📚 Year 11 CCEA Engineering: Case Study Practical Drills | Year 11 CCEA 工程：案例分析实战演练
Engineering is about solving real-world problems through a systematic design process. In CCEA GCSE Engineering, case study questions test your ability to analyse a given scenario, apply technical knowledge, and propose justified solutions. This article provides hands-on practice drills using a sample product — a portable folding phone stand made from sustainable materials.
工程学是通过系统化的设计过程解决现实世界的问题。在 CCEA GCSE 工程学中，案例分析题考查你分析给定情境、应用技术知识并提出合理解决方案的能力。本文以一款利用可持续材料制作的便携可折叠手机支架为例，提供实战演练。
1. Understanding the Engineering Problem | 理解工程问题
A local start-up wants to design a lightweight, foldable stand for smartphones that can also hold small tablets. The product should be made from recycled or low-impact materials and must appeal to students and remote workers who value sustainability. The design brief states: "Design a portable phone stand that folds flat, supports devices in both portrait and landscape orientations, uses eco-friendly materials, and can be manufactured in small batches. Target unit cost is under £5."
一家本地初创公司希望设计一款轻便、可折叠的智能手机支架，同时也能支撑小型平板。产品应使用回收或低影响材料制作，并吸引重视可持续性的学生和远程工作者。设计简报指出："设计一款便携式手机支架，可折叠平放，支持设备在竖屏和横屏下使用，使用环保材料，并能进行小批量制造。目标单位成本低于5英镑。"
Key constraints identified include a maximum weight of 200 g, a folded thickness less than 10 mm, and compliance with UKCA safety marking for consumer products. The brief also hints that the stand must endure at least 5000 open-close cycles without failure.
确定的关键约束条件包括最大重量 200 克，折叠厚度小于 10 毫米，以及符合消费产品的 UKCA 安全标志要求。简报还暗示该支架必须能承受至少 5000 次开合循环而不发生故障。
2. Research and Specification | 研究调查与规范
Market research shows that users prefer stands with non-slip feet and the ability to adjust viewing angle. Environmental research reveals that bamboo and recycled polypropylene (rPP) have lower carbon footprints than virgin plastics. Based on this, an engineering specification is drawn up.
市场调研显示用户偏好带有防滑底座且能调节观看角度的支架。环境研究揭示竹材与再生聚丙烯 (rPP) 的碳足迹低于新制塑料。基于这些，制定了一份工程规范。
| Parameter | Value | Reason / Note |
|---|---|---|
| Folded thickness | ≤ 10 mm | Must fit in a laptop sleeve |
| Mass | ≤ 200 g | Portability requirement |
| Load capacity | ≥ 2 kg | Supports tablets up to 12.9" |
| Angle adjustment | 3 positions (30°, 45°, 60°) | Ergonomic viewing |
| Material | 70% bamboo, 30% rPP | Sustainable, stiff, cost-effective |
| Cycle durability | ≥ 5000 folds | Lifetime reliability |
| Unit cost | ≤ £4.80 | Below target to allow margin |
研究后，规范表格如下：
| 参数 | 数值 | 原因 / 说明 |
|---|---|---|
| 折叠厚度 | ≤ 10 mm | 必须可放入笔记本电脑套 |
| 质量 | ≤ 200 g | 便携性要求 |
| 承载能力 | ≥ 2 kg | 支撑最大 12.9 英寸平板 |
| 角度调节 | 3 档 (30°、45°、60°) | 符合人体工学的观看 |
| 材料 | 70% 竹材，30% rPP | 可持续、高刚性、成本效益好 |
| 循环耐久性 | ≥ 5000 次折叠 | 使用寿命可靠性 |
| 单位成本 | ≤ 4.80 英镑 | 低于目标以留出利润空间 |
3. Generating Design Ideas | 设计方案生成
Two initial concepts are sketched. Concept A uses two hinged bamboo arms with snap-fit plastic joints; it folds flat like a pair of scissors. Concept B is a single sheet of recycled polypropylene that is laser-cut and folded into an origami-style shape with living hinges.
初步绘制了两种概念方案。概念 A 采用两根铰接的竹制臂，配有卡扣式塑料接头，像剪刀一样折叠平放。概念 B 是一整片再生聚丙烯，通过激光切割并折叠成带有弹性铰链的折纸风格形状。
Concept A offers a premium feel and adjustable angles but has higher part count. Concept B is cheaper and simpler to manufacture, but the living hinge may degrade faster with repeated folding.
