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Mechanical Engineering剪切模量在固体力学中，剪切模量或刚性模量，用 G（有时用 S 或 μ）表示，是材料弹性剪切刚度的量度，定义为剪切应力与剪切应变之比： G := τ x y γ x y = F A Δ x l...
In solid mechanics, the shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is a measure of the elastic shear stiffness of a material and is defined as the ratio of shear stress to shear strain: G := τ x y γ x y = F A Δ x l...
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 物质的体积模量（ K {\displaystyle K} 或 B {\displaystyle B} 或 k {\displaystyle k} ）是物质抵抗体积压缩的能力的量度。它被定义为无限小的压力增加与由此产生的相对体积减少的比率。其他模量描述材料对其他类型应力的响应（应变）：剪切模量描述对剪切应力的响应，杨氏模量描述对法向（纵向拉伸）应力的响应。对于流体来说，只有体积模量才有意义。对于复杂的各向异性固体（例如木材或纸张），这三个模量不包含足够的信息来描述其行为，必须使用完整的广义胡克定律。固定温度下体积模量的倒数称为等温压缩率。
The bulk modulus ( K {\displaystyle K} or B {\displaystyle B} or k {\displaystyle k} ) of a substance is a measure of the resistance of a substance to bulk compression. It is defined as the ratio of the infinitesimal pressure increase to the resulting relative decrease of the volume. Other moduli describe the material's response (strain) to other kinds of stress: the shear modulus describes the response to shear stress and Young's modulus describes the response to normal (lengthwise stretching) stress. For a fluid, only the bulk modulus is meaningful. For a complex anisotropic solid such as wood or paper, these three moduli do not contain enough information to describe its behaviour, and one must use the full generalized Hooke's law. The reciprocal of the bulk modulus at fixed temperature is called the isothermal compressibility.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 挫屈（buckling）力学称屈曲 ，土木工程称为挫屈；是指细长杆件受到压力时，发生弯曲变形的一种现象。由不稳定造成的结构失效称为屈曲失效。理想压杆丧失稳定后，由原来的直线平衡状态变为弯曲平衡状态。理论上，挫曲是因为力学平衡方程式的解出现分岔（解的本质发生改变）所造成的。在受力增加到一定程度之后，物体会出现二种平衡状态，一种是纯压缩力，另一个是有侧向偏移变形的平衡状态。 挫屈的特点是在结构件中，边缘承受压缩应力的元件突然断裂，而元件失效时的压应力小于材料可以承受的终极抗压应力。挫曲的数学分析一般会设法加入方向也是轴向，但和轴有一段位移（偏心）的压应力，以产生原来理想施力时不会受现的二次弯矩。 当在一元件（例如杆件）上的压缩负荷增加，多半最后负荷会大到使元件变形不稳定。若负荷继续加大，会造成明显，甚至无法预测的变形，可能让元件完全无法承受负荷。若变形还不是灾难性的，元件仍会继续承受负载。若挫曲的元件是结构件（例如大楼）中的一部分，会由其他的元件来分担已挫曲元件原来要承受的负载。
In structural engineering, buckling is the sudden change in shape (deformation) of a structural component under load, such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gradually increasing load, when the load reaches a critical level, a member may suddenly change shape and the structure and component is said to have buckled. Euler's critical load and Johnson's parabolic formula are used to determine the buckling stress of a column. Buckling may occur even though the stresses that develop in the structure are well below those needed to cause failure in the material of which the structure is composed. Further loading may cause significant and somewhat unpredictable deformations, possibly leading to complete loss of the member's load-carrying capacity.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 换热器（亦称为热交换器或热交换设备）是用来使热量从热流体传递到冷流体，以满足规定的工艺要求的装置，是对流传热及热传导的一种工业应用。 在一般空调设备中都有换热器，即空调室内机和室外机的冷热排；换热器作放热用时称为“冷凝器”，作吸热用时称为“蒸发器”，冷媒在此二者的物理反应相反。所以家用空调机作为冷气机时，室内机的换热器称作蒸发器，室外机的则称为冷凝器；换做暖气机的角色时，则相反称之。
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 对流是指流体内部的分子运动，是热传与质传的主要模式之一。热对流（亦称为对流传热）是三种主要热传方式中的其中一种（另外两种分别是热传导与热辐射）。
