 6512 426 356 219 186 1513 418 267 217 196 1404 262 121 6 50 1255 348 118 41 10 456 21 290 425 551 6777 7 150 245 158 3308 118 246 206 229 2479 40 84 129 145 150

10 21 81 76 90 94

Strain Concentrations (sum)1 411 898 1403 1933 25842 426 782 1001 1187 13383 418 685 902 1098 12384 262 383 389 439 5645 348 466 507 517 5626 21 311 736 1287 19647 7 157 402 560 8908 118 364 570 799 10469 40 124 253 398 548

10 21 102 178 268 362

Gage readings are to 10-5

Elongation (mm) 1.6 2.7 3.6 4.5 5.4

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.

Material Provided By

Cost to us

.072 Plate PSU Free

Rivets Spirit Free

Strain Gages

PSU Free

Equipment PSU & Spirit

Free

Week 1 Week 2 Week 3 Week 4

Tasks

October Concept

Literature Review

Pricing

November Budget

Funding Proposal

Final Proposal

December Concept Review Break Break

Week 1 Week 2 Week 3 Week 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