概念 A 提供高级质感并可调节角度，但零件数量较多。概念 B 更便宜且制造简单，但弹性铰链在反复折叠下可能老化更快。
After a quick weighted matrix evaluation, Concept A scores higher on durability and user experience and is chosen for further development.
经过快速加权矩阵评估，概念 A 在耐用性和用户体验上得分更高，被选为进一步开发的方案。
4. Developing and Modelling | 方案开发与建模
stress in the arm when a 2 kg load is applied at the tip. The critical cross-sectional area at the hinge slot is 4 mm × 8 mm = 32 mm². The bending moment leads to a maximum tensile stress estimated at:
使用 CAD 软件对所选方案进行建模。每条臂长 120 mm，宽 15 mm，厚 4 mm。采用有限元分析 (FEA) 检查在臂端施加 2 kg 负载时的应力。铰链槽处的临界横截面积为 4 mm × 8 mm = 32 mm²。弯矩导致的最大拉应力估算为：
σ = M c / I ≈ 12.5 MPa
The bamboo composite has a tensile strength of ~35 MPa, giving a safety factor of about 2.8, which meets the requirement. The model also ensures the folded thickness is exactly 9.8 mm, satisfying the specification.
竹复合材料抗拉强度约为 35 MPa，安全系数约为 2.8，满足要求。该模型同时确保折叠厚度精确为 9.8 mm，符合规范。
5. Material Selection | 材料选择
The final design uses a bamboo fibre composite for the main arms and recycled polypropylene (rPP) for the hinge components and non-slip pads. A comparison of candidate materials is shown in the table below.
最终设计在主体臂部使用竹纤维复合材料，在铰链部件和防滑垫上使用再生聚丙烯 (rPP)。候选材料的对比如下表所示。
| Material | Density (g/cm³) | Tensile Strength (MPa) | Sustainability | Cost |
|---|---|---|---|---|
| Bamboo composite | 1.2 | 35 | Renewable, biodegradable | Medium |
| rPP | 0.9 | 25 | 100% recycled | Low |
| PLA bioplastic | 1.25 | 50 | Compostable, but brittle | High |
中文对照：
| 材料 | 密度 (g/cm³) | 抗拉强度 (MPa) | 可持续性 | 成本 |
|---|---|---|---|---|
| 竹复合材料 | 1.2 | 35 | 可再生，可生物降解 | 中等 |
| rPP | 0.9 | 25 | 100% 回收材料 | 低 |
| PLA 生物塑料 | 1.25 | 50 | 可堆肥，但较脆 | 高 |
Bamboo composite is chosen for its balance of strength, sustainability and cost, with rPP serving as a lightweight, low-cost complement for the hinge area.
选择竹复合材料是因为它在强度、可持续性和成本之间取得平衡，而 rPP 则作为铰链区域轻便且低成本的补充。
6. Manufacturing Planning | 制造计划
The manufacturing sequence for 100 units is planned as follows:
100 件产品的制造顺序规划如下：
- Step 1: Laser-cut bamboo laminate sheets into arm blanks (tolerance ± 0.1 mm).
- Step 2: CNC-drill hinge pin holes (diameter 3 mm).
- Step 3: Injection mould rPP hinge clips and non-slip feet.
- Step 4: Sand and apply a thin water-based varnish to bamboo arms.
- Step 5: Snap-fit assembly of arms and clips; insert stainless steel hinge pin.
- Step 6: Quality inspection: check fold thickness, angle positions, and cycle test on sample.
- 步骤 1： 激光切割竹层压板材成臂部毛坯（公差 ± 0.1 mm）。
- 步骤 2： CNC 钻孔铰链销孔（直径 3 mm）。
- 步骤 3： 注塑成型 rPP 铰链卡扣和防滑底座。
- 步骤 4： 打磨并涂覆薄层水性清漆于竹臂上。
- 步骤 5： 卡扣组装臂部与卡扣；插入不锈钢铰链销。
- 步骤 6： 质量检验：检查折叠厚度、角度档位，并对样品进行循环测试。
The use of standardised parts (hinge pin, snap-fit geometry) reduces tooling cost and allows for easy scaling.
采用标准件（铰链销、卡扣几何）降低了模具成本，并便于规模化生产。
7. Prototyping and Testing | 原型制作与测试
A functional prototype is built using 3D-printed PLA for the arms (to simulate stiffness) and laser-cut rPP clips. Testing results:
使用 3D 打印 PLA 制作臂部原型（以模拟刚度），并激光切割 rPP 卡扣，构建功能原型。测试结果：
- Folded thickness: 9.7 mm — meets specification.
