Answer Happy

QUESTION 1 Choose the statement below about principal planes of a stressed element that is the most correct. Principal planes are the orientation of a stressed element where the magnitude of the stress is the largest The principal planes occur at orientations where both normal stress and shear stress are maximum. Principal planes occur at orientations where there is no shear stress. Principal planes occur when normal stress is zero. QUESTION 2 Choose the statement below about strain energy that is the most correct. Superposition does not hold for strain energy because the application of more than one load on a body results in work being done to the system that is not unique to each load. Superposition does not hold for strain energy because it does not result in stresses which can be summed. Superposition does not hold for strain energy because it results in stresses in different directions and of different types (i.e. normal and shear), which cannot be summed under superposition. Superposition does not hold for strain energy because of Castigliano's theorem. QUESTION 3 Choose the statement below about orthotropic and anisotropic materials that is the most correct. Orthotropic materials have mechanical properties which are not dependant upon direction, whereas Anisotropic material's properties do depend upon direction. Orthotropic materials are a sub-category of Anisotropic materials, and have mechanical properties that are dependant upon direction Anisotropic materials have mechanical properties that are dependant upon direction. Orthotropic materials have mechanical properties that are dependant upon 3 planes of symmetry. Anisotropic materials have mechanical properties that are not dependant upon direction, wheras Orthotropic material's mechanical properties are dependant upon direction.
QUESTION 4 Which of the below statements is not a basic assumption for thin plates? Stress in the direction orthogonal to the plate's midsurface is negligible. Deflection is small relative to plate thickness. Lines normal to the midsurface do not distort, and remain normal upon loading Strain does not occur at the midsurface Internal shear forces are zero QUESTION 5 Equilibrium of a stressed element means that the number of unique stresses in a 3D stresses is reduced from 9 to 6. True False QUESTION 6 Strain Rosettes are used to measure strains in 3 directions on a surface, which can be used to determine ex, €y and Yxy in-plane with that surface. True False QUESTION 7 The 3 Mohr's Circles for 3 dimensions relate to 3 mutually perpendicular (e. orthogonal) directions. True False