A strain gauge mounted at a potentially critical point in a steel part has recorded the stress history shown below during 20 seconds of typical use. Identical parts have been fatigue tested under constant amplitude loading with R = -1 to give an endurance limit of 60 ksi and a fatigue strength of 140 ksi at N = 1000 cycles. The steel used has an ultimate strength of 165 ksi. Estimate the fatigue life of the part under typical use. How much will the fatigue life in problem 3 (above) be reduced if a mean stress of 10 ksi is added to the stress history given?

The track curves on the Transnet railway line between Belfast and Steelport in the Limpopo province are heavily corrugated. Explain how you would use FEM to determine the following parameters: i) Total corrugation frequency. ii) Lateral vibrations. ii) Fatigue stresses on the rails.

QUESTION 1 Predict the fatigue strength (ksi) at N=1000 cycles for a fatigue test specimen of a steel whose tensile strength is 125 ksi

For a given homogeneous, isotropic, linearly elastic material, E = 15e6 psi and v = 0.3. Solve for the shear modulus. 2.1.1 Homogeneous, isotropic, linearly elastic materials For specimens undergoing small deformations, the stress-strain diagram often ex- hibits a linear behavior. Although this is a very crude approximation to the behavior of actual materials, it is a convenient assumption that is often used for preliminary evaluation. A linear relationship between stress and strain can be expressed as 01 = E €1, (2.1) where the coefficient of proportionality, E, is called Young's modulus or modulus of elasticity. Since strains are non-dimensional quantities, this coefficient has the same units as stress quantities, i.e., Pa. This linear relationship is known as Hooke's law. The elongation of a bar in the direction of the applied stress is accompanied by a lateral contraction that is also proportional to the applied stress. The resulting defor- mations for this uniaxial state of stress…

a rectangular stepped bar is shown. the bar is loaded in bending. determine the fatigue stress concentration factor if the ultimate stress of the material is 690 mPa. please inlcude how to calculate the notch sensitivity.

1. A steel rotating-beam specimen has an ultimate strength of 1600 MPa. It is tested at a completely reversed stress amplitude of 900 MPa. The life of the specimen is ( _) cycles.

A steel rotating-beam test specimen has an ultimate strength, Sut, of 120 kpsi. Estimate the life of the specimen if it is tested at a completely reversed stress amplitude, Orev, of 74 kpsi. Take the value of the fatigue strength fraction, f, from Fig. 6-23. The life of the specimen is cycles.

A resistance, wire strain gauge with a gauge factor of 3 is bonded to a steel structural e subjected to a stress of 200 MN/m² The modulus of elasticity of steel is 400 GN/m² Calculate the % change in the value of the gauge resistance due to the applied stress

A cylindrical steel bar 8 mm in diameter is loaded 1000 cycles per day with a load of 15560 N.  How long until fatigue failure takes place?  Note: stress = force/area   Group of answer choices The bar should not fatigue. The bar will fail in one cycle. 100 days 1000 days