Strength of material(SOM)
Strength of material(SOM):
strength of materials,
measurement in engineering of the capacity of metal, wood, concrete, and other materials to withstand stress and strain. Stress is the internal force exerted by one part of an elastic body upon the adjoining part, and strain is the deformation or change in dimension occasioned by stress. When a body is subjected to pull, it is said to be under tension, or tensional stress, and when it is being pushed, i.e., is supporting a weight, it is under compression, or compressive stress. Shear, or shearing stress, results when a force tends to make part of the body or one side of a plane slide past the other. Torsion, or torsional stress, occurs when external forces tend to twist a body around an axis. Materials are considered to be elastic in relation to an applied stress if the strain disappears after the force is removed. The elastic limit is the maximum stress a material can sustain and still return to its original form. According to Hooke’s law, the stress created in an elastic material is proportional to strain, within the elastic limit (see elasticity
). In calculating the dimensions of materials required for specific application, the engineer uses working stresses that are ultimate strengths, or elastic limits, divided by a quantity called factor of safety. In laboratories materials are frequently “tested to destruction.” They are deliberately overloaded with the particular force that acts against the property or strength to be measured. Changes in form are measured to the millionth of an inch. Static tests are conducted to determine a material’s elastic limit, ductility, hardness, reaction to temperature change, and other qualities. Dynamic tests are those in which the material is exposed to a combination of expected operating circumstances including impact (e.g., a shell against a steel tank), vibration, cyclic stress, fluctuating loads, and fatigue. Polarized light, X rays, ultrasonic waves, and microscopic examination are some of the means of testing materials.
TYPES OF BEAMS
https://youtu.be/y5tdxcy9FFA Learn: Types of beam: in strength of material, Cantilever beam, Simply supported beams, Overhanging beam, Fixed beams,and Continuous beam. The following are the Important types of beam Types of Beam 1. Cantilever beam, 2. Simply supported beam, 3. Overhanging beam, 4. Fixed beams, and 5. Continuous beam. 1. Cantilever beam A beam which is fixed at one end and free at the other end, is known as cantilever beam. Such beam is shown in Fig. cantilever beam 2. Simply Supported beam A beam supported or resting freely on the supports at its both ends, is known as simply supported beam. Such beam is shown in Fig. Simply Supported beam 3. Overhanging Beam If the end portion of a beam is extended beyond the support, such beam is known as overhanging beam. Overhanging beam is shown in Fig. Over Hanging beam 4. Fixed Beam A beam whose both ends are…
Stresses and Strain
Learn Stresses and strain, unit of stress,Type of stresses,Tensile stress,Compressive stress,Tensile strain,compressive strain,Shear stress and shear strain Stress: The force of resistance per unit area, offered by a body against deformation is known as stress. The external force acting on the body is called the load or force. The load is applied on the body while the stress is induced in the material of the body. A loaded member remains in equilibrium when the resistance offered by the member against the deformation and the applied load are equal. Mathematically stress is written as, \[σ = \frac{P}{ A }\] where σ = Stress (also called intensity of stress), P = External force or load, and A = Cross-sectional area. Strain When a body is subjected to some external force, there is some change of dimension of the body. The ratio of change of dimension of the body to the original dimension…
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Stresses and strain
Simply Supported Beam : Overhang to One Side : Point Load : (Fig. 3.20) Simply supported - a beam supported on the ends which are free to rotate and have no moment resistance Over hanging - a simple beam extending beyond its support on one end. Point loads are concentrated loads applied along the span of a member or the edge of a wall panel. Defining point loads may be accomplished graphically or in the spreadsheets. In this example, one get clear idea how to calculate reactions when a simply supported beam is having point load overhang on one side of the support. Reactions : Taking moments about B, we get (i.e. acting downwards) S.F.D. : Between C and A, S.F. =-W=constant Between A and B, S.F. = The S.F.D. is shown in Fig. 3.20 (b). B.M.D. : Between C and A, Mx=Wx, which gives MC=0 ; MA=Wa. Between A…
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Learn about Simply Supported Beam : Overhang to One Side : Point Load
A beam, Simply Supported Beam : U.D.L. over the whole span is a structural element that primarily resists loads applied laterally to the beam's axis. Its mode of deflection is primarily by bending. Classification based on supports In engineering, beams are of several types: Simply supported - a beam supported on the ends which are free to rotate and have no moment resistance. Structural loads or actions are forces, deformations, or accelerations applied to a structure or its components. Loads cause stresses, deformations, and displacements in structures. Assessment of their effects is carried out by the methods of structural analysis. Excess load or overloading may cause structural failure, and hence such possibility should be either considered in the design or strictly controlled. Simply Supported Beam : U.D.L. over the whole span
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Simply Supported Beam : U.D.L. over the whole span
The effective column length can be defined as the length of an equivalent pin-ended column having the same load-carrying capacity as the member under consideration.The smaller the effective length of a particular column,the smaller its danger of lateral buckling and the greater its load carrying capacity. It must be recognized that column ends in practice are neither perfectly fixed nor perfectly hinged. The designer may have to interpolate between the theoretical values given, to obtain a sensible approximation to actual restraint conditions. Equivalent Lengths of Columns for Various End Conditions S.No. Type Effective Length of member I 1. Effectively held in position and restrained in direction at both ends. 0.67L 2. Effectively held in position at both ends and restrained in direction at one end. 0.85L 3. Effectively held in position at both ends but not restrained in direction L 4. Effectively held in position and restrained in direction…
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Equivalent and effective Lengths of Columns
In this article Learn :cantilever beam Bending moment diagram B.M.D. and shear force diagram S.F.D. of a cantilever beam having point load at the end,several point loads,U.D.L. Over Whole Span ,U.D.L. not over the whole span,U.D.L. from support to some distance,U.D.L. Somewhere on the beam,Combination of Point Loads and U.D.L. BENDING MOMENT AND SHEAR FORCE DIAGRAMS OF A CANTILEVER BEAM A shear force diagram is the graphical representation of the variation of shear force along the length of the beam and is abbreviated as S.F.D. A bending moment diagram is the graphical representation of the variation of he bending moment along the length of the beam and is abbreviated as B.M.D. We will take different cases of beams and loading for plotting S.F. D and B.M.D. Cantilever : Point Load at the End (Fig. 3.8) At section x from the end A, Fx = - W1 and is constant for…
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Bending moment and shear force diagram of a cantilever beam
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Basic concepts of shear force and bending moment