Convection is the transfer of heat through the physical movement of fluids (liquids or gases), where warmer, less-dense material rises and cooler, denser material sinks. It is a single-phase or multiphase fluid flow that occurs spontaneously through the combined effects of material property heterogeneity and body forces on a fluid. When the cause of the convection is unspecified, convection due to the effects of thermal expansion (change in density) and gravity/buoyancy can be assumed (see convection in heat transfer). Convective flow may be transient (such as when a multiphase mixture of oil and water separates) or steady state (see convection cell). The convection may be due to gravitational, electromagnetic or fictitious body forces. Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 热膨胀是物质尺寸随着温度升高而增大的趋势。随着温度的升高（通常不包括相变），物质的长度、面积和体积通常会增加，从而改变其尺寸和密度。物质通常随着温度降低而收缩，这称为热收缩。热膨胀的 SI 单位是开尔文倒数 (K−1)。温度是体内分子平均动能的量度。分子运动得越快，身体的温度就越高。具体来说，它是物质平均分子动能的单调函数。随着粒子能量的增加，它们开始移动得越来越快，削弱了它们之间的分子间力，从而使物质膨胀。
Thermal expansion is the tendency of matter to increase in size with increasing temperature. Matter generally increases in length, area, and volume, changing its size and density, in response to an increase in temperature (usually excluding phase transitions). Substances usually contract with decreasing temperature which is called thermal contraction. The SI unit of thermal expansion is the inverse kelvin (K−1). Temperature is a measure of the average kinetic energy of the molecules in a body. The faster the molecules are moving, the higher that body's temperature is. Specifically, it is a monotonic function of the average molecular kinetic energy of a substance. As the energy in the particles increases, they start moving faster and faster, weakening the intermolecular forces between them and therefore expanding the substance.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在流体力学中，雷诺数（英语：Reynolds number）是流体的惯性力 ρ v 2 L {\displaystyle {\frac {\rho v^{2}}{L}}} 与黏性力 μ v L 2 {\displaystyle {\frac {\mu v}{L^{2}}}} 的比值，它是一个无量纲量。 雷诺数较小时，黏滞力对流场的影响大于惯性力，流场中流速的扰动会因黏滞力而衰减，流体流动稳定，为层流；反之，若雷诺数较大时，惯性力对流场的影响大于黏滞力，流体流动较不稳定，流速的微小变化容易发展、增强，形成紊乱、不规则的紊流流场。
In fluid dynamics, the Reynolds number (Re) is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 阀门（英语：Valve），又称凡而或凡尔，是控制流动中流体介质的流量、流向、压力、温度等的机械装置，阀门是管道系统中基本的部件。阀门管件在技术上与泵一样，常常作为一个单独的类别进行讨论。煤气开关、水龙头是常见最简单的阀门，其他比较常用的尚有蝶阀、球阀、闸阀、减压阀、截止阀、疏水阀、安全阀、针型阀、止回阀、过滤器、电磁阀、隔膜阀、排气阀、流量计、卫生级阀门等等。 阀门可用手动或者手轮、手柄或踏板操作，也可以通过控制来改变流体介质的压力、温度和流量变化。阀门可以对这些变化进行连续或重复的操作，比如在热水系统或蒸汽锅炉安装的安全阀。 在更复杂的控制系统根据外部输入（即调节流经管道不断变化的设置点）的需要采用自动控制阀门。自动控制阀门不需人工操作，根据其输入和设置，使阀门准确控制流体介质的各项要求。
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin valva, which describes the moving part of a door, in turn from volvere, which means to turn or roll. The simplest, and very ancient, valve is simply a freely hinged flap which swings down to obstruct fluid (gas or liquid) flow in one direction, but is pushed up by the flow itself when the flow is moving in the opposite direction. This is called a check valve, as it prevents or "checks" the flow in one direction.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 管流是水力学及流体力学的分支，是指液体在管道的流动，且液体不存在自由表面，也称为内流。存在自由表面的类似流动称为明渠流。管流和明渠流有许多类似之处，但两者的差异主要是在是否有自由表面。管流没有自由表面，因此不会直接受到大气压力的影响，但是会受到管子内水压的影响。 不是所有在封闭管道内的液体流都属于管流，例如雨水排水道就是在封闭管道内，但多半存在自由表面，因此仍属于明渠流。唯一的例外是雨水排水道全满时，不存在自由表面，此时即可视为管流。 管流里的能量常会表示为扬程，由伯努利定律所定义。为了在探讨管流的过程中可以将扬程概念化，管流的图中常会有水力坡线（hydraulic grade line，HGL）。管流会受到摩擦损失的影响，而摩擦损失是由达西–威斯巴哈方程式所定义。
