For the stress states above determine the required yield strength of the material based on the Tresca and Von Mises Criteria. Tip · What is the role of Principal Stress?

The following creep data were taken on an aluminum alloy at 480 C (900 F) and a constant stress of 2.75 MPa (400 psi). Plot the data as strain versus time,              a)  then determine the steady-state or minimum creep rate. Note: The initial and instantaneous strain is not included.         b)  Identify at what time can a secondary creep region occur and at what time would it end to start the tertiary region in a creep curve:  (see attachment).

Why do we define engineering and true stresses for tension/compression loading but not for shear loading?

Which predicts the lower yield strength for most combinations of applied stress––the Tresca or the von Mises yield criterion? Under what stress conditions are the predictions equal?

can you please find  Normal Stress, tangential Stress and Resultant Stress

Q6/ A material has a true stress -strain curve given by o=Kɛ", derive and calculate the true and engineering ultimate tensile strength of this material. (use : k=689.47kpa , n=0.5)

If a key material has an ultimate strength of 120 ksi and a yield strength of 80 ksi and factor of safety N=2, what would be the design compressive stress in ksi?   (a)  40 ksi   (b)  60 ksi   (c)  160 ksi   (d)  240 ksi

Determine the yield strength of a material required such that the component would not fail when subject to the following stresses sigma1 = 2 MPa and sigma 2= -15 MPa sigma 3 = 10 MPa).  Use a yield criterion that assumes that yield failure will occur when the maximum shear stress in the complex system becomes equal to the limiting shear strength in a simple tensile test.

140 900 1040 Steel Percent cold work = 0 %3D 120 Yield strength = 200 MPa 800 Yield strength = 29 ksi 700 100 600 Brass -80 500 400 60 Copper 300 40 200 10 20 40 30 50 60 70 Percent cold work Tensile strength (MPa) Tensile strength (ksi)

Is the maximum normal stress theory useful to predict the accurate failure of brittle material?