KS3 AQA Engineering: Practical Case Study Exercises | KS3 AQA 工程：案例分析实战演练

📚 KS3 AQA Engineering: Practical Case Study Exercises | KS3 AQA 工程：案例分析实战演练

Engineering at KS3 is all about learning to think like an engineer. Through practical case studies, you will investigate real-world design challenges, test materials, assemble systems, and refine your solutions step by step. These exercises mirror the engineering design cycle used by professionals to turn ideas into functional, sustainable products. In this article, we work through a series of hands-on case studies that will strengthen your problem-solving skills and deepen your understanding of structures, electronics, mechanics and sustainable design.

KS3 阶段的工程学核心是学会像工程师一样思考。通过实际案例分析，你将探索真实世界的设计挑战，测试材料，搭建系统，并一步步完善你的解决方案。这些练习模拟了专业人士将创意转化为实用、可持续产品时所遵循的工程设计循环。在本文中，我们将通过一系列动手实操的案例研究，来强化你解决问题的能力，并加深你对结构、电子、机械和可持续设计的理解。

1. Understanding the Engineering Design Cycle | 理解工程设计循环

Every engineering project follows a design cycle that begins with identifying a problem or user need. You research the context, write a design brief, and set measurable criteria and constraints.

每一个工程项目都遵循一个设计循环，首先从识别问题或用户需求开始。你需要调研背景，撰写设计摘要，并设定可量化的评估标准和限制条件。

Next, you generate a range of possible solutions through sketching and brainstorming, often using annotated drawings to communicate ideas quickly.

接下来，你通过草图和头脑风暴生成一系列可能的解决方案，通常会使用带注释的图纸来快速传达想法。

A chosen design is then modelled and prototyped, using materials such as card, clay, or CAD software. Testing the prototype against the original criteria reveals strengths and weaknesses.

然后，选定的设计会被建模并制作成原型，使用的材料可以是卡纸、黏土，或是采用 CAD 软件。将原型对照最初的标准进行测试，能够揭示其优点与不足。

Finally, you evaluate the test results and make iterative improvements. This repeat cycle of testing and refining is at the heart of all engineering disciplines.

最后，你对测试结果进行评估，并做出迭代改进。这种反复的测试与优化循环是所有工程学科的核心。

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2. Case Study 1: The Paper Bridge Challenge | 案例研究 1：纸桥挑战

In this activity, you must design and build a free-spanning bridge from only 10 sheets of A4 paper and a limited amount of adhesive tape. The bridge must span a 30 cm gap and support as much mass as possible at its centre.

在这个活动中，你必须仅用 10 张 A4 纸和有限数量的胶带，设计并建造一座自由跨度的纸桥。桥梁必须跨过一道 30 厘米的间隙，并在桥中心尽可能多地支撑重物。

Begin by researching real bridge forms, such as beam, arch, and truss structures. Many successful paper bridges use a truss design because triangular frames distribute load efficiently and resist bending.

首先研究真实的桥梁形式，例如梁桥、拱桥和桁架桥。许多成功的纸桥采用桁架设计，因为三角形框架能高效分布荷载并抵抗弯曲。

Roll paper into tight tubes to create strong members, and connect them to form triangular patterns. Test your bridge incrementally by adding 100 g masses until failure occurs.

将纸张紧紧卷成管状以制作坚固的构件，再连接起来形成三角形图案。逐步增加 100 克的砝码进行测试，直到桥梁失效。

After failure, analyse where the bridge broke. Was it a joint that slipped, a member that buckled, or a tension tie that snapped? Record your observations and suggest a redesign.

在桥倒塌后，分析断裂的位置。是节点滑脱了，是构件受压弯曲了，还是受拉连杆断裂了？记录观察结果并提出改进设计方案。

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3. Material Selection and Testing | 材料选择与测试

Choosing the right material is critical in any engineering project. Key properties to consider include strength, stiffness, toughness, density, and sustainability.

