Stress Elements

What is the meaning of Plane Stress

• Good auld ordinary stress, no fancy stuff

• No stress on any faces

• No loads on any faces

• No stress on two of the 6 faces

Answer explanation

No streess in one plane (usually the z plane) thus that's no stress on two of the faces

The principle of _____________ allows engineers to break a complex loading scenario down into each applied load separately, analyse their effect one by one and then combine them at the end

Draw the following Nominal (or applied) loads onto the Stress Element shown ;

50 MPa Positive stress on x plane

60 MPa negative stress on y plane

40 MPa negative shear on x faces

What are the correct values of σ_x σ_y and τ_xy in this image ?

• 20, 10 and 30 MPa

• 30, 20 and 10 MPa

• -30, 20 and -10 MPa

• -30, 20 and 10 MPa

Answer explanation

x is compressive thus -20, y is tensile thus +20 and shear acts up in positive y thus +10

Evaluate the angle of the principle plane, θ_p, in this stress element

• -26.6 Degrees

• • 26 .6 Degrees

• -42.6 Degrees

• -53.1 Degrees

Calculate the Von Mises Stress of an element that has values of σ_p1 = - 20 MPa and = σ_p2 - 100 MPa

• 46.1 MPa

• 111.4 MPa

• 91.7 MPa

• • 107.7 MPa

Calculate the Factor of Safety of a material that has a fatigue strength of 280 MPa and a Von Mises strength of 350 MPa

• 0.8

• 1.25

• 70

• 630

Answer explanation

Its the fixed material property divided by the variable or applied stress. Thus its 280 divided by 350