Strength of Materials: Questions and Answers Essay Example

ratio The relationship between modulus of elasticity, modulus of rigidity and Poisson’s ratio is given by E=Modulus of elasticity C=Modulus of rigidity Poisson’s ratio  If the strain in three mutually perpendicular directions are ex, ey and ez then what is the value of volumetric strain? =ex+ey+ez = (Px+Py+Pz) =volumetric strain E= young’s modulus Px+Py+Pz = stresses along x,y z and directions 1/m = poisson’s ratio

State Hooke’s law. Hooke’s law is stated as when a material is loaded within elastic limit, the stress is proportional to the strain produced by stress, or Stress/strain=constant. This constant is termed as modulus of elasticity. 10. Define stress and strain. Stress: The force of resistance per unit area, offered by a body against deformation is known as stress. Mathematically stress is written as f=P/A Where f= stress P=external force or load A=cross-sectional area. Unit of stress: stress is represented in N/m2 Strain: The ratio of change in dimension to the orginal dimension when subjected to an external load is termed as strain and is denoted by e. It has no unit.

Define modulus of rigidity The ratio of shear stress to the corresponding shear strain when the stress is within the elastic limit is known as modulus of rigidity or shear modulus and is denoted by C or Gor N = 12. Define modulus of elasticity. The ratio of tensile stress or compressive stress to the corresponding strain is known as modulus of elasticity or young’s modulus and is denoted by E. =E 13. Define Bulk modulus.

When a body is subjected to an uniform direct stress in all the three mutually perpendicular directions, the ratio of the direct stress to the

corresponding volumetric strain is found to be a constant is called as the bulk modulus of the material and is denoted by K. K= 14. Define longitudinal strain and lateral strain. = Longitudinal strain: longitudinal strain is defined as the deformation of the body per unit length in the direction of the applied load. Longitudinal strain= Where L= length of the body. P= tensile force acting on the body dL= increase in the length of the body in the direction of P 15.