Mechanical Engineering — Strand 5: Design and Development (Deep Study Notes)

Need

The underlying reason a product/system should exist.

Stakeholder

Anyone affected by the design, such as end users, manufacturers, and regulators.

Design Brief

A short statement that captures the problem context, user environment, success criteria, and constraints.

Requirement

A must-have condition the design must satisfy.

Specification

A measurable, testable statement that you can verify by inspection, analysis, or test.

Constraint

A hard limit that must not be exceeded, such as maximum voltage or cost.

Criterion

Something to optimize, often with trade-offs.

Quality Function Deployment (QFD)

A structured tool for mapping customer needs to engineering characteristics.

Verification

Checking if the correct equations were solved and if the model setup is right.

Validation

Determining if the model matches reality and if it solves the right equations.

Prototyping

Creating physical models to test ideas and learn about the design.

Failure Modes and Effects Analysis (FMEA)

A structured approach to identifying potential failures in a design.

Tolerance

The allowed dimensional variation in a design.

Load Path

How forces travel from the applied load to supports in a mechanical structure.

Factor of Safety (n)

A measure of safety margin; defined as $n = \frac{\text{allowable stress}}{\text{maximum stress}}$.

Fatigue Strength

The strength of a material under cyclic loading.

Axial Stress

Stress experienced by a member carrying a tensile or compressive force, defined by $\tau = \frac{F}{A}$.

Bending Stress

Stress varying across a beam, described by $\tau = \frac{M y}{I}$.

Deflection (δ)

The displacement of the beam under load, expressed as $\tau = \frac{F L^3}{3 E I}$.

Stress Concentration

Localized stress increase in materials due to geometric discontinuities.

Hand Calculations

Quick, transparent calculations for initial sizing of components.

Finite Element Analysis (FEA)

A computer-based method for predicting stress, deflection, and thermal response.

CAD

Computer-Aided Design, used for modeling and communication in engineering.

Design for Manufacture (DFM)

Designing products that are easy to manufacture.

Design for Assembly (DFA)

Designing products that are easy to assemble.

Standard Components

Pre-manufactured parts that can be integrated into designs to reduce cost and risk.

Lifecycle Thinking

Considering a product's lifespan from design to end-of-life.

Sustainability

Designing to minimize environmental impact and promote recyclability.

Iterative Development

The process of repeatedly revising and improving design through stages.

Configuration Control

Managing changes in design to maintain consistency.

Ethics in Engineering

The moral obligations engineers have to report data accurately and ensure safety.

Intellectual Property (IP)

Legal rights pertaining to inventions and designs.

Risk Management

Systematically identifying and mitigating potential risks in a project.

Verification Methods

Inspection, analysis, and test methods used to confirm specifications.

Prototypes

Models created to test design concepts and verify functionality.

Measurement Uncertainty

The doubt that exists about the result of a measurement.

Design of Experiments (DOE)

A systematic method for determining the relationship between factors affecting a process.

Proof-of-Concept Prototype

A prototype to demonstrate core functions work.

Functional Prototype

A prototype that operates like the intended final product for performance testing.

Production-Representative Prototype

A prototype that uses near-final materials and processes for validation.

Assembly Yield

The number of usable products produced relative to those that were attempted.

Technical Communication

Delivering clear and effective information regarding design choices.

Reliability

The likelihood that a system will perform its function over time.

Maintainability

The ease with which a system can be inspected, serviced, or repaired.

Safety Features

Design elements that prevent misuse and ensure user safety.

Regulatory Compliance

Meeting legal standards and guidelines set for product design.

Documentation Control

Keeping track of revisions and changes in engineering documents.

Root Cause Analysis

Investigating the underlying causes of a failure.

Design Review

A formal meeting to evaluate design progress and compliance with requirements.