{"id":27817,"date":"2020-11-12T16:11:45","date_gmt":"2020-11-12T16:11:45","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=27817"},"modified":"2023-08-08T09:09:30","modified_gmt":"2023-08-08T09:09:30","slug":"strength","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-engineering\/materials-science\/material-properties\/strength\/","title":{"rendered":"Strength"},"content":{"rendered":"
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\"Stress-strain<\/a>In the mechanics of materials, the strength of a material<\/strong> is its ability to withstand an applied load without failure or plastic deformation. The strength\u00a0of materials<\/strong> considers the relationship between the external loads<\/strong> applied to a material and the resulting deformation<\/strong> or change in material dimensions. In designing structures and machines, it is important to consider these factors so that the material selected will have adequate strength to resist applied loads or forces and retain its original shape. The strength\u00a0of a material<\/strong> is its ability to withstand this applied load without failure or plastic deformation.<\/p>\n

However, we must note that the load which will deform a small component will be less than the load to deform a larger component of the same material. Therefore, the load (force) is not a suitable term<\/strong> for strength<\/strong>. Instead, we can use the force (load) per unit of area<\/b> (\u03c3 = F\/A), called stress<\/strong>, which is constant (until deformation occurs) for a given material regardless of the size of the component part. In this concept, strain<\/strong> is also a very important variable since it defines the deformation of an object. In summary, the mechanical behavior of solids is usually defined by constitutive stress-strain relations.<\/b> A deformation is called elastic deformation if the stress is a linear function of strain. In other words, stress and strain follow Hooke\u2019s law<\/strong>. Beyond the linear region, stress and strain show nonlinear behavior. This inelastic behavior is called plastic deformation.<\/p>\n

Stress<\/h2>\n

In mechanics and materials science, stress<\/strong> (represented by a lowercase Greek letter sigma – \u03c3<\/strong>) is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other. At the same time, strain is the measure of the deformation of the material, which is not a physical quantity.<\/p>\n

Although it is impossible to measure the intensity of this stress, the external load and the area to which it is applied can be measured. Stress (\u03c3)<\/strong> can be equated to the load per unit area or the force (F) applied per cross-sectional area (A) perpendicular to the force as:<\/p>\n

\"stress<\/a><\/p>\n

When a metal is subjected to a load (force), it is distorted or deformed, no matter how strong the metal or light the load. If the load is small, the distortion will probably disappear when the load is removed. The intensity, or degree, of distortion, is known as strain<\/i><\/strong>. A deformation is called elastic deformation<\/strong> if the stress is a linear function of strain. In other words, stress and strain follow Hooke\u2019s law<\/strong>. Beyond the linear region, stress and strain show nonlinear behavior. This inelastic behavior is called plastic deformation<\/strong>.<\/p>\n

Stress is the internal resistance, or counterforce, of a material to the distorting effects of an external force or load. These counterforces tend to return the atoms to their normal positions. The total resistance developed is equal to the external load.<\/p>\n

Types of Stress<\/h3>\n

Stresses occur in any material subject to a load or applied force. There are many types of stress<\/strong>, but they can all be generally classified into one of six categories:<\/p>\n