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Bending stress in beams is caused by a force applied perpendicular to the axis of the beam, resulting in a bending or flexural deformation. Shear stress, on the other hand, is caused by a force applied parallel to the cross-sectional area of the beam, resulting in a shearing or sliding deformation. In simple terms, bending stress affects the top and bottom surfaces of a beam, while shear stress affects the sides of a beam.
The maximum bending stress in a beam can be calculated using the formula σ = My/I, where σ is the bending stress, M is the moment applied to the beam, y is the distance from the neutral axis to the point of interest, and I is the moment of inertia of the cross-sectional area of the beam.
The neutral axis in a beam is an imaginary line along the cross-section of the beam where there is no stress or deformation when a bending moment is applied. It divides the cross-section into a compression zone and a tension zone, with the compression zone being above the neutral axis and the tension zone below it.
The material of a beam plays a significant role in its strength and ability to withstand bending and shear stresses. Different materials have different properties such as yield strength, modulus of elasticity, and ductility, which affect their ability to resist deformation and failure under load. Generally, materials with higher strength and stiffness, such as steel, are better suited for beams compared to weaker materials like wood.
Normal stress in beams is caused by axial forces or tension/compression loads, resulting in a change in the length of the beam. Shear stress, as mentioned earlier, is caused by lateral forces or loads applied parallel to the cross-section of the beam. Both types of stress can lead to failure in beams, but they affect the beam in different ways and require different calculations for analysis.