- Maximum load before slippage: 2.3 kg — exceeds 2 kg target.
- Angle retention after 100 cycles: angles remain within ±1° — acceptable.
- Cycle test: after 2000 folds, slight wear visible on rPP hinge, but no failure.
- 折叠厚度：9.7 mm — 符合规范。
- 滑落前最大负载：2.3 kg — 超过 2 kg 目标。
- 100 次循环后角度保持：角度偏差在 ±1° 以内 — 可接受。
- 循环测试：2000 次折叠后，rPP 铰链可见轻微磨损，但未失效。
User feedback highlights the need for a softer pad to prevent phone scratching, which will be addressed in the next iteration.
用户反馈强调了需要更柔软的垫子以防刮伤手机，这将在下一个迭代中解决。
8. Evaluation and Improvement | 评估与改进
The prototype meets nearly all specification points except the 5000-cycle target. To improve durability, the hinge geometry can be optimised by thickening the flexural area and using a glass-fibre reinforced rPP. Additionally, adding micro-suction tape to the support face will prevent device slip without increasing thickness significantly.
原型几乎满足所有规范要求，但 5000 次循环目标尚未达到。为提高耐久性，可优化铰链几何形状，加厚弯曲区域并使用玻纤增强 rPP。此外，在支撑面添加微吸力胶带可在不明显增加厚度的情况下防止设备滑动。
A cost analysis shows that switching to reinforced rPP adds £0.15 per unit, still keeping the unit cost at £4.65, well within the £5 budget.
成本分析显示，改用增强 rPP 每件增加 0.15 英镑，单位成本保持在 4.65 英镑，仍在 5 英镑预算之内。
9. Real-World Case: Sustainable Phone Stand | 现实案例：可持续手机支架
Consider the commercial product 'EcoStand Mini', a bamboo and recycled plastic stand that won a Green Design award. Its key engineering features include a patented 'slotted knuckle' hinge that allows silent angle adjustment and a bi-injected TPE grip ring. By studying such products, you learn that small details — like edge chamfers and weight distribution — can dramatically improve user perception and durability.
以商业产品 'EcoStand Mini' 为例，这是一款获得绿色设计奖的竹材与再生塑料支架。其主要工程特征包括专利的"槽口关节"铰链，可实现静音角度调节，以及双注塑 TPE 抓握环。通过研究此类产品，你会发现如边缘倒角和重量分配等细微之处能够显著提升用户感受和耐用性。
This real-world case shows how GCSE Engineering principles (materials, mechanisms, manufacturing) are applied in industry, reinforcing the importance of iterative testing and sustainable design thinking.
这一现实案例展示了 GCSE 工程学原理（材料、机构、制造）如何在工业中应用，并强调了迭代测试与可持续设计思维的重要性。
10. Exam-Style Case Study Practice | 考试风格案例分析练习
Now test yourself with a fresh scenario. Read the brief and plan how you would respond in a CCEA Engineering exam.
现在用一个新场景来检验自己。阅读简报，并规划你将在 CCEA 工程考试中如何作答。
Scenario: 'A charity wants a portable, solar-powered USB charger for use in disaster relief. It must charge two phones simultaneously, fold to A5 size, weigh under 300 g, and survive a 1-metre drop. Target production is 500 units initially.'
场景： "某慈善机构需要一款用于灾难救援的便携式太阳能 USB 充电器。它必须能同时为两部手机充电，折叠至 A5 大小，重量不超过 300 克，并能承受 1 米跌落。初步目标产量为 500 件。"
Think about:
请思考：
- List the key design criteria and constraints and explain one environmental consideration.
- Suggest two possible casing materials, justifying your choice with reference to properties and sustainability.
- Describe a simple test to verify the 1-metre drop resistance. Include what you would measure and what would be a pass/fail criterion.
- Outline a manufacturing process for the casing, identifying one quality control check.
- 列出关键设计标准与约束条件，并说明一项环境考量。
- 推荐两种可能的外壳材料，并参照性能和可持续性论证你的选择。
- 描述一个简单的测试以验证 1 米跌落抗性。包括你会测量什么，以及通过/不通过的标准。
- 概述外壳的制造过程，并指出一项质量控制检查。
Use the same engineering design process steps covered in earlier sections to structure your answers — define the problem, specify, develop, test and evaluate.
运用先前小节中涵盖的相同工程设计流程步骤来组织你的答案——定义问题、制定规范、方案开发、测试与评估。
Published by TutorHao | Engineering Revision Series | aleveler.com
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