CEAD Lesson 3

Problem Definition & Identification

Defining the problem clearly and precisely

• Identifying user needs and expectations

• Establishing target requirements and constraints (technical, budget,

timeline)

• Importance of a well-scoped problem for successful design

outcomes

From Need to Definition

Customer Need vs. Engineering Problem

Need: Broad, subjective user request (e.g., "Make a lighter backpack"). Problem Statement: Precise, quantifiable objective (e.g., "Reduce pack weight below 500g while supporting a 2 kg payload").

Defining Scope & Boundaries

Identifies target users, operating

conditions, and operational limits.

Prevents scope creep early in the design

cycle.

Engineering Criteria (Goals to Maximize)

Desirable performance traits and features. Examples: High efficiency, low manufacturing cost, compact form factor, long battery life

Engineering Constraints (Strict Limits)

Non-negotiable boundaries that must be met. Examples: Safety regulations, maximum budget, dimensional envelope, completion deadline.

BACKGROUND RESEARCH

Exploring Existing Solutions

Exploring Existing Solutions Patent Searches: Avoid reinventing the wheel or committing patent infringement. Literature Reviews & Competitor Analysis: Evaluate current market standards, technical papers, and existing product flaws.

Structured Brainstorming

SCAMPER: Substitute, Combine, Adapt, Modify, Put to

another use, Eliminate, Reverse.

Mind Mapping & Brainwriting: Generating a wide volume of

unrefined ideas rapidly.

Concept Selection (Pugh Decision Matrix)

Evaluate generated concepts against key criteria (e.g., cost, complexity, performance). Systematically filter down to 2-3 viable design candidates.

Virtual Modeling & Simulation

CAD & FEA: Using Computer-Aided Design and Finite Element Analysis to test stress, heat, and fluid dynamics before physical manufacturing.

Fidelity Progression

Low-Fidelity: Rapid cardboard, foam, or 3D prints for fit, scale, and spatial checks. High-Fidelity: Functional prototypes built with final materials to evaluate real-world structural integrit

Performance & Destructive Testing

Measuring physical prototypes against initial constraints (load limits, fatigue, weather conditions).

The Refinement Cycle

Identifying failure points early saves significant engineering costs. Updating CAD models based on test data before moving to mass production.

Material Selection Criteria

(yield strength, thermal expansion, corrosion resistance, weight) to operational environments.

Structural Integrity & Load Capacity

Ensuring components withstand static, dynamic, and thermal loads without structural deformation or material fatigue.

Design for Manufacturing & Assembly (DFMA)

Simplifying part geometry, reducing total part count, and standardizing fasteners to lower production costs and assembly time.

Reliability & Maintainability

Mean Time Between Failures (MTBF): Predicting component lifespan. Ease of Maintenance: Designing accessible components for modular replacement and routine field servicing.

Economic Viability&Cost Structure

Capitial vs Operational Expenditure

CapEx: Upfront costs for tooling, machinery,

and initial R&D.

OpEx: Ongoing costs for raw materials, labor,

energy, and distribution.

Unit Economics Margin Target

Balancing production cost per unit

against target retail price to ensure

profitability

Design for Sustainability (DfE) & Life Cycle

Assessment (LCA)

Evaluating environmental impact from raw

material extraction, through manufacturing

and usage, to disposal or recycling.

Factor of Safety (FoS)

Operating margin added to design equations

to account for unexpected stress, structural

fatigue, or material variations.

These are the typical FoS values used in engineering:

Aerospace/Aircraft: FoS ≈ 1.2 to 1.5; a low margin because

extra weightincreases fuel cost and requires precise

testing (can hold 20% to 50% more stress than its max

expected load)

Buildings&Structures: FoS ≈ 2.0 to 3.0; moderate

margin to handle unexpected structural loads and

earthquakes (100% to 200% expected weightload)

Elevator&Cables: Fos ≈ 3.0 to 5.0+; High margin ofrisk to

human life an unquantifiable shock loads (200% to 400%+

expected weightload)

Real-World Examples

Anthropometrics in Design

Using statistical human physical data (sizing for the 5th to 95th percentiles) to accommodate diverse user body types.

Biomechanical Usability

Minimizing physical strain, posture fatigue, repetitive motion injuries, and excessive force requirements during operation.

Standards:

Agreed-upon technical rules, operational guidelines, or definitions that ensure consistent product quality and interchangeability.

Codes:

Sets of standards officially adopted by legal or governmental authorities that carry the force of law.

Core Purpose of Compliance

Guarantees public safety, consumer trust,

environmental compliance, and global

cross-compatibility between vendors.

International Organization for Standardization

Focus: Universal quality

and environmental

management.

Key Standard: ISO 9001

(Quality Management

Systems).

Purpose: Ensures

consistent product

quality and smooth

international trade.

Institute of Electrical and

Electronics Engineers

Focus: Electrical,

electronic, and software

systems.

Key Standard: IEEE

802.11 (Wi-Fi networking

protocols).

Purpose: Guarantees

universal cross-brand

hardware and network

compatibility.

American Society of Mechanical Engineers

Focus: Mechanical

engineering,

manufacturing, power

generation, and design.

Key Standard: The Boiler

and Pressure Vessel Code

(BPVC).

Purpose: Ensures public

safety and operational

reliability in mechanical

systems and manufacturing.

American National

Standards Institute

Focus: National accreditation and safety gear specs. Key Standard: ANSI Z87.1 (Industrial eye/face protection). Purpose: Coordinates national technical standards with global regulatory bodies.