Chartered Membership of IMechE (CEng MIMechE) Engineering Design, Development and Problem Solving Syllabus

What are the four common strategies for treating a risk?

Avoid (eliminate the cause), Reduce/Mitigate (lower likelihood or impact), Transfer (insure or contract out), and Accept/Retain (tolerate within appetite).

What is FMEA and what three numbers produce its Risk Priority Number?

Failure Mode and Effects Analysis systematically identifies potential failure modes and their effects. The Risk Priority Number is $$RPN = S \times O \times D$$ the product of Severity, Occurrence and Detection ratings (each typically 1-10).

What is the purpose of a sensitivity analysis when managing uncertainty?

It quantifies how variation in input parameters affects the output, identifying which uncertain inputs most strongly drive the result so that design effort, testing or tolerancing is focused where it matters most.

What is a Monte Carlo simulation used for in design under uncertainty?

It propagates probability distributions of uncertain input variables through a model using many random samples to produce a probability distribution of outcomes, giving confidence levels and likelihoods rather than a single deterministic answer.

Define 'factor of safety' and give its basic ratio form.

The factor of safety expresses the margin between a component's capacity and the load it actually carries, covering uncertainty: $$FoS = \frac{\text{material strength (or failure load)}}{\text{actual applied stress (or working load)}}$$

What is the difference between a factor of safety and a margin of safety?

Factor of safety is the ratio of strength to applied load. Margin of safety is $$MoS = \frac{\text{strength}}{\text{applied load} \times FoS_{required}} - 1$$ a positive value indicating the design exceeds the required factor of safety.

In detailed engineering, define direct (normal) stress and give its formula.

Direct stress is internal force per unit area acting normal to a cross-section: $$\sigma = \frac{F}{A}$$ where $F$ is the axial force and $A$ the cross-sectional area.

State the relationship between stress, strain and Young's modulus (Hooke's law).

Within the elastic region stress is proportional to strain: $$\sigma = E \, \varepsilon$$ where $E$ is Young's modulus and $\varepsilon = \frac{\Delta L}{L_0}$ is the engineering strain.

State the bending (flexure) formula relating stress, moment and curvature for a beam.

$$\frac{\sigma}{y} = \frac{M}{I} = \frac{E}{R}$$ where $\sigma$ is bending stress at distance $y$ from the neutral axis, $M$ the bending moment, $I$ the second moment of area, $E$ Young's modulus and $R$ the radius of curvature.

State the torsion equation for a circular shaft.

$$\frac{T}{J} = \frac{\tau}{r} = \frac{G\theta}{L}$$ where $T$ is torque, $J$ the polar second moment of area, $\tau$ the shear stress at radius $r$, $G$ the shear modulus, $\theta$ the angle of twist and $L$ the length.

What is the Finite Element Method (FEM) and what is its core idea?

FEM is a numerical technique for solving field problems (stress, thermal, fluid) by discretising a continuous domain into many small elements connected at nodes, approximating the governing equations over each element and assembling them into a global system that is solved for the unknowns.

Why must FEA (finite element analysis) results always be validated, and how?

Because results depend on assumptions, mesh quality, boundary conditions and material data, errors can be large yet plausible-looking. Validation uses mesh convergence studies, hand calculations, analytical checks, and comparison with physical test data.

What is mesh convergence in FEA?

It is the process of progressively refining the mesh until the result of interest (e.g. peak stress) changes negligibly between refinements, indicating the discretisation error is acceptably small and the solution is mesh-independent.

Distinguish between verification and validation in engineering analysis.

Verification asks 'are we solving the equations right?' (the model is built and computed correctly). Validation asks 'are we solving the right equations?' (the model correctly represents reality), typically confirmed against physical test data.

What is the purpose of tolerance stack-up analysis in detailed design?

It assesses how the accumulation of individual component tolerances affects the fit, clearance or performance of an assembly, ensuring the design functions across the full range of manufacturing variation.

