📚 Year 12 SQA Engineering: Vocabulary & Terminology Quick Guide | 12 年级 SQA 工程：词汇术语速记指南
Mastering engineering vocabulary is essential for success in the Year 12 SQA Engineering course. This guide collects key terms from mechanics, electronics, manufacturing, thermodynamics, and more, pairing them with simple memory tricks. Using these definitions accurately will strengthen your written answers, design justifications, and practical investigations.
掌握工程词汇对在12年级 SQA 工程课程中取得成功至关重要。本指南汇集了力学、电子学、制造工艺、热力学等主题的关键术语，并配套简单的记忆技巧。准确使用这些定义将强化你的书面答案、设计论证以及实践探究。
1. Mechanics and Materials | 力学与材料
The mechanics and materials section introduces stress, strain, material properties and force analysis. These concepts underpin structural design and failure prediction.
力学与材料部分引入应力、应变、材料属性和受力分析。这些概念是结构设计和失效预测的基础。
σ = F / A
ies how intensely a material resists an external load. Unit: pascal (Pa) or N/m². Remember "Stress = Squeeze".
应力（σ）是单位面积上的内力。它量化了材料抵抗外部载荷的强度。单位：帕斯卡（Pa）或 N/m²。助记：“应力就像挤压”。
₀. It tells you how much a material stretches or compresses relative to its original size.
应变（ε）是长度变化量与原始长度的无量纲比值：ε = ΔL / L₀。它告诉你材料相对于原始尺寸拉伸或压缩了多少。
E = σ / ε
Young's modulus (E) measures stiffness and is constant in the elastic region. A high E means the material is difficult to stretch. Link it to "Elastic slope".
杨氏模量（E）度量刚度，在弹性区域内为常数。高的 E 意味着材料难以拉伸。可联想“弹性斜率”。
mation begins. Beyond this point the material will not return to its original shape. Think "yield = permanent bend".
屈服强度是塑性变形开始时的应力。超过此点，材料无法回复原状。可记“屈服即永久弯曲”。
Toughness is the total energy absorbed per unit volume before fracture. Hardness is resistance to surface indentation. A tough material withstands impact; a hard material resists scratching.
韧性是断裂前单位体积吸收的总能量。硬度是抵抗表面压痕的能力。韧性材料耐冲击；硬度材料耐刮擦。
2. Electrical Principles | 电气原理
Electrical terms describe charge, potential difference, current, and power. These are central to circuits, sensors, and electronic control systems in engineering.
电气术语描述电荷、电位差、电流和功率。它们是工程中电路、传感器和电子控制系统的核心。
Voltage (V) is the electrical potential difference that drives current. It is measured in volts (V). Think of voltage as "electrical pressure".
电压（V）是驱动电流的电位差。单位是伏特（V）。可将电压视为“电压力”。
w of electric charge, measured in amperes (A). I = Q / t, where Q is charge and t is time.
电流（I）是电荷流动的速率，单位是安培（A）。I = Q / t，其中 Q 为电荷，t 为时间。
V = I × R
Ohm's law states that voltage equals current multiplied by resistance. Resistance (R) opposes flow and is measured in ohms (Ω).
欧姆定律指出电压等于电流乘以电阻。电阻（R）阻碍电流流动，单位是欧姆（Ω）。
ergy transfer: P = V × I. Unit: watt (W). In a resistor, heat dissipation follows P = I²R.
功率（P）是能量传递的速率：P = V × I。单位是瓦特（W）。在电阻中，热耗散遵循 P = I²R。
/ V, measured in farads (F). Capacitors smooth voltage fluctuations in rectifier circuits.
电容（C）是储存电荷的能力，C = Q / V，单位是法拉（F）。电容器用于平滑整流电路中的电压波动。
3. Manufacturing Processes | 制造工艺
Manufacturing terminology covers shaping, joining, and finishing techniques. Recognising process capabilities helps you select the right method for a given product.
