σ_1 is the only stress to use to find the factor of safety by the maximum normal stress theory of failure
A load is changing on a part from 1,000 lb to 5,000 lb, the average and range loads are
6,000 lb and 4,000 lb
5,000 lb and 1,000 lb
3,000 lb and 2,000 lb
1,000 lb and 5,000 lb
A part is loaded under service stress for 25,000 reversals, then under a higher stress for 35,000 reversals until failure. If the total life under the larger stress alone is 36,000 reversals, what is the estimated life under the service load?
Brittle materials fail in yielding
By applying 10,000 in.lb torque to this non-rotating shaft, the torque reactions are
T1=5,000 in.lb; T2=5,000 in.lb
T1=6,000 in.lb; T2=4,000 in.lb
T1=4,000 in.lb; T2=6,000 in.lb
None of the above
For a ductile material, the yield stress in shear is the same as it is for tension
For a loaded part, the state of stress is σ_x=2,000 psi, σ_y=-8000 psi, τ_xy=0. If σ_yp=45,000 psi, what is the factor of safety using the maximum normal stress theory of failure?
For a safe design in an alternating loading situation by the modified Goodman approach, two equations must be satisfied
For a shaft that is transmitting 145 HP while turning at 1,200 rpm, the torque is
For a shaft under torque, the only type of deformation that will result is the rotation of the cross-sections with respect to each other
For a brittle material, there are two curves for the stress-strain relationship–one for the tension and the other for compression.
If a part fails by yielding, it will sustain permanent deformation
In order to apply one of the failure theories to estimate the factor of safety, we have to
use the state of stress
find the principal stresses
calculate the maximum shear stress
find the yielding stress of the material
Maximum shear theory of failure only applies to brittle materials
Stress concentration factors are functions of
Geometry and type of loading
Stress concentration factors must be applied when we are using brittle materials
The principal stresses for a part are σ_1=20 MPa, σ_2=5 MPa. What is the factor of safety using the Mises Henckey theory of failure if σ_yp=100 MPa?
The shear stress on a cross-section of a shaft under torsion is linearly proportional to its radius
A torque applied to one end of a shaft, while the other end is keyed against rotation. The torque along the shaft will be proportional to the length
Ultimate stress is the same as yielding stress
When solving for the factor of safety in a combined steady and alternating loading situation, stress concentration factors must be applied for both average and range stresses.
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