In engineering, deformation (the change in size or shape of an object) may be elastic or plastic.If the deformation is negligible, the object is said to be rigid.
In engineering, deformation (the change in size or shape of an object) may be elastic or plastic.If the deformation is negligible, the object is said to be rigid.
A fishing swivel is a small, usually ball- or barrel-shaped device used in angling to connect sections of fishing lines, consisting of two rings linked via a thrust bearing pivot joint. The line from the rod and reel is tied to the ring at proximal end, and the line leading to the terminal tackles (the hook, lure and/or sinker) is tied to the other ring at the distal end. Snap swivels have a safety pin-like fastener (i.e. "snap hook") linked to at least one of the rings, which allows quick detachment and interchanging of different lures.
The main purpose of the swivel is to allow the two line sections to rotate independently of each other, which allows self-unwinding of any twists formed during line casting and retrieval, preventing undesirable tanglings. This is particularly important for users of monofilament fishing lines that tend to express memory and form coils when released from a fixed-spool reel. A secondary benefit of the fishing swivel is that it may function as a stopper for sliding sinkers, which depending on fishing method may be placed before or after the swivel. Three-way swivels provide an additional ring that serves as a point of connection for side-branching line segments, which are essential for certain line and hook setups.
A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound.
When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred.
Magnesium alloys are mixtures of magnesium (the lightest structural metal) with other metals (called an alloy), often aluminium, zinc, manganese, silicon, copper, rare earths and zirconium. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminium, copper and steel; therefore, magnesium alloys are typically used as cast alloys, but research of wrought alloys has been more extensive since 2003. Cast magnesium alloys are used for many components of modern cars and have been used in some high-performance vehicles; die-cast magnesium is also used for camera bodies and components in lenses.
The commercially dominant magnesium alloys contain aluminium (3 to 13 percent). Another important alloy contains Mg, Al, and Zn. Some are hardenable by heat treatment.
In materials science, slip is the large displacement of one part of a crystal relative to another part along crystallographic planes and directions. Slip occurs by the passage of dislocations on close/packed planes, which are planes containing the greatest number of atoms per area and in close-packed directions (most atoms per length). Close-packed planes are known as slip or glide planes. A slip system describes the set of symmetrically identical slip planes and associated family of slip directions for which dislocation motion can easily occur and lead to plastic deformation. The magnitude and direction of slip are represented by the Burgers vector, b.
An external force makes parts of the crystal lattice glide along each other, changing the material's geometry. A critical resolved shear stress is required to initiate a slip.
Drawing is a manufacturing process that uses tensile forces to elongate metal, glass, or plastic. As the material is drawn (pulled), it stretches and becomes thinner, achieving a desired shape and thickness. Drawing is classified into two types: sheet metal drawing and wire, bar, and tube drawing. Sheet metal drawing is defined as a plastic deformation over a curved axis. For wire, bar, and tube drawing, the starting stock is drawn through a die to reduce its diameter and increase its length. Drawing is usually performed at room temperature, thus classified as a cold working process; however, drawing may also be performed at higher temperatures to hot work large wires, rods, or hollow tubes in order to reduce forces.
Drawing differs from rolling in that pressure is not applied by the turning action of a mill but instead depends on force applied locally near the area of compression. This means the maximal drawing force is limited by the tensile strength of the material, a fact particularly evident when drawing thin wires.
In structural geology and diagenesis, pressure solution or pressure dissolution is a deformation mechanism that involves the dissolution of minerals at grain-to-grain contacts into an aqueous pore fluid in areas of relatively high stress and either deposition in regions of relatively low stress within the same rock or their complete removal from the rock within the fluid. It is an example of diffusive mass transfer.
The detailed kinetics of the process was reviewed by Rutter (1976), and since then such kinetics has been used inmany applications in earth sciences.