制造术语涵盖成形、连接和表面处理技术。识别工艺能力有助于为给定产品选择正确的方法。
Casting involves pouring molten metal into a mould. Sand casting is economical for large parts; die casting offers high precision for mass production.
铸造涉及将熔融金属浇入模具。砂型铸造对于大型零件经济实惠；压铸为大规模生产提供高精度。
using compressive forces, often while hot. It improves grain structure and strength. Think "forge = hammer and shape".
锻造利用压缩力（通常加热）使金属成形。它改善晶粒结构并提高强度。可联想“锻造 = 锤击成形”。
Welding joins materials by melting and fusing them, usually with a filler. Common processes: MIG, TIG, and arc welding.
焊接通过熔化并融合材料来进行连接，通常使用填充料。常见工艺：MIG 焊、TIG 焊和电弧焊。
Machining removes material using cutting tools (turning, milling, drilling). It produces tight tolerances but generates waste chips.
机械加工使用切削刀具（车削、铣削、钻削）去除材料。它能实现紧公差但会产生切屑废料。
Additive manufacturing (3D printing) builds parts layer by layer. It is ideal for complex geometries and prototyping but may be slower for high volumes.
增材制造（3D 打印）逐层构建零件。它非常适合复杂几何形状和原型制作，但在大批量生产时可能较慢。
4. Engineering Drawings & CAD | 工程图纸与CAD
Engineering drawing terms describe projection methods, dimensioning, and tolerancing. Clear interpretation of drawings is vital for manufacturing and inspection.
工程制图术语描述投影方法、尺寸标注和公差。清晰解读图纸对于制造和检验至关重要。
Orthographic projection shows a 3D object through multiple 2D views (front, top, side). Always align views using standard conventions.
正投影通过多个二维视图（前视图、俯视图、侧视图）展示三维物体。务必按照标准惯例对齐视图。
Isometric drawing presents a 3D pictorial view where axes are 120° apart. It gives a realistic feel without perspective distortion.
等轴测图以120°轴线呈现三维立体图。它提供真实感而无透视变形。
variation. A dimension of 50 ± 0.1 mm means the part must be between 49.9 mm and 50.1 mm.
尺寸表示大小；公差指定允许的变动量。尺寸 50 ± 0.1 mm 表示零件必须在 49.9 mm 至 50.1 mm 之间。
GD&T (Geometric Dimensioning and Tolerancing) uses symbols to control form, orientation, and position. It reduces ambiguity compared to plus/minus tolerances alone.
几何尺寸与公差（GD&T）使用符号来控制形状、方向和位置。与仅使用正负公差相比，它能减少歧义。
CAD (Computer-Aided Design) software creates precise digital models. CAM (Computer-Aided Manufacturing) converts those models into machine toolpaths.
CAD（计算机辅助设计）软件创建精确的数字模型。CAM（计算机辅助制造）将这些模型转化为机床路径。
5. Thermodynamics | 热力学
Thermodynamics deals with heat, work, and energy conversion. These terms explain engine cycles, refrigeration, and energy efficiency.
热力学涉及热、功和能量转换。这些术语用于解释发动机循环、制冷和能效。
Internal energy (U) is the total energy stored within a system due to molecular motion and bonding. It changes when heat or work is transferred.
内能（U）是由于分子运动和键合而储存在系统内的总能量。当传递热或功时它会变化。
ΔU = Q − W
The First Law of Thermodynamics: the change in internal energy equals heat added (Q) minus work done by the system (W). Think "energy is conserved".
热力学第一定律：内能的变化等于吸收的热量（Q）减去系统对外做的功（W）。可记作“能量守恒”。
Enthalpy (H) is defined as H = U + pV. It is useful for flow processes and constant‑pressure reactions. Remember "H for heat content".
焓（H）定义为 H = U + pV。它对于流动过程和等压反应很有用。助记：“H 代表热含量”。
Entropy (S) measures disorder or randomness. The Second Law states that total entropy never decreases in an isolated system.
