M.O.M

Question 1

Explain the difference between stress and strain and how they are related.

Answer 1

Stress is the force applied per unit area within a material, while strain is the resulting deformation or change in shape, and their relationship is defined by the material’s elastic modulus.

Question 2

Discuss the significance of the elastic modulus in material behavior.

Answer 2

The elastic modulus, representing a material’s stiffness and ability to deform under stress, is crucial in material behavior as it quantifies the relationship between stress and strain and determines how a material responds to applied loads.

Question 3

Describe the concept of axial stress and axial strain in a bar subjected to axial loading.

Answer 3

Axial stress in a bar subjected to axial loading is the force per unit area acting along the axis, causing axial strain, which is the resulting fractional change in length relative to the original length of the bar.

Question 4

Explain the factors influencing the deformation of a bar under axial load.

Answer 4

The deformation of a bar under axial load is influenced by its material properties, specifically the modulus of elasticity, as well as geometric factors such as length and cross-sectional area, which collectively determine the magnitude of axial strain and subsequent elongation or contraction.

Question 5

Define torsional stress and torsional strain

Answer 5

Torsional stress is the shear stress experienced by a shaft subjected to a torque, and torsional strain is the resulting angular deformation or twist per unit length.

Question 6

Define shear stress and shear strain

Answer 6

Shear stress is the force per unit area acting parallel to a surface within a material, while shear strain is the resulting angular deformation or displacement relative to the original position of the material’s particles.

Question 7

Explain the differences between the maximum normal stress theory and the maximum shear stress theory

Answer 7

The maximum normal stress theory compares the maximum normal stress in a material to its yield strength, while the maximum shear stress theory compares the maximum shear stress to the shear strength, each providing different criteria for predicting material failure under various loading conditions.

Question 8

Explain the concept of the von Mises stress criterion

Answer 8

The von Mises stress criterion combines normal and shear stresses to assess yielding in a material, considering the combined effect of these stresses to predict failure based on an equivalent stress measure.

Question 9

Hectopascal hPa

Answer 9

Pa 10^2

Question 10

Kilopascal kPA

Answer 10

Pa 10^3

Question 11

Megapascal mPA

Answer 11

Pa 10^6

Question 12

Gigapascal gpA

Answer 12

Pa 10^9

Question 13

How to draw shear/moment diagram

Answer 13

1. find all vertical reactions
2. draw as straight lines, unless uniform, then draw curved with slope as 1/load
3. max moment -> shear crosses x
4. moment is straight lines, unless the shear is a gradient load, then curved