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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Glossary of mechanical engineering | 12/12 | https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering | reference | science, encyclopedia | 2026-05-05T07:51:05.490215+00:00 | kb-cron |
== Y == Yield point – In materials science and engineering, the yield point is the point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation. Yield strength – or yield stress, is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, making the precise yield point difficult to determine. In such a case, the offset yield point (or proof stress) is taken as the stress at which 0.2% plastic deformation occurs. Yielding is a gradual failure mode which is normally not catastrophic, unlike ultimate failure. Young's modulus – Young's modulus
E
{\displaystyle E}
, the Young modulus or the modulus of elasticity in tension, is a mechanical property that measures the tensile stiffness of a solid material. It quantifies the relationship between tensile stress
σ
{\displaystyle \sigma }
(force per unit area) and axial strain
ε
{\displaystyle \varepsilon }
(proportional deformation) in the linear elastic region of a material and is determined using the formula:
E
=
σ
ε
{\displaystyle E={\frac {\sigma }{\varepsilon }}}
Young's moduli are typically so large that they are expressed not in pascals but in gigapascals (GPa).
== Z == Zero defects – (or ZD), was a management-led program to eliminate defects in industrial production that enjoyed brief popularity in American industry from 1964 to the early 1970s. Quality expert Philip Crosby later incorporated it into his "Absolutes of Quality Management" and it enjoyed a renaissance in the American automobile industry—as a performance goal more than as a program—in the 1990s. Although applicable to any type of enterprise, it has been primarily adopted within supply chains wherever large volumes of components are being purchased (common items such as nuts and bolts are good examples). Zeroth Law of Thermodynamics – If body A is in thermal equilibrium (no heat transfers between them when in contact) with body C, and body B is in thermal equilibrium with body C, then A is in thermal equilibrium with B.
== See also == Mechanical engineering Engineering Glossary of engineering National Council of Examiners for Engineering and Surveying Fundamentals of Engineering Examination Principles and Practice of Engineering Examination Graduate Aptitude Test in Engineering Glossary of aerospace engineering Glossary of civil engineering Glossary of electrical and electronics engineering Glossary of structural engineering Glossary of areas of mathematics Glossary of artificial intelligence Glossary of astronomy Glossary of automotive design Glossary of biology Glossary of calculus Glossary of chemistry Glossary of economics Glossary of physics Glossary of probability and statistics
== References ==
=== Works cited ===