📚 Year 12 WJEC Engineering: Quick Vocabulary Memorization Guide | 词汇术语速记指南
Mastering technical vocabulary is the first step toward excelling in WJEC Year 12 Engineering. Without a solid grasp of key terms, even simple exam questions can become confusing. This bilingual guide presents essential terminology in logically grouped sections, with clear explanations and helpful memory hooks to accelerate your learning and boost your confidence.
掌握专业术语是在 WJEC 12 年级工程学中脱颖而出的第一步。如果没有扎实的关键术语基础，即使简单的考题也可能变得令人困惑。这份双语指南将核心术语按逻辑分组，提供清晰的解释和实用的记忆方法，帮助你加快学习速度、增强信心。
1. Fundamental Quantities and Derived Units | 基本物理量与导出单位
Any engineering analysis starts with base quantities. In the SI system, mass (m) is measured in kilograms (kg), length (l) in metres (m), time (t) in seconds (s), and electric current (I) in amperes (A).
任何工程分析都从基本量开始。在国际单位制中，质量（m）以千克（kg）为单位，长度（l）以米（m）为单位，时间（t）以秒（s）为单位，电流（I）以安培（A）为单位。
Derived units are built from these bases. Force is measured in newtons, where 1 N = 1 kg·m/s². Pressure uses the pascal (1 Pa = 1 N/m²), and energy or work is expressed in joules (1 J = 1 N·m).
导出单位由这些基本单位组合而成。力以牛顿为单位，1 N = 1 kg·m/s²。压力使用帕斯卡（1 Pa = 1 N/m²），能量或功以焦耳表示（1 J = 1 N·m）。
When dealing with very large or very small numbers, standard prefixes simplify communication: kilo (k, 10³), mega (M, 10⁶), milli (m, 10⁻³), and micro (µ, 10⁻⁶). For example, a force of 5000 N can be written as 5 kN.
处理极大或极小的数值时，标准前缀可以简化沟通：千（k，10³）、兆（M，10⁶）、毫（m，10⁻³）和微（µ，10⁻⁶）。例如，5000 N 的力可以写作 5 kN。
2. Mechanics: Forces, Moments and Equilibrium | 力学：力、力矩与平衡
A force is a push or pull that can cause an object to accelerate. It is described by magnitudes, direction and point of application. Newton’s second law states that the net force equals mass times acceleration: Fnet = m × a.
力是一种能够使物体加速的推或拉。它由大小、方向和作用点来描述。牛顿第二定律指出，合外力等于质量乘以加速度：F合 = m × a。
The moment of a force about a pivot is the turning effect, calculated as M = F × d, where d is the perpendicular distance from the line of action of the force to the pivot. Moments are measured in newton‑metres (N·m).
力对支点的力矩是转动效应，计算公式为 M = F × d，其中 d 是力的作用线到支点的垂直距离。力矩的单位是牛顿·米（N·m）。
A system is in static equilibrium when both the sum of all forces and the sum of all moments are zero. The principle of moments states that for a balanced lever, the sum of clockwise moments equals the sum of anticlockwise moments.
当所有力的总和与所有力矩的总和均为零时，系统处于静力平衡状态。力矩原理指出，对于一根平衡的杠杆，顺时针力矩之和等于逆时针力矩之和。
ΣF = 0 and ΣM = 0
3. Stress, Strain and Young’s Modulus | 应力、应变与杨氏模量
Stress (σ) is the internal force per unit area within a material when an external load is applied. It is calculated as σ = F / A and measured in pascals (Pa). Direct stress can be tensile (pulling) or compressive (pushing).
应力（σ） 是在施加外部载荷时，材料内部单位面积上的力。计算公式为 σ = F / A，单位是帕斯卡（Pa）。正应力可以是拉伸应力或压缩应力。
Strain (ε) describes the deformation of a material relative to its original dimension. Tensile strain is the change in length divided by the original length: ε = Δl / l₀. Strain is a ratio and has no units.
应变（ε） 描述材料相对于原始尺寸的变形。拉伸应变是长度变化量除以原始长度：ε = Δl / l₀。应变是一个比率，没有单位。
Young’s modulus (E) is a measure of stiffness, defined as the ratio of stress to strain in the elastic region: E = σ / ε. A steep stress‑strain graph indicates a high Young’s modulus, meaning the material resists deformation under load.
杨氏模量（E） 是刚度的度量，定义为弹性区域内应力与应变的比值：E = σ / ε。应力‑应变曲线陡峭表明杨氏模量高，意味着材料在载荷下抵抗变形能力强。
4. Material Properties and Testing | 材料性质与测试
Strength refers to the ability of a material to withstand an applied load without failure. Tensile strength is the maximum stress a material can endure while being stretched before necking or breaking.
