But it also common practice to state it as the ratio of two length units - like m/m or in/in. Note that strain is a dimensionless unit since it is the ratio of two lengths. Young's modulus can be used to predict the elongation or compression of an object when exposed to a force.Shear strain - change in angle between two line segments originally perpendicularĮ = Young's modulus (Modulus of Elasticity) (Pa, (N/m 2), psi (lb f/in 2)).Normal strain - elongation or contraction of a line segment.Strain is defined as "deformation of a solid due to stress". Τ = shear stress (Pa (N/m 2), psi (lb f/in 2))į p = shear force in the plane of the area (N, lb f)Ī shear force lies in the plane of an area and is developed when external loads tend to cause the two segments of a body to slide over one another. Stress parallel to a plane is usually denoted as " shear stress" and can be expressed as The dressed size of the post is 5.5 x 5.5 in and the compressive stress can be calculated as = 127 (MPa) Example - Force acting on a Douglas Fir Square PostĪ compressive load of 30000 lb is acting on short square 6 x 6 in post of Douglas fir. The stress in the rod can be calculated as Example - Tensile Force acting on a RodĪ force of 10 kN is acting on a circular rod with diameter 10 mm. 1 kip = 4448.2216 Newtons (N) = 4.4482216 kilo Newtons (kN)Ī normal force acts perpendicular to area and is developed whenever external loads tends to push or pull the two segments of a body.a kip is an imperial unit of force - it equals 1000 lb f (pounds-force).Σ = normal stress (Pa (N/m 2), psi (lb f/in 2))į n = normal force acting perpendicular to the area (N, lb f) Tensile or compressive stress normal to the plane is usually denoted " normal stress" or " direct stress" and can be expressed as Tensile or Compressive Stress - Normal Stress shearing stress - stress that tends to shear the material - acts in plane to the stressed area at right-angles to compressive or tensile stress.compressive stress - stress that tends to compress or shorten the material - acts normal to the stressed area.tensile stress - stress that tends to stretch or lengthen the material - acts normal to the stressed area.Stress is the ratio of applied force F to a cross section area - defined as " force per unit area".