Year 12 CAIE Engineering: Core Knowledge Review | Year 12 CAIE 工程：核心知识点梳理

📚 Year 12 CAIE Engineering: Core Knowledge Review | Year 12 CAIE 工程：核心知识点梳理

The Year 12 CAIE Engineering syllabus introduces students to the fundamental principles of mechanical, electrical, thermal and materials engineering. This article provides a structured recap of the core knowledge areas, linking key concepts, essential equations and practical applications to help you consolidate your understanding for the AS examinations.

Year 12 CAIE 工程教学大纲向学生介绍机械、电气、热学和材料工程的基本原理。本文对核心知识领域进行了系统的梳理，将关键概念、基本方程和实际应用联系起来，以帮助你巩固理解，为 AS 考试做好准备。

1. Forces and Equilibrium | 力与平衡

Forces are vector quantities that can be resolved into perpendicular components. A body is in static equilibrium when the net force in any direction is zero and the net moment about any point is zero. The principle of moments states that for a body in rotational equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.

力是矢量，可以分解为相互垂直的分量。当一个物体在所有方向上的合力都为零，且对任意点的合力矩也为零时，该物体处于静力平衡状态。力矩原理指出，对于处于转动平衡的物体，顺时针力矩之和等于逆时针力矩之和。

The moment of a force about a point is calculated as the product of the force and the perpendicular distance from the point to the line of action of the force (M = F × d). In many structures, support reactions are determined by applying the two equilibrium conditions: ΣF_h = 0, ΣF_v = 0 and ΣM = 0.

力对某点的力矩等于力的大小乘上该点到力作用线的垂直距离 (M = F × d)。在许多结构中，支座反力可以通过应用两个平衡条件来确定：水平合力为零 ΣF_h = 0，竖直合力为零 ΣF_v = 0，以及合力矩为零 ΣM = 0。

2. Stress, Strain and Young Modulus | 应力、应变与杨氏模量

When a material is subjected to an external force, it experiences stress and deformation. Tensile stress (σ) is defined as the force applied per unit cross-sectional area: σ = F / A. The unit is the pascal (Pa). Strain (ε) is the ratio of extension to original length: ε = ΔL / L₀; it has no units.

当材料受到外力作用时，会产生应力和变形。拉应力 (σ) 定义为施加在单位截面积上的力：σ = F / A，单位为帕斯卡 (Pa)。应变 (ε) 是伸长量与原长之比：ε = ΔL / L₀，没有单位。

Young modulus (E) is a measure of the stiffness of a material and is given by E = σ / ε within the linear elastic region. The stress–strain graph for a ductile material shows a linear portion, a yield point, plastic deformation and ultimate tensile strength before fracture. Hooke’s Law

Published by TutorHao | Year 12 工程 Revision Series | aleveler.com

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