强度指材料承受外加载荷而不失效的能力。抗拉强度是材料在被拉伸时，在颈缩或断裂前所能承受的最大应力。
Hardness measures a material’s resistance to indentation or scratching. Typical tests include Brinell, Vickers and Rockwell methods. A hard material like hardened steel resists surface wear but may be brittle.
硬度衡量材料抵抗压痕或划痕的能力。常用测试包括布氏、维氏和洛氏方法。淬火钢等高硬度材料抗表面磨损，但可能较脆。
Ductility is the capacity to be drawn into a wire or plastically deformed without breaking. Copper is highly ductile. In contrast, brittleness describes materials that fracture with little plastic deformation, such as cast iron.
延性是将材料拉成丝状或发生塑性变形而不破裂的能力。铜具有高延展性。相反，脆性描述的是几乎没有塑性变形就会断裂的材料，例如铸铁。
Toughness is the ability to absorb energy up to fracture, combining strength and ductility. The Charpy impact test measures toughness by recording the energy absorbed by a notched specimen.
韧性是在断裂前吸收能量的能力，是强度和延性的结合。夏比冲击试验通过记录缺口试样吸收的能量来衡量韧性。
5. Manufacturing Processes | 制造工艺
Casting involves pouring molten metal into a mould cavity where it solidifies. Sand casting is used for large components, while die casting suits high‑volume production of non‑ferrous parts. The mould design must include a riser to compensate for shrinkage.
铸造是将熔融金属倒入模腔中使其凝固。砂型铸造用于大型部件，而压铸适用于有色金属零件的大批量生产。模具设计必须包含冒口以补偿收缩。
Forging shapes metal using compressive forces, often applied by a hammer or press. The process refines the grain structure, improving strength and toughness. Drop forging is common for automotive connecting rods.
锻造利用压力成形金属，通常由锤或压力机施加。该工艺细化晶粒结构，提高强度和韧性。落锤锻造常用于汽车连杆。
Machining removes material from a workpiece using a cutting tool. Turning produces cylindrical shapes on a lathe, while milling uses a rotating multi‑point cutter to form flat surfaces and slots. The term CNC (Computer Numerical Control) refers to automated control of machining tools via programmed commands.
机械加工使用切削刀具从工件上去除材料。车削在车床上加工出圆柱形状，铣削则利用旋转的多刃刀具成形平面和槽。CNC（计算机数控）指通过编程指令对加工刀具进行自动化控制。
Welding joins materials, typically metals, by melting the interface and allowing it to fuse. Common techniques include MIG, TIG and spot welding. The weld bead is the deposited filler metal after solidification.
焊接通过熔化接合面并使其熔合来连接材料，通常是金属。常见技术包括 MIG、TIG 和点焊。焊道是凝固后沉积的填充金属。
6. Engineering Drawings, Tolerances and Fits | 工程图纸、公差与配合
Engineering drawings communicate design intent unambiguously. Orthographic projection uses multiple 2D views (front, top, side) to represent a 3D object. Isometric projection offers a pictorial view where three faces are visible at once.
工程图纸明确传达设计意图。正交投影使用多个二维视图（前、俯、侧）来表示三维物体。等轴测投影提供一幅三面同时可见的立体图。
Tolerance specifies the permissible limit of variation in a physical dimension. A dimension of 50 ±0.1 mm means the part is acceptable if its size lies between 49.9 mm and 50.1 mm. Tolerances are essential for interchangeable parts.
公差规定了物理尺寸的允许变动范围。尺寸 50 ±0.1 mm 意味着只要零件尺寸在 49.9 mm 至 50.1 mm 之间即可接受。公差对于互换性零件至关重要。
Fit describes the relationship between mating parts before assembly. A clearance fit always leaves a gap (e.g., a shaft rotating inside a bearing), while an interference fit requires force to assemble because the shaft is slightly larger than the hole.
配合描述装配前配合零件之间的关系。间隙配合始终留有间隙（例如轴在轴承中旋转），而过盈配合则需要外力装配，因为轴径略大于孔径。
Surface roughness quantifies the texture of a machined surface. The parameter Ra (arithmetical mean deviation) is commonly used, with a smaller Ra value indicating a smoother finish, typically achieved by grinding or polishing.
表面粗糙度量化加工表面的纹理。Ra（算术平均偏差）参数常用，Ra 值越小表示表面越光滑，通常通过磨削或抛光实现。
7. Electrical Principles | 电学原理
Current (I) is the rate of flow of electric charge, measured in amperes. In a metallic conductor, it is the drift of free electrons. Conventional current flows from positive to negative, opposite to electron flow.