Compare worst-case and statistical (RSS) tolerance analysis.

Worst-case sums tolerances arithmetically, guaranteeing assembly but giving the widest, most conservative result. Statistical (root-sum-square) combines them as $$T = \sqrt{\sum t_i^{2}}$$ giving a tighter, more realistic assembly variation based on probability.

In testing, distinguish verification testing from validation testing.

Verification testing confirms the product meets its specified requirements ('built right'). Validation testing confirms the product meets the user's actual needs in real use ('built the right thing').

What is a Verification and Validation (V&V) matrix?

A document mapping each requirement to the method (inspection, analysis, demonstration, or test) that will prove it is met, ensuring complete and traceable evidence that all requirements are satisfied.

Name the four standard methods of requirement verification.

Inspection (examination), Analysis (calculation/modelling), Demonstration (operational observation), and Test (controlled measurement against defined criteria). Often abbreviated I, A, D, T.

What is commissioning, and how does it differ from testing?

Commissioning is the process of bringing an installed system into operational service, verifying that all components and systems work together as intended in their final environment. Testing typically verifies individual components or functions; commissioning verifies the integrated, installed whole.

What is a Factory Acceptance Test (FAT) versus a Site Acceptance Test (SAT)?

A FAT verifies equipment performance at the manufacturer's premises before shipment. A SAT verifies it again after installation at the operating site, confirming correct integration and performance in its actual environment.

What is the difference between accuracy and precision in measurement during testing?

Accuracy is closeness of a measurement to the true value (low systematic error). Precision is the repeatability or closeness of repeated measurements to each other (low random scatter). A result can be precise but inaccurate, or accurate but imprecise.

What is calibration and why is traceability important in test measurement?

Calibration compares an instrument's readings against a reference standard and adjusts/records the deviation. Traceability means that reference links through an unbroken chain to a recognised national/international standard, giving confidence and legal defensibility to measurements.

Describe the PDCA cycle used in continuous improvement.

Plan (identify and plan a change), Do (implement on a small scale), Check (measure and study the results), Act (adopt, adjust or abandon). It is an iterative loop for incremental improvement, also called the Deming cycle.

What is the difference between Kaizen and a breakthrough (Kaikaku) improvement?

Kaizen is continuous, incremental, small-step improvement involving everyone over time. Kaikaku (breakthrough) is a radical, large step-change, often driven by new technology or process redesign, delivering a major leap in performance.

What are the 'eight wastes' targeted by Lean engineering (DOWNTIME)?

Defects, Overproduction, Waiting, Non-utilised talent, Transportation, Inventory, Motion, and Excess processing.

What does Six Sigma aim for, and what does the sigma level signify?

Six Sigma aims to reduce process variation so defects are extremely rare. A six-sigma process has the specification limits at $\pm 6\sigma$ from the mean, corresponding to about 3.4 defects per million opportunities (allowing for a $1.5\sigma$ shift).

What is the DMAIC framework in Six Sigma?

Define (the problem and goals), Measure (current performance), Analyse (root causes), Improve (implement and verify solutions), Control (sustain the gains). It is a structured data-driven improvement method.

What is root cause analysis, and name two common tools for it.

Root cause analysis identifies the fundamental underlying cause of a problem rather than its symptoms. Common tools include the '5 Whys' (repeated questioning) and the Ishikawa/fishbone (cause-and-effect) diagram.

Distinguish between incremental, radical, and disruptive innovation.

Incremental innovation makes small improvements to existing products/processes. Radical innovation introduces a fundamentally new technology or capability. Disruptive innovation creates a simpler/cheaper offering that initially serves an overlooked market then displaces established ones.

What is the difference between an invention and an innovation?

An invention is the creation of a new device, method or idea. Innovation is the successful exploitation of that invention to deliver value, i.e. bringing it into practical, commercial or beneficial use.

What is