In fluid mechanics, pipe flow is a type of fluid flow within a closed conduit, such as a pipe, duct or tube. It is also called as Internal flow. The other type of flow within a conduit is open channel flow. These two types of flow are similar in many ways, but differ in one important aspect. Pipe flow does not have a free surface which is found in open-channel flow. Pipe flow, being confined within closed conduit, does not exert direct atmospheric pressure, but does exert hydraulic pressure on the conduit. Not all flow within a closed conduit is considered pipe flow. Storm sewers are closed conduits but usually maintain a free surface and therefore are considered open-channel flow. The exception to this is when a storm sewer operates at full capacity, and then can become pipe flow. Energy in pipe flow is expressed as head and is defined by the Bernoulli equation.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 搅拌器是一种通过摇动或搅拌使物体运动的装置或机构。搅拌机有多种类型，包括洗衣机搅拌器（来回旋转）和磁力搅拌器（包含在磁场中旋转的磁棒）。搅拌器有多种尺寸和品种，具体取决于应用。一般来说，搅拌器通常由叶轮和轴组成。叶轮是位于连接到轴的管子或导管内的转子。它有助于增强压力以实现流体的流动。现代工业搅拌器结合了过程控制，以更好地控制混合过程。
An agitator is a device or mechanism to put something into motion by shaking or stirring. There are several types of agitation machines, including washing machine agitators (which rotate back and forth) and magnetic agitators (which contain a magnetic bar rotating in a magnetic field). Agitators can come in many sizes and varieties, depending on the application. In general, agitators usually consist of an impeller and a shaft. An impeller is a rotor located within a tube or conduit attached to the shaft. It helps enhance the pressure in order for the flow of a fluid be done. Modern industrial agitators incorporate process control to maintain better control over the mixing process.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 压痕是硬表面的永久压痕。它以布氏硬度计命名，其中以预设的力将小球推向坚硬的表面，标记的深度和直径表示该表面的布氏硬度。压痕是表面的永久塑性变形，通常发生在两个接触表面静止（例如滚动元件和轴承滚道）并且超过材料屈服强度时。布氏硬度处理是不可取的，因为这些零件通常与非常接近的其他零件配合。非常小的压痕很快就会导致操作不当，例如颤振或过度振动，进而加速其他形式的磨损，例如剥落，最终导致轴承失效。
Brinelling is the permanent indentation of a hard surface. It is named after the Brinell scale of hardness, in which a small ball is pushed against a hard surface at a preset level of force, and the depth and diameter of the mark indicates the Brinell hardness of the surface. Brinelling is permanent plastic deformation of a surface, and usually occurs while two surfaces in contact are stationary (such as rolling elements and the raceway of a bearing) and the material yield strength has been exceeded. Brinelling is undesirable, as the parts often mate with other parts in very close proximity. The very small indentations can quickly lead to improper operation, such as chattering or excess vibration, which in turn can accelerate other forms of wear, such as spalling and ultimately, failure of the bearing.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 压力交换器将压力能从高压流体流传递至低压流体流。许多工业过程在高压下运行并产生高压废物流。向这种过程提供高压流体的一种方式是使用压力交换器将废液压力转移到低压流。一种特别有效的压力交换器是旋转压力交换器。该装置使用圆柱形转子，其纵向管道平行于其旋转轴线。转子在两个端盖之间的套筒内旋转。压力能直接从转子管道中的高压流传递到低压流。留在管道中的一些流体充当阻碍流之间混合的屏障。
