a) Types of loading i) Static load: applied slowly, so that it causes no vibrational or dynamic effects ii) Dynamics load (1) Impact load: loads are applied and removed suddenly (a) two objects collide (b) falling object strikes a structure (2) Fluctuating load: persist for long periods of time and continuously vary in intensity (a) rotating machinery, traffic, wind gusts, water waves, earthquakes, and manufacturing processes…
) The work done by the load is equal to the area below the load-displacement curve c) When the load stretches the bar, strains are produced. The presence of these strains increases the energy level of the bar itself. Strain energy is defined as the energy absorbed by the bar during the loading process. From the principle of…
are positive in tension and shear stresses are positive when they tend to produce counterclockwise rotation of the material Angle is between the x-axis and the normal to the section b.)These equations are valid for any material, whether it behaves linearly or nonlinearly, elastically or inelastically. a) Maximum Normal and Shear Stresses i) The maximum normal Stress occurs at and is …
) of prismatic bars subjected to tensile or compressive centroidal loads is proportional to both the load (P) and the length (L) of the bar, and inversely proportional to the axial rigidity (EA) of the bar; this relationship is called a force-displacement relation a) The summation of the displacements of the individual segments of a non-prismatic bar equals…
1.) Shear stress acting on a positive face of an element is positive if it acts in the positive direction of one of the coordinate axes and negative if it acts in the negative direction of an axis. Shear stress acting on a negative face of an element is positive if it acts in the negative direction of an axis and negative if it acts in a positive direction. 2.) Shear strain in an element is positive…
is a measure of the distortion, or change in shape, of the element and is called the shear strain. b.) Because shear strain is an angle, it is usually measured in degrees or radians.
i. Direct shear (or simple shear) in which the shear stresses are created by the direct action of the forces in trying to cut through the material ii. Shear stresses also arise in an indirect manner when members are subjected to tension, torsion, and bending Equality of Shear Stresses on Perpendicular Planes i. Shear stresses on opposite (and…
Elasticity : Property of a material, by which it returns to its original dimension duringunloading Partially elastic : During unloading the bar returns partially to its original shape i. Residual elongation of the bar is called the permanent set and the strain associated with that is known as residual strain Plasticity : characteristic of a material by which it undergoes inelastic strains beyond the strain at…
i. The modulus of elasticity is the slope of stress-strain diagram in the linearly elastic region ii. Valid upto proportional limit only. Practically elastic and proportional limit are same. 1. Poisson’s Ratio, i. The lateral strainat any point in a bar is proportional to the axial strain at that same point if the material is linearly elastic. ii. for all practical purpose
i. When a material such as aluminum does not have an obvious yield point and yet undergoes large strains after the proportional limit is exceeded ii. Offset Method – A straight line is drawn on the stress-strain diagram parallel to the initial linear part of the curve (Fig. 1-14) but offset by some standard strain, such as 0.002…