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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Glossary of mechanical engineering | 8/12 | https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering | reference | science, encyclopedia | 2026-05-05T07:51:05.490215+00:00 | kb-cron |
== D == Damping ratio – an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Deformation (engineering) – refers to the change in size or shape of an object. Deformation that is reversible is termed as elastic deformation, while irreversible deformation is termed plastic deformation. Strain is the relative deformation of an infinitesimally small cube of material, and is generally linearly proportional to the forces or stresses acting on the cube while the deformation is elastic. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure by structural analysis. Delamination – is a mode of failure where a material fractures into layers. A variety of materials including laminate composites and concrete can fail by delamination. Design – Design for manufacturability – (also sometimes known as design for manufacturing or DFM), is the general engineering practice of designing products in such a way that they are easy to manufacture. The concept exists in almost all engineering disciplines, but the implementation differs widely depending on the manufacturing technology. Diesel engine – (also known as a compression-ignition or CI engine), named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to the mechanical compression (adiabatic compression). Differential –A differential is a gear train with three shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average. Dimensionless number – a quantity to which no physical dimension is assigned. Dimensionless quantities are widely used in many fields, such as mathematics, physics, chemistry, engineering, and economics. Diode – a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Diode laser – Docking sleeve – Drafting – Drifting – Driveshaft – a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. Dynamics – the branch of classical mechanics that is concerned with the study of forces and their effects on motion. Dynamometer – a device for simultaneously measuring the torque and rotational speed (RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated.