Engineering Practicum Baltimore Polytechnic Institute M. Scott

• A single iron rod, radius R, has a critical buckling load B and a tensile fracture force Tmax = T

• If you bond together seven such rods in the following two configurations, what will be their new failure loads? Explain your answers.

a)

b)

11-29-10 Drill

Engineering Practicum Baltimore Polytechnic Institute M. Scott

1. ASTM A36 steel has an ultimate tensile strength of 400 MPa and a Young’s Modulus of 200 GPa. If you create 1 m long rods of the following configurations, what will be their critical buckling and tensile fracture loads?

R = 1 cm R = 2 cm Ro = 2 cmRi = 1 cm

R = 1 cm

Additional Problems

AB

C D

Engineering Practicum Baltimore Polytechnic Institute M. Scott

• How would you solve for these two configurations?

Engineering Practicum Baltimore Polytechnic Institute M. Scott

2. With a 5% uncertainty in each measured value, what is the uncertainty that propagates through your calculations to your final answers?

Engineering Practicum Baltimore Polytechnic Institute M. Scott

3. Now at a cost of $1 per pound and a density of 7.8 g/cm3, what is the difference in costs among the four configurations?

R = 1 cm R = 2 cm Ro = 10 cmRi = 7.5 cm

R = 1 cm

Engineering Practicum Baltimore Polytechnic Institute M. Scott

Materials Test Wednesday

• Anything covered in lecture and lab• A couple error/uncertainty problems• Multiple choice, matching, short answer

Engineering Practicum Baltimore Polytechnic Institute M. Scott

Materials ReviewObjectives

1. Review major concepts from materials lecture and materials lab

2. Understand the implications of material properties and tension/compression equations on design

Engineering Practicum Baltimore Polytechnic Institute M. Scott

• Review PowerPoint “U2-2 Materials 2”