在任何工程项目中，选择合适的材料都至关重要。需要考虑的关键属性包括强度、刚度、韧性、密度以及可持续性。

Material	Tensile Strength	Density	Typical Use
Cardboard	Medium	Low	Packaging, models
Pine wood	Low-medium	Medium	Furniture, construction
Acrylic	High	Medium	Displays, signs
Aluminium	High	Low	Cans, aircraft parts

Carry out simple tests to experience material behaviour. For example, attach increasing weights to a strip of each material and measure the extension until it breaks to compare tensile strength.

进行简单的测试来体会材料的行为。例如，在每种材料条上逐步增加重物，测量断裂前的伸长量，以比较抗张强度。

When analysing a case study such as a bicycle frame, you would consider aluminium for its low density and high strength, or steel for its toughness and lower cost. The final choice depends on the design priorities.

在分析诸如自行车车架的案例时，你会考虑采用密度低、强度高的铝合金，或者韧性好、成本更低的钢材。最终选择取决于设计的优先考量。

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4. Troubleshooting a Simple Circuit | 简单电路故障排查

In this case study, you are given a simple series circuit containing a battery, a switch, and a lamp that does not light up. You must diagnose the fault using logical steps.

在这个案例研究中，你获得了一个简单的串联电路，包含电池、开关和一个不亮的灯泡。你必须运用逻辑步骤来诊断故障。

Start by checking the battery: measure its voltage with a multimeter. A healthy 1.5 V cell should read close to 1.5 V. If the reading is very low, the battery is flat and must be replaced.

首先检查电池：用万用表测量其电压。一节完好的 1.5 V 电池读数应接近 1.5 V。如果读数很低，说明电池已耗尽，必须更换。

Next, inspect the lamp. Swap it with a known-working lamp to see if the fault lies in the bulb. Also, examine the filament inside the glass; a broken filament means the bulb has blown.

接下来，检查灯泡。用已知能正常工作的灯泡替换，看故障是否出在灯泡上。同时观察玻璃内的灯丝；灯丝断裂意味着灯泡烧坏了。

Finally, test the switch and the connecting wires. Use the continuity setting on the multimeter to check for any breaks in the circuit. Loose crocodile clips or damaged insulation can also break the loop.

最后，测试开关和连接导线。使用万用表的通断档检查电路是否有中断。松动的鳄鱼夹或破损的绝缘层也可能导致回路断开。

Once the fault is fixed, you can calculate the current flowing using Ohm’s law: I = V/R. If the lamp has a resistance of 10 Ω and the battery supplies 3 V, the current is I = 3 V / 10 Ω = 0.3 A.

故障排除后，你可以使用欧姆定律计算电流：I = V / R。如果灯泡电阻为 10 Ω，电池提供 3 V 电压，则电流 I = 3 V / 10 Ω = 0.3 A。

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5. Levers and Mechanical Advantage | 杠杆与机械效益

A lever is a simple machine that can amplify an input force. The mechanical advantage (MA) tells you how much the lever multiplies your effort.

杠杆是一种可以放大输入力的简单机械。机械效益 (MA) 告诉你杠杆能将你的作用力放大多少倍。

In a case study, you use a crowbar to lift a heavy crate. The distance from the fulcrum to the effort is 80 cm, and the distance from the fulcrum to the load is 20 cm. The mechanical advantage is calculated as MA = effort arm / load arm = 80 cm / 20 cm = 4.

在案例研究中，你用一根撬棍撬起重物。支点到力点的距离为 80 厘米，支点到重点的距离为 20 厘米。机械效益计算为 MA = 力臂 / 重臂 = 80 cm / 20 cm = 4。

This means your input effort is multiplied four times. If you push down with a force of 50 N, the lever exerts an upward force of about 200 N on the load (ignoring friction losses).

