IGCSE CAIE Engineering: Case Study Practical Exercises | IGCSE CAIE 工程：案例分析实战演练

📚 IGCSE CAIE Engineering: Case Study Practical Exercises | IGCSE CAIE 工程：案例分析实战演练

Case study questions are a central feature of the Cambridge IGCSE Engineering exam. They test your ability to apply design, materials, mechanics, electronics, manufacturing and sustainability ideas to a realistic engineering problem. This revision guide shows you how to work through a case study step by step, with bilingual explanations and worked calculations.

案例分析题是剑桥 IGCSE 工程考试的核心组成部分。它们考查你将设计、材料、力学、电子、制造和可持续性理念应用于现实工程问题的能力。本复习指南用中英双语逐步展示如何完成一个案例分析，并提供计算范例。

1. Understanding the Case Study Command Words | 理解案例分析指令词

Case study questions in CAIE IGCSE Engineering often use command words such as ‘state’, ‘describe’, ‘explain’, ‘calculate’ and ‘evaluate’. You must read the prompt carefully and match the depth of your answer to the command word.

CAIE IGCSE 工程中的案例分析题常使用“陈述”“描述”“解释”“计算”和“评估”等指令词。你必须仔细阅读题干，并根据指令词决定答案的详细程度。

For example, ‘state’ requires a one-word or short factual answer, while ‘explain’ requires a cause-and-effect chain. If a question asks you to ‘evaluate’ a design, you should give advantages and disadvantages and then make a supported judgement.

例如，“陈述”要求一个词或简短的事实回答，而“解释”要求因果链条。如果题目要求“评估”某个设计，你应给出优点和缺点，然后作出有依据的判断。

Before you write, underline the command word and the context. This prevents the common mistake of describing when the question asks for evaluation, or giving general textbook knowledge without applying it to the case.

作答前，圈出指令词和题干背景。这样可以防止常见错误：题目要求评估时却在描述，或只给出教科书知识而未能结合实际案例。

2. The Design Process: From Brief to Specification | 设计流程：从任务书到规格说明

A typical case study begins with a design brief describing a problem, such as ‘design a device to lift boxes in a warehouse’. Your first task is to turn this brief into measurable design specifications.

典型的案例研究从描述问题的设计任务书开始，例如“设计一种在仓库中提升箱子的装置”。你的第一个任务是把任务书转化为可测量的设计规格。

Strong specifications include function, target user, maximum load, speed, size limits, safety requirements, cost and environmental constraints. Avoid vague terms such as ‘strong’ or ‘cheap’ unless you give numerical values.

良好的规格包括功能、目标用户、最大载荷、速度、尺寸限制、安全要求、成本和环境约束。除非给出数值，否则避免使用“坚固”或“便宜”等模糊词语。

Example specification: maximum load = 500 N, lifting height ≥ 1.2 m, operating cost ≤ £0.05 per cycle, noise ≤ 70 dB.

示例规格：最大载荷 = 500 N，提升高度 ≥ 1.2 m，运行成本 ≤ 每次循环 £0.05，噪声 ≤ 70 dB。

You can then use this specification to compare different design concepts. A motor-driven pulley system might meet the speed requirement, but a manual hydraulic lift might be better if the warehouse has no electrical supply.

然后你可以使用该规格来比较不同设计方案。电动滑轮系统可能满足速度要求，但如果仓库没有电源，手动液压升降机可能更好。

3. Materials Selection Case Study: Bridge Structure | 材料选择案例：桥梁结构

Imagine a lightweight footbridge made from a truss. You must choose between low-carbon steel, aluminium alloy and timber. Each material has different density, tensile strength, stiffness, corrosion resistance and cost.

想象一座由桁架构成的轻型人行桥。你必须在低碳钢、铝合金和木材之间做出选择。每种材料具有不同的密度、抗拉强度、刚度、耐腐蚀性和成本。

Low-carbon steel has high strength and low cost but is dense and rusts without coating. Aluminium alloy is lighter and corrosion-resistant but more expensive and more difficult to weld. Timber is renewable and cheap but weaker and vulnerable to rot.

低碳钢强度高、成本低，但密度大，无涂层时会生锈。铝合金更轻且耐腐蚀，但更昂贵且更难焊接。木材可再生且便宜，但强度较低且易腐烂。

Use a material properties table to justify a decision. In a short answer, always link the property to the specific function: ‘aluminium is chosen for the deck because its low density reduces the dead load on the piers’.

使用材料特性表来证明决策。在简答题中，始终将性质与具体功能联系起来：“面板选择铝材，因为其低密度减小了桥墩上的恒载。”