熵（S）衡量无序度或随机性。第二定律指出孤立系统的总熵永不减少。
emperature of 1 kg of a substance by 1 K: Q = m c ΔT. Water has a high c (≈ 4.18 kJ/kg·K).
比热容（c）是使 1 kg 物质温度升高 1 K 所需的能量：Q = m c ΔT。水具有高 c 值（约 4.18 kJ/kg·K）。
6. Fluid Mechanics | 流体力学
Fluid mechanics covers fluids at rest and in motion. Key concepts include pressure, flow regimes, and energy conservation in pipes and channels.
流体力学涵盖静止和运动中的流体。关键概念包括压力、流态以及管道和渠道中的能量守恒。
ρgh, where ρ is density, g is gravity, and h is depth. It acts equally in all directions.
静止流体中的压力遵循 p = ρgh，其中 ρ 为密度，g 为重力加速度，h 为深度。压力在所有方向均等作用。
Re = ρvD / μ
Reynolds number (Re) predicts flow type. Re < 2000 indicates laminar flow; Re > 4000 typically turbulent. Here v is velocity, D is diameter, and μ is dynamic viscosity.
雷诺数（Re）预测流动类型。Re < 2000 为层流；Re > 4000 通常为湍流。这里 v 为流速，D 为直径，μ 为动力粘度。
Viscosity is a fluid' ce to flow. High-viscosity fluids (e.g. honey) flow slowly. Kinematic viscosity ν = μ / ρ.
粘度是流体内部对流动的阻力。高粘度流体（如蜂蜜）流动缓慢。运动粘度 ν = μ / ρ。
p + ½ρv² + ρgh = constant
Bernoulli's equation expresses energy conservation along a streamline. It links pressure energy, kinetic energy per unit volume, and potential energy.
伯努利方程表达了沿流线的能量守恒。它将压力能、单位体积的动能和势能联系起来。
Laminar flow is smooth and ordered; turbulent flow is chaotic with eddies. The transition depends on Re and surface roughness.
层流平滑有序；湍流混乱并带有涡旋。转变取决于 Re 和表面粗糙度。
7. Control Systems | 控制系统
Control systems terminology describes how inputs, feedback, and controllers regulate engineering processes. These appear in robotics, automation, and process control.
控制系统术语描述输入、反馈和控制器如何调节工程过程。这些术语出现在机器人、自动化和过程控制中。
Open-loop control sends a command without checking the output. It is simple but cannot correct for disturbances. Example: a toaster with a fixed timer.
开环控制发送命令而不检查输出。它简单但无法纠正干扰。例：使用固定定时器的烤面包机。
Closed-loop (feedback) control continuously compares actual output to the desired setpoint and adjusts input accordingly. The feedback loop improves accuracy.
闭环（反馈）控制持续比较实际输出与期望设定值，并相应调整输入。反馈回路提高了精度。
A transfer function represents the input-output relationship of a system in the Laplace domain. It is the cornerstone of frequency-domain analysis.
传递函数表示拉普拉斯域中系统的输入-输出关系。它是频域分析的基石。
PID controller stands for Proportional, Integral, Derivative. P responds to present error, I to past errors, D to predicted future error. Tuning each gain optimises response.
PID 控制器代表比例、积分、微分。P 响应当前误差，I 响应过去误差，D 响应预测的未来误差。调整每个增益可优化响应。
A block diagram uses labelled blocks and arrows to show signal flow and function. It helps visualise complex control architectures.
框图使用带标签的方框和箭头展示信号流和功能。它有助于将复杂的控制架构可视化。
8. Engineering Materials | 工程材料
Materials classification and properties help engineers choose the right material for strength, weight, corrosion resistance, and cost. Key groups include metals, polymers, ceramics, and composites.
材料分类和属性帮助工程师在强度、重量、耐腐蚀性和成本方面选择合适材料。主要类别包括金属、聚合物、陶瓷和复合材料。
Ferrous metals contain iron (e.g. steel, cast iron). They are magnetic and prone to rust but offer high strength and low cost.
黑色金属含铁（如钢、铸铁）。
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