这意味着你的输入力被放大了四倍。如果你向下施加 50 牛的力，杠杆就会对重物施加大约 200 牛的向上力（忽略摩擦损耗）。

Different classes of levers arrange the fulcrum, load, and effort differently. A wheelbarrow is a class 2 lever where the load sits between the fulcrum and the effort, giving a high mechanical advantage for lifting soil.

不同类型的杠杆对支点、重物和施力点的排列方式不同。手推车属于第二类杠杆，其重点位于支点和力点之间，为铲起泥土提供了很高的机械效益。

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6. Sustainability in Product Design | 产品设计中的可持续性

Engineers today must consider the full product life cycle, from raw material extraction to disposal or recycling. A product that works well but harms the environment is not a truly successful design.

如今的工程师必须考虑产品完整的生命周期，从原材料提取到废弃或回收。一件产品如果功能良好却对环境造成危害，就不是真正的成功设计。

Take the case of a reusable water bottle. You might design it from recycled PET plastic, which reduces the need for virgin petroleum. The bottle should be robust so it lasts many years, further cutting waste.

以可重复使用的水瓶为例。你可以用回收的 PET 塑料来设计，从而减少对原生石油的需求。水瓶应该坚固耐用，能够使用多年，进一步减少废弃物。

During the design phase, evaluate the energy and water used in manufacturing. Select local suppliers to minimise transport emissions, known as product miles.

在设计阶段，要评估制造过程中消耗的能源和水资源。选择本地供应商以尽量减少运输排放，即所谓的“产品里程”。

At the end of its life, the bottle should be easy to recycle again. This is a ‘cradle-to-cradle’ approach. Avoid mixing materials that cannot be separated, such as a bottle with a non-removable metal label.

在使用寿命结束时，瓶子应易于再次回收。这就是“从摇篮到摇篮”的理念。避免使用无法分离的混合材料，例如带有无法拆卸金属标签的水瓶。

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7. Systems and Control: Input-Process-Output | 系统与控制：输入-过程-输出

Many engineering products are control systems that can be described using the Input-Process-Output (IPO) model. Understanding this helps you break down how a device functions.

许多工程产品都是控制系统，可以用“输入-过程-输出”(IPO) 模型来描述。理解这一点有助于你分解设备的工作方式。

As a case study, design an automatic night light. The input is a light-dependent resistor (LDR) whose resistance rises when it gets dark.

作为一个案例研究，设计一个自动夜灯。其中输入是一个光敏电阻 (LDR)，当环境变暗时，它的电阻值会上升。

The process stage uses a transistor or microcontroller to sense the change in voltage across the LDR and decide when to switch on. The output is an LED that illuminates the area.

在处理阶段，利用晶体管或微控制器检测光敏电阻两端电压的变化，并决定何时开启。输出则是一盏能照亮区域的 LED 灯。

You can draw a block diagram to communicate the system: [LDR sensor] → [Comparator circuit] → [LED module]. This makes the design clear before building it on a breadboard.

你可以绘制框图来表述系统：[LDR 传感器] → [比较器电路] → [LED 模块]。这样做能在面包板上搭建之前让设计清晰明了。

Testing the prototype involves covering the LDR to simulate darkness and measuring the voltage at the LED to ensure the system responds correctly across a range of light levels.

测试原型时，需要遮住光敏电阻来模拟黑暗环境，并测量 LED 两端的电压，以确保系统在多种光照水平下都能正确响应。

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8. Ergonomics and User-Centred Design | 人机工程学与以用户为中心的设计

Ergonomics is about designing products that fit the human body. Poor ergonomics can cause discomfort or even injury, so user trials are essential.

人机工程学关注的是设计契合人体的产品。糟糕的人机工程学可能引发不适甚至伤害，因此用户试用必不可少。

Case study: design a comfortable handle for a hand tool, such as a hammer or screwdriver. Begin by measuring the hand dimensions of different users to identify a suitable grip diameter, usually 30–40 mm for teens.