A pressure exchanger transfers pressure energy from a high pressure fluid stream to a low pressure fluid stream. Many industrial processes operate at elevated pressures and have high pressure waste streams. One way of providing a high pressure fluid to such a process is to transfer the waste pressure to a low pressure stream using a pressure exchanger. One particularly efficient type of pressure exchanger is a rotary pressure exchanger. This device uses a cylindrical rotor with longitudinal ducts parallel to its rotational axis. The rotor spins inside a sleeve between two end covers. Pressure energy is transferred directly from the high pressure stream to the low pressure stream in the ducts of the rotor. Some fluid that remains in the ducts serves as a barrier that inhibits mixing between the streams.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 环绕盘管是一种能量回收热交换器，最常放置在空气处理系统的送风和排气流中，或工业过程的废气中，以回收热能。一般来说，它是指出于安全或实用原因，用于在不直接连接的两个流之间传递热量的任何中间流。它也可以称为循环回路、泵循环盘管或液体耦合热交换器。
A run-around coil is a type of energy recovery heat exchanger most often positioned within the supply and exhaust air streams of an air handling system, or in the exhaust gases of an industrial process, to recover the heat energy. Generally, it refers to any intermediate stream used to transfer heat between two streams that are not directly connected for reasons of safety or practicality. It may also be referred to as a run-around loop, a pump-around coil or a liquid coupled heat exchanger.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 质心为多质点系统的质量中心。若对该点施力，系统会沿着力的方向运动、不会旋转。质点位置对质量加权取平均值，可得质心位置。以质心的概念计算力学通常比较简单。质心对应的英文有 center of mass 与 barycenter（或 barycentre，源自古希腊的 βαρύς heavy + κέντρον centre）。后者指两个或多个物体互绕物体的质量中心。 Barycenter 在天文学和天文物理上是很重要的一个观念。从一个物体的质心转移一个距离至彼此的质心，可以简化成二体问题来进行计算。在两个天体当中，有一个比另一个大许多的情况下（在相对封闭的环境），质心通常会位于质量较大的天体之内。因而较小的天体会在轨道上绕着共同的质心运动，而较大的仅仅只会略微"抖动"。地月系统就是这样的状况，俩者的质心距离地球的中心4,671公里，而地球的半径是6,378公里。当两个天体的质量差异不大时，质心通常会介于两者之间，而这两个天体会呈现互绕的现象。冥王星和它的卫星夏戎，还有许多双小行星和联星，都是这种情况的例子。木星和太阳的质量相差虽然超过1,000倍，但因为它们之间的距离较大，也是这一类型的例子。 在天文学，质心坐标是非转动坐标，其原点是两个或多个天体的质心所在。国际天球参考系统是质心坐标之一，它的原点是太阳系的质心所在之处。 在几何学，质心不等同于重心，是二维形状的几何中心。
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point) is the unique point at any given time where the weighted relative position of the distributed mass sums to zero. For a rigid body containing its center of mass, this is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for the application of Newton's laws of motion.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 自由运动方程是一个微分方程，它描述在没有外力但仅存在惯性力的情况下的机械系统，具体取决于参考系的选择。
A free motion equation is a differential equation that describes a mechanical system in the absence of external forces, but in the presence only of an inertial force depending on the choice of a reference frame.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 拉梅应力椭球体是莫尔圆的替代方案，用于以图形方式表示某一点的应力状态。椭球体的表面表示作用在通过连续体中给定点的所有平面上的所有应力矢量的端点轨迹。换句话说，连续体中给定点处的所有应力矢量的端点都位于应力椭球表面上，即，从位于所考虑的材料点处的椭球中心到椭球表面上的点的半径矢量等于穿过该点的某个平面上的应力矢量。在二维中，表面由椭圆表示。一旦知道了椭球体的方程，就可以获得通过该点的任何平面的应力矢量的大小。