电流（I）是电荷流动的速率，以安培为单位。在金属导体中，它是自由电子的漂移。传统电流方向为由正到负，与电子流动方向相反。
Voltage (V) or potential difference is the energy transferred per unit charge. It drives current around a circuit and is measured in volts. Ohm’s law relates voltage, current and resistance: V = I × R, valid for ohmic conductors at constant temperature.
电压（V）或电位差是每单位电荷传递的能量。它驱动电流在电路中流动，以伏特为单位。欧姆定律将电压、电流和电阻关联起来：V = I × R，适用于恒温下的欧姆导体。
Resistance (R) opposes current flow, measured in ohms (Ω). It depends on the material’s resistivity (ρ), length (l) and cross‑sectional area (A): R = ρ × l / A. Resistors in series add directly, while parallel resistors follow 1/Rtotal = 1/R₁ + 1/R₂ + …
电阻（R）阻碍电流流动，单位为欧姆（Ω）。它取决于材料的电阻率（ρ）、长度（l）和截面积（A）：R = ρ × l / A。串联电阻直接相加，并联电阻遵循 1/R总 = 1/R₁ + 1/R₂ + …
Electrical power (P) is the rate at which electrical energy is transferred, given by P = V × I or P = I² × R. A resistor dissipates energy as heat; the power rating indicates how much it can handle without damage.
电功率（P）是电能传递的速率，计算公式为 P = V × I 或 P = I² × R。电阻器以热的形式耗散能量；额定功率表示其在不受损情况下能承受的功率。
8. Energy, Work, Power and Efficiency | 能量、功、功率与效率
Work (W) is done when a force moves its point of application. In linear motion, W = F × d, where d is the displacement in the direction of the force. Work and energy both use joules (J).
当力使其作用点移动时就做了功（W）。在直线运动中，W = F × d，其中 d 是沿力方向的位移。功和能量都用焦耳（J）。
Power (P) is the rate of doing work, P = W / t or in mechanical terms P = F × v (force × velocity). The unit is the watt (W), where 1 W = 1 J/s. Engineering machines are often rated in kilowatts.
功率（P）是做功的速率，P = W / t，或者从机械角度表达为 P = F × v（力 × 速度）。单位是瓦特（W），1 W = 1 J/s。工程机械常以千瓦标定。
Gravitational potential energy is Ep = m × g × h. Kinetic energy is Ek = ½ × m × v². In a closed system, total mechanical energy is conserved when only conservative forces act, although friction converts some energy into heat.
重力势能为 Ep = m × g × h。动能为 Ek = ½ × m × v²。在保守力作用的封闭系统中，总机械能守恒，但摩擦会将部分能量转化为热能。
Efficiency (η) compares useful output power to total input power: η = (useful power out / total power in) × 100%. No practical system is 100% efficient due to losses from friction, heat and sound.
效率（η）是将有用输出功率与总输入功率作比较：η =（有用输出功率 / 总输入功率）× 100%。由于摩擦、热和声音造成的损耗，实际系统无法达到 100% 的效率。
9. Health, Safety and Risk Assessment | 健康、安全与风险评估
Risk assessment is the systematic process of identifying hazards, evaluating the likelihood and severity of harm, and implementing control measures. In a workshop, hazards might include rotating machinery, sharp edges, noise and hazardous substances.
风险评估是识别危险、评估危害发生的可能性和严重程度并实施控制措施的系统过程。在车间中，危险可能包括旋转机械、锋利边缘、噪音和有害物质。
The hierarchy of control ranks precautions from most to least effective: elimination, substitution, engineering controls, administrative controls and finally PPE (Personal Protective Equipment). PPE such as safety glasses, gloves and steel‑toe boots is always the last line of defence.
控制层级将预防措施按有效性从高到低排列：消除、替代、工程控制、管理控制，最后是PPE（个人防护装备）。PPE 如安全眼镜、手套和钢头靴始终是最后的防线。
COSHH (Control of Substances Hazardous to Health) regulations require employers to control exposure to dangerous chemicals, dusts and fumes. A Safety Data Sheet (SDS) provides detailed information about a substance’s hazards and handling procedures.
COSHH（有害健康物质控制）条例要求雇主控制接触危险化学品、粉尘和烟气的风险。安全数据表（SDS） 提供有关物质危害和处理程序的详细信息。
10. CAD/CAM and CNC Terminology | CAD/CAM 与 CNC 术语
CAD (Computer-Aided Design) software is used to create precision 2D or 3D models. Parametric modelling allows dimensions and relationships to be updated automatically, saving time in iterative design.
