The angle of deformation on the sides of an object exposed to shearing stress. Its symbol is φ (the Greek letter phi), and its value will usually be well below 90°.
The modulus of elasticity for a material subjected to compression on all surfaces—that is, volume stress. Bulk modulus is the relationship of volume stress to volume strain, expressed as the ratio between F / A and dV/Vo, wheredV is the change in volume and Vo is the original volume.
A form of stress produced by the action of equal and opposite forces, whose effect is to reduce the length of a material. Compression is a form of pressure. When compressive stress is applied to all surfaces of a material, this is known as volume stress.
A property whereby a material is capable of being deformed far beyond its elastic limit without experiencing rupture—that is, without breaking. Most metals other than cast iron are highly ductile.
A temporary change in shape or size experienced by a solid subjected to stress. Elastic deformation is thus less severe than plastic deformation.
The maximum stress to which a given solid can be subjected without experiencing plastic deformation—that is, without being permanently deformed.
The response of solids to stress.
A principle of elasticity formulated by English physicist Robert Hooke (1635-1703), who discovered that strain is proportional to stress. Hooke's lawcan be written as a formula, F = ks, where F is the applied force, s the resulting change in dimension, and k a constant whose value is related to the nature and size of the object being subjected to stress. Hooke's law applies only when the elastic limit has not been exceeded.
In discussions of elasticity, "length" refers to an object's dimensions on any given plane, thus, it can be used not only to refer to what is called length in everyday language, but also to width or height.
The ratio between a type of applied stress (that is, tension, compression, and shear) and the strain that results in the object to which stress has been applied. Elastic modu li—including Young's modulus, shearing modulus, and bulk modulus—are applicable only as long as the object's elastic limit has not been reached.
A permanent change in shape or size experienced by a solid subjected to stress. Plastic deformation is thus more severe than elasticdeformation.
The ratio of force to surface area, when force is applied in a direction perpendicular to, and in the same direction as, that surface.
A form of stress resulting from equal and opposite forces that do not act along the same line. If a thick hard-bound book is lying flat, and one pushes the front cover from the side so that the covers and pages no longer constitute parallel planes, this is an example of shear.
The modulus of elasticity for an object exposed to shearing stress. It is expressed as the ratio between F / A and φ, where φ (the Greek letter phi) stands for the angle of shear.
The ratio between the change in dimension experienced by an object that has been subjected to stress, and the original dimensions of the object. The formula for strain is d L / L o , where d L is the change in length and L o the original length. Hooke's law, as well as the various modu li of elasticity, relates strain to stress.
In general terms, stress is any attempt to deform a solid. Types of stress include tension, compression, and shear. More specifically, stress is the ratio of force to unit area, F / A , where F is force and A area. Thus, it is similar to pressure, and indeed, compression is a form of pressure.
A form of stress produced by a force which acts to stretch a material. The adjectival form of "tension" is "tensile": hence the terms "tensile stress" and "tensile strain."
The tension that a material can with stand without rupturing. Due to their high levels of ductility, most metals have a high value of ultimate strength.
The stress that occurs in a material when it is subjected to compression from all sides. The modus of elasticity for volume stress is the bulk modulus.
A modulus of elasticity describing the relationship between stress to strain for objects under either tension or compression. Named after English physicist Thomas Young (1773-1829), Young's modulus is simply the ratio between F / A and δ L / L o —in other words, stress divided by strain.