案例研究：为手动工具（例如锤子或螺丝刀）设计一个舒适的手柄。首先测量不同用户的手部尺寸，以确定合适的握柄直径，通常对青少年来说在 30–40 毫米之间。

Create several foam models with different shapes and textures. Ask testers to perform a repetitive task (like screwing) for one minute and then rate comfort on a scale of 1 to 5.

制作几种不同形状和纹理的泡沫模型。让测试者重复执行某项任务（如拧螺丝）一分钟，然后在 1 到 5 的等级上对舒适度进行评分。

Analyse the data to see which handle shape reduces fatigue. A contoured rubber grip that aligns with the natural curve of the palm often scores highest.

分析数据，看哪种手柄形状能减轻疲劳。符合手掌自然曲线的异形橡胶握把通常得分最高。

User-centred design also considers colour, weight, and balance. Your final prototype must combine the preferred ergonomic features into a product that is both functional and pleasant to use.

以用户为中心的设计还会考虑颜色、重量与平衡性。你的最终原型必须将首选的人机工程特征整合到一件既实用又令人愉悦的产品中。

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9. Modelling, Prototyping and CAD | 建模、原型制作与计算机辅助设计

Before manufacturing a final product, engineers create virtual 3D models and physical prototypes to test their ideas. CAD (Computer-Aided Design) allows you to visualise every detail precisely.

在制造最终产品之前，工程师会创建虚拟的 3D 模型和物理原型来测试创意。CAD（计算机辅助设计）能让你精确地可视化每一个细节。

In this case, you are asked to design a personalised keyring. Using Tinkercad (a free CAD tool), you can combine basic shapes, add text, and change dimensions easily.

在这个案例中，你被要求设计一款个性化的钥匙扣。使用 Tinkercad（一款免费的 CAD 工具），你可以轻松地组合基础形状、添加文字并改变尺寸。

Once the digital model is ready, you export it as an STL file and use a 3D printer to produce a physical prototype. Test the keyring for strength by attaching weights to the ring hole.

数字模型完成后，将其导出为 STL 文件，再用 3D 打印机制作出实体原型。通过在钥匙环孔上悬挂重物来测试钥匙扣的强度。

If the prototype breaks too easily, return to the CAD model and increase the thickness of critical sections, or add fillets to reduce stress concentrations. This iterative loop is fast and cost-effective.

如果原型太容易断裂，就回到 CAD 模型中，增加关键截面的厚度，或者添加圆角以降低应力集中。这种迭代循环既快速又经济。

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10. Evaluation and Iterative Improvement | 评估与迭代改进

The final, and possibly most important, stage of any engineering case study is evaluation. You must review your prototype against the original specification and identify what works and what does not.

任何工程案例研究的最后一个、或许也是最重要的阶段就是评估。你必须对照最初的设计规范检查原型，明确哪些部分有效、哪些地方不行。

Collect quantitative data, such as the maximum load a structure held, the current measured in a circuit, or the comfort score from a user survey. Display this data in a table or bar chart to compare versions.

收集定量数据，例如结构能承受的最大荷载、电路中测得的电流，或者用户调查中的舒适度评分。将这些数据放入表格或条形图中，以便比较不同版本。

Based on your evidence, propose at least three specific improvements. For example, ‘Replace the single paper tube with a laminated beam of three glued layers to increase bending strength.’

根据证据，提出至少三项具体的改进措施。例如，“将单根纸管替换为由三层粘合而成的层压梁，以提高抗弯强度。”

Implement one of the changes, build a second iteration, and test again. This process of plan, test, learn, and improve is what makes engineering a creative and evidence-based discipline.

实施其中一项变更，制作第二版迭代，并再次进行测试。这种计划、测试、学习、改进的过程，正是使工程学成为一门富有创造力且基于证据的学科的原因。

Published by TutorHao | Engineering Revision Series | aleveler.com

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