Lamé's stress ellipsoid is an alternative to Mohr's circle for the graphical representation of the stress state at a point. The surface of the ellipsoid represents the locus of the endpoints of all stress vectors acting on all planes passing through a given point in the continuum body. In other words, the endpoints of all stress vectors at a given point in the continuum body lie on the stress ellipsoid surface, i.e., the radius-vector from the center of the ellipsoid, located at the material point in consideration, to a point on the surface of the ellipsoid is equal to the stress vector on some plane passing through the point. In two dimensions, the surface is represented by an ellipse. Once the equations of the ellipsoid is known, the magnitude of the stress vector can then be obtained for any plane passing through that point.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 当流体在物体周围流动时，流体会对物体施加力。升力是垂直于迎面流动方向的力的分量。它与阻力形成对比，阻力是平行于流动方向的力的分量。升力通常沿向上方向作用，以抵抗重力，但它可以沿垂直于流动的任何方向作用。如果周围的流体是空气，则该力称为空气动力。在水或任何其他液体中，它被称为水动力。动态升力与流体中的其他类型的升力不同。空气静力升力或浮力，其中内部流体比周围流体轻，不需要运动，并且由气球、飞艇、飞船、船只和潜艇使用。
When a fluid flows around an object, the fluid exerts a force on the object. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it may act in any direction perpendicular to the flow. If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a hydrodynamic force. Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatic lift or buoyancy, in which an internal fluid is lighter than the surrounding fluid, does not require movement and is used by balloons, blimps, dirigibles, boats, and submarines.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在连续介质物理学中，具有记忆的材料，也称为具有遗传效应的材料，是一类其本构方程包含对热力学、动力学、电磁或其他类型状态变量的过去历史的依赖的材料。
In continuum physics, materials with memory, also referred as materials with hereditary effects are a class of materials whose constitutive equations contains a dependence upon the past history of thermodynamic, kinetic, electromagnetic or other kind of state variables.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 艾萨克·牛顿的空气阻力正弦平方定律是一个公式，该公式意味着浸入移动流体中的平板上的力与攻角正弦的平方成正比。尽管牛顿本人没有分析平板上的力，但他用于球体、圆柱体和圆锥体的技术后来被应用到平板上，得出了这个公式。 1687 年，牛顿在他的《数学原理》第二卷中专门讨论了流体力学。该分析假设流体粒子在撞击板之前以均匀的速度移动，然后在接触后沿着板的表面运动。假定通过板上方和下方的颗粒不受影响，并且忽略任何颗粒与颗粒的相互作用。
Isaac Newton's sine-squared law of air resistance is a formula that implies the force on a flat plate immersed in a moving fluid is proportional to the square of the sine of the angle of attack. Although Newton did not analyze the force on a flat plate himself, the techniques he used for spheres, cylinders, and conical bodies were later applied to a flat plate to arrive at this formula. In 1687, Newton devoted the second volume of his Principia Mathematica to fluid mechanics. The analysis assumes that the fluid particles are moving at a uniform speed prior to impacting the plate and then follow the surface of the plate after contact. Particles passing above and below the plate are assumed to be unaffected and any particle-to-particle interaction is ignored.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 气动弹性是物理学和工程学的一个分支，研究弹性体暴露于流体流动时发生的惯性力、弹性力和空气动力之间的相互作用。气动弹性的研究可大致分为两个领域：静态气动弹性处理弹性体对流体流动的静态或稳态响应，动态气动弹性处理弹性体的动态（通常是振动）响应。飞机很容易受到气动弹性效应的影响，因为它们需要重量轻，同时承受较大的气动载荷。
