Conor Walsh
Homework #3
1. See HW3-1(1).mph and HW3-1(2).mph
2. See HW3-1(1).mph and HW3-1(2).mph
3. See HW3-3(1).mph and HW3-3(2).mph
4. See HW3-4.mw. The data table given in the problem statement is unnecessary, given that we are
estimating friction coefficients assuming a purely adhesive model with plastic deformation. This
model predicts all friction coefficients to be approximately equal to 1/6, which is obviously not the case
given the variety of experimentally determined friction coefficients. This model requires additional
factors in order to be able to accurately estimate the values of friction coefficients.
5. See HW3-5.mw. ASTM A517 Steel was used for this example. The results indicate that when the
shear strength of the interfacial film is much smaller than that of the bulk material, the resulting
coefficient of friction is very small, but as the film shear strength nears that of the bulk, the resulting
predicted friction coefficient increases dramatically to infinity.
6. See HW3-6.mw.