CAD（计算机辅助设计）软件用于创建精确的二维或三维模型。参数化建模允许尺寸和关系自动更新，在迭代设计中节省时间。
CAM (Computer-Aided Manufacturing) converts CAD models into machine instructions, typically G‑code, which controls tool paths, speeds and feeds. The CAM process generates a toolpath strategy, such as profile cutting or pocket milling.
CAM（计算机辅助制造）将 CAD 模型转化为机器指令，通常为G 代码，用于控制刀具路径、速度和进给。CAM 过程生成刀具路径策略，如轮廓切割或型腔铣削。
CNC routers and milling machines can perform multiple operations automatically. The work coordinate system (WCS) defines the origin point from which all tool positions are referenced. Setting the WCS accurately is vital for dimensional accuracy.
CNC 雕刻机和铣床可自动执行多种操作。工件坐标系（WCS）定义了一个原点，所有刀具位置均以此为基准。精确设置 WCS 对于尺寸精度至关重要。
FEA (Finite Element Analysis) is a simulation tool used within CAD to predict how a product reacts to real‑world forces, vibration and heat. It identifies stress concentrations and potential failure points before prototyping.
FEA（有限元分析）是 CAD 中的仿真工具，用于预测产品在真实力、振动和热作用下的反应。它在原型制作前识别应力集中和潜在故障点。
11. Fluid and Thermal Systems | 流体与热力学系统
Pressure (p) in a fluid acts equally in all directions. In a static liquid, pressure increases with depth following p = ρ × g × h. Hydraulic systems use Pascal’s principle to multiply force: a small force applied on a small piston creates a large force on a larger piston.
流体中的压力（p）在所有方向上作用相等。在静止液体中，压力随深度增加，遵循 p = ρ × g × h。液压系统利用帕斯卡原理增大力：施加在小活塞上的小力在大活塞上产生较大的力。
Flow rate (Q) is the volume of fluid passing a point per unit time, often in m³/s. The continuity equation for an incompressible fluid is A₁ × v₁ = A₂ × v₂, meaning velocity increases as the cross‑sectional area decreases.
流量（Q）是单位时间内流过某点的流体体积，常用 m³/s 表示。不可压缩流体的连续性方程为 A₁ × v₁ = A₂ × v₂，即截面积减小时流速增加。
Bernoulli’s principle states that an increase in fluid speed occurs simultaneously with a decrease in pressure or potential energy. It explains lift on an aircraft wing and the operation of a venturi meter.
伯努利原理指出，流体速度增加的同时压力或势能下降。它解释了飞机机翼的升力和文丘里流量计的工作原理。
In thermodynamics, temperature is a measure of internal energy. Heat transfer occurs via conduction (through solids), convection (through fluids) and radiation (through electromagnetic waves). The thermal conductivity (k) of a material dictates how quickly heat flows through it.
在热力学中，温度是内能的度量。传热通过传导（固体）、对流（流体）和辐射（电磁波）进行。材料的导热系数（k）决定了热量流过它的速度。
12. Control Systems and Sensors | 控制系统与传感器
An open‑loop system operates without feedback, executing a predefined sequence regardless of the actual output. A simple timer‑controlled toaster is an open‑loop device, as it does not measure browning.
开环系统在没有反馈的情况下运行，根据预定义的顺序执行，而不考虑实际输出。简单的定时控制烤面包机就是一个开环设备，因为它不测量焦黄程度。
A closed‑loop system uses feedback from a sensor to compare the actual output with the desired set point. The difference, called the error signal, drives the controller to make corrections. Cruise control in a car is a typical example.
闭环系统利用传感器的反馈，将实际输出与期望设定值进行比较。这个差值称为误差信号，驱动控制器进行修正。汽车的巡航控制就是一个典型例子。
Common sensors include thermocouples (temperature), strain gauges (force or deformation), LVDTs (linear displacement) and ultrasonic sensors (distance). Each sensor produces an electrical signal that can be conditioned and read by a microcontroller.
常见传感器包括热电偶（温度）、应变片（力或变形）、LVDT（线性位移）和超声波传感器（距离）。每个传感器都会产生一个电信号，经过调理后可被微控制器读取。
An actuator converts a control signal into physical movement. Examples are DC motors, stepper motors, solenoids and hydraulic cylinders. In a mechatronic system, the microcontroller processes sensor data and commands the actuator to achieve precise motion.
执行器将控制信号转化为物理运动。例子包括直流电机、步进电机、电磁阀和液压缸。在机电一体化系统中，微控制器处理传感器数据并指令执行器实现精确运动。
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