Aeroelasticity is the branch of physics and engineering studying the interactions between the inertial, elastic, and aerodynamic forces occurring while an elastic body is exposed to a fluid flow. The study of aeroelasticity may be broadly classified into two fields: static aeroelasticity dealing with the static or steady state response of an elastic body to a fluid flow, and dynamic aeroelasticity dealing with the body's dynamic (typically vibrational) response. Aircraft are prone to aeroelastic effects because they need to be lightweight while enduring large aerodynamic loads.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在结构工程中，Bouc-Wen 迟滞模型是通常用于描述非线性迟滞系统的迟滞模型。它由 Robert Bouc 提出，并由 Yi-Kwei Wen 扩展，他通过产生各种迟滞模式展示了其多功能性。该模型能够以分析形式捕获与多种滞后系统的行为相匹配的一系列滞后循环形状。由于其多功能性和数学上的易处理性，Bouc-Wen 模型受到了欢迎。它已扩展并应用于各种工程问题，包括多自由度 (MDOF) 系统、建筑物、框架、迟滞系统的双向和扭转响应、二维和三维连续体、土壤液化和基础隔离系统。
In structural engineering, the Bouc–Wen model of hysteresis is a hysteretic model typically employed to describe non-linear hysteretic systems. It was introduced by Robert Bouc and extended by Yi-Kwei Wen, who demonstrated its versatility by producing a variety of hysteretic patterns. This model is able to capture, in analytical form, a range of hysteretic cycle shapes matching the behaviour of a wide class of hysteretical systems. Due to its versatility and mathematical tractability, the Bouc–Wen model has gained popularity. It has been extended and applied to a wide variety of engineering problems, including multi-degree-of-freedom (MDOF) systems, buildings, frames, bidirectional and torsional response of hysteretic systems, two- and three-dimensional continua, soil liquefaction and base isolation systems.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在数学中，有界变形函数是一种其分布导数表现不佳的函数，不足以被视为有界变分函数，尽管导数矩阵的对称部分确实满足该条件。有界变形函数被认为是弹塑性体的变形，在材料的数学研究中发挥着重要作用，例如。脆性裂纹演化的 Francfort-Marigo 模型。更准确地说，给定 Rn 的开子集 Ω，如果 u 的对称梯度 ε(u)， ε ( u ) = ∇ u + ∇ u ⊤ 2 {\displaystyle \varepsilon (u)={\frac {\nabla u+\nabla u^{\top }}{2}}} 是有界、对称的 n × n 矩阵值氡测量。
In mathematics, a function of bounded deformation is a function whose distributional derivatives are not quite well-behaved-enough to qualify as functions of bounded variation, although the symmetric part of the derivative matrix does meet that condition. Thought of as deformations of elasto-plastic bodies, functions of bounded deformation play a major role in the mathematical study of materials, e.g. the Francfort-Marigo model of brittle crack evolution. More precisely, given an open subset Ω of Rn, a function u : Ω → Rn is said to be of bounded deformation if the symmetrized gradient ε(u) of u, ε ( u ) = ∇ u + ∇ u ⊤ 2 {\displaystyle \varepsilon (u)={\frac {\nabla u+\nabla u^{\top }}{2}}} is a bounded, symmetric n × n matrix-valued Radon measure.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在地质学中，术语压缩是指指向岩体中心的一组应力。压缩强度是指在发生失效之前可以施加到材料上的最大压缩应力。当最大压应力位于水平方向时，可能会发生逆冲断层，导致该部分地壳缩短和增厚。当最大压应力是垂直时，一段岩石通常会在正断层中破坏，水平延伸并垂直减薄给定的岩石层。压应力也会导致岩石折叠。由于构造板块中的静岩应力很大，构造尺度的变形总是受到净压应力的影响。
In geology, the term compression refers to a set of stresses directed toward the center of a rock mass. Compressive strength refers to the maximum amount of compressive stress that can be applied to a material before failure occurs. When the maximum compressive stress is in a horizontal orientation, thrust faulting can occur, resulting in the shortening and thickening of that portion of the crust. When the maximum compressive stress is vertical, a section of rock will often fail in normal faults, horizontally extending and vertically thinning a given layer of rock. Compressive stresses can also result in the folding of rocks. Because of the large magnitudes of lithostatic stress in tectonic plates, tectonic-scale deformation is always subjected to net compressive stress.