ME or MEng Master of Engineering Structural Analysis and Materials Science 3

Question 1

The method of sections in truss analysis involves:

Accepted Answer

Cutting the truss and applying equilibrium to one portion

Answer

The method of sections cuts through the truss and applies three equilibrium equations to the free body of one portion, directly finding up to three unknown member forces.

Question 2

Creep in materials refers to:

Accepted Answer

Slow, time-dependent plastic deformation under sustained load

Answer

Creep is the slow, progressive plastic deformation of a material under constant stress, typically significant at temperatures above 0.4 T_m (melting point).

Question 3

In composite materials, the rule of mixtures gives the longitudinal (fiber-direction) Young's modulus as:

Accepted Answer

E_c = E_f·V_f + E_m·V_m

Answer

The rule of mixtures E_c = E_f·V_f + E_m·V_m applies for loading parallel to fibers, assuming equal strain in fiber and matrix (isostrain condition).

Question 4

Castigliano's second theorem states that the deflection at a point in a structure equals:

Accepted Answer

The partial derivative of total strain energy with respect to the applied load at that point

Answer

Castigliano's theorem: δ_i = ∂U/∂P_i, where U is the total strain energy, allows deflection calculations in statically indeterminate and complex structures.

Question 5

Which type of stress causes shear failure along a 45° plane in a uniaxially loaded ductile member?

Accepted Answer

Maximum shear stress

Answer

Maximum shear stress on planes at 45° to the principal stress axes causes slip and shear failure in ductile materials under uniaxial loading.

ME or MEng Master of Engineering Practice Test

ME or MEng Master of Engineering Practice Test

ME or MEng Master of Engineering Structural Analysis and Materials Science 3