Final answer:
Shear force is the force applied perpendicular to the length of an object and parallel to its cross-sectional area. It causes deformation by sliding the planes within the material parallel to each other.
Step-by-step explanation:
The shear force is the force that is applied perpendicular to the length of an object and parallel across its cross-sectional area. When a shear force acts on an object, such as a bolt, it tends to cause the planes within the material to slide parallel to each other. This force works against the material's shear strength, which is a measure of how resistant the material is to this sliding motion. The equation for shear stress, τ, is τ = F / A, where F represents the force applied and A is the cross-sectional area the force is acting upon. Shear modulus, denoted by S, is a property that measures the material's response to shear stress; it is a coefficient that when multiplied by the shear strain gives the shear stress.
Shear strength is typically about 0.6 times the tensile strength of a material. Tensile strength is the maximum stress a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract. Thus, for steel fasteners and similar materials, the shear strength is a critical factor for design and structural integrity, as it determines how well the material can resist deformation and failure under shear forces.
Shear deformation occurs in response to shear stress, leading to a change in shape of the material without a change in volume. The deformation is illustrated by the shifting of layers in the direction parallel to the forces acting upon it, which is quantified by shear strain. It is important to consider shear stress and deformation when designing structures and selecting materials for mechanical applications, like bolts, where these forces are prevalent.