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 裂纹扩展方程用于计算循环载荷产生的疲劳裂纹的尺寸。疲劳裂纹的增长可能导致灾难性故障，特别是对于飞机而言。当许多不断增长的疲劳裂纹相互作用时，就被称为广泛的疲劳损伤。通过预测裂纹的大小，裂纹扩展方程可用于确保设计阶段和运行期间的安全。在关键结构中，可以记录载荷并用于预测裂缝的大小，以确保在任何裂缝失效之前进行维护或报废。由于疲劳寿命对裂纹萌生缺陷的尺寸和形状以及部件所承受的假定载荷和实际载荷之间的可变性的敏感性，安全系数用于将预测疲劳寿命缩短为使用寿命。
A crack growth equation is used for calculating the size of a fatigue crack growing from cyclic loads. The growth of a fatigue crack can result in catastrophic failure, particularly in the case of aircraft. When many growing fatigue cracks interact with one another it is known as widespread fatigue damage. A crack growth equation can be used to ensure safety, both in the design phase and during operation, by predicting the size of cracks. In critical structure, loads can be recorded and used to predict the size of cracks to ensure maintenance or retirement occurs prior to any of the cracks failing. Safety factors are used to reduce the predicted fatigue life to a service fatigue life because of the sensitivity of the fatigue life to the size and shape of crack initiating defects and the variability between assumed loading and actual loading experienced by a component.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 疲劳一词在材料科学领域， 意指物件因持续受到动态变化的应力而造成结构劣化。引起疲劳的动态变化应力通常远小于静态的极限拉伸应力或极限屈变应力。疲劳是渐进且局部的结构损坏过程，由于长时间日积月累而产生，所引起的破裂往往在毫无预警的情况下发生，可能直接导致事故（例如空难）的发生，因此相关的预防、检查、处理格外重要。
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure. Fatigue has traditionally been associated with the failure of metal components which led to the term metal fatigue. In the nineteenth century, the sudden failing of metal railway axles was thought to be caused by the metal crystallising because of the brittle appearance of the fracture surface, but this has since been disproved.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 无穷小应变理论（infinitesimal strain theory）也称为无限小应变理论，是连续介质力学中描述固体形变的数学分析法，适用在其形变量远小于物体尺寸（无穷小量）的情形，因此若是均质材料，可以假设材料每一点的结构性质（密度及刚度）都相等，不会随变形而不同。 在此假设下，连续介质力学的方程可以简化。此作法也称为是小形变理论、小位移理论或小位移梯度理论。无穷小应变理论和有限应变理论的假设恰好相反，后者假设形变量没有远小于物体尺寸。 无穷小应变理论常用在土木工程及机械工程中，其中会进行结构的应力分析，而材料是用强度较高的混凝土及钢制成，而结构设计的目标也是在一般结构荷重下，希望其形变量可以降到最小。不过若分析的结构物是较细较薄，较容易变形的元件（例如杆、平板及薄壳），用无限小应变理论来分析就不可靠了。
In continuum mechanics, the infinitesimal strain theory is a mathematical approach to the description of the deformation of a solid body in which the displacements of the material particles are assumed to be much smaller (indeed, infinitesimally smaller) than any relevant dimension of the body; so that its geometry and the constitutive properties of the material (such as density and stiffness) at each point of space can be assumed to be unchanged by the deformation. With this assumption, the equations of continuum mechanics are considerably simplified. This approach may also be called small deformation theory, small displacement theory, or small displacement-gradient theory. It is contrasted with the finite strain theory where the opposite assumption is made. The infinitesimal strain theory has wide applications in engineering.
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View content license ↗ Levi-Mises 方程（也称为流动法则）描述了理想塑性固体的应力和应变之间的关系，其中弹性应变可以忽略不计。
The Levi–Mises equations (also called flow rules) describe the relationship between stress and strain for an ideal plastic solid where the elastic strains are negligible.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 矿脉坐标 ( z , r , θ ) {\displaystyle (z,r,\theta )} 或 Haigh–Westergaard 坐标 ( xi , ρ , θ ) {\displaystyle (\xi ,\rho ,\theta )} 。是一组张量不变量，跨越实数、对称、二阶、3 维张量空间，并且与主应力空间同构。这个右手正交坐标系是为了纪念德国科学家 Walter Lode 博士而命名的，因为他在 1926 年撰写的开创性论文描述了中主应力对金属塑性的影响。
Lode coordinates ( z , r , θ ) {\displaystyle (z,r,\theta )} or Haigh–Westergaard coordinates ( ξ , ρ , θ ) {\displaystyle (\xi ,\rho ,\theta )} . are a set of tensor invariants that span the space of real, symmetric, second-order, 3-dimensional tensors and are isomorphic with respect to principal stress space. This right-handed orthogonal coordinate system is named in honor of the German scientist Dr. Walter Lode because of his seminal paper written in 1926 describing the effect of the middle principal stress on metal plasticity.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 材料失效理论是材料科学和固体力学的一个跨学科领域，试图预测固体材料在外部载荷作用下失效的条件。材料的失效通常分为脆性失效（断裂）或延性失效（屈服）。根据条件（例如温度、应力状态、加载速率），大多数材料可能会以脆性或延性方式或两者兼而有之。然而，对于大多数实际情况，材料可以分为脆性材料或延性材料。用数学术语来说，失效理论以对特定材料有效的各种失效准则的形式表达。失效准则是应力或应变空间中的函数，它将“失效”状态与“未失效”状态分开。
Material failure theory is an interdisciplinary field of materials science and solid mechanics which attempts to predict the conditions under which solid materials fail under the action of external loads. The failure of a material is usually classified into brittle failure (fracture) or ductile failure (yield). Depending on the conditions (such as temperature, state of stress, loading rate) most materials can fail in a brittle or ductile manner or both. However, for most practical situations, a material may be classified as either brittle or ductile. In mathematical terms, failure theory is expressed in the form of various failure criteria which are valid for specific materials. Failure criteria are functions in stress or strain space which separate "failed" states from "unfailed" states.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在材料科学和固体力学中，泊松比（符号：ν (nu)）是泊松效应的度量，即材料在垂直于特定载荷方向的方向上的变形（膨胀或收缩）。泊松比的值为横向应变与轴向应变之比的负值。对于这些变化较小的值，ν 是横向伸长量除以轴向压缩量。大多数材料的泊松比值在 0.0 到 0.5 之间。对于橡胶等软材料，其体积模量远高于剪切模量，泊松比接近 0.5。对于开孔聚合物泡沫，泊松比接近于零，因为孔在压缩时容易塌陷。许多典型固体的泊松比在 0.2 到 0.3 范围内。
In materials science and solid mechanics, Poisson's ratio (symbol: ν (nu)) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading. The value of Poisson's ratio is the negative of the ratio of transverse strain to axial strain. For small values of these changes, ν is the amount of transversal elongation divided by the amount of axial compression. Most materials have Poisson's ratio values ranging between 0.0 and 0.5. For soft materials, such as rubber, where the bulk modulus is much higher than the shear modulus, Poisson's ratio is near 0.5. For open-cell polymer foams, Poisson's ratio is near zero, since the cells tend to collapse in compression. Many typical solids have Poisson's ratios in the range of 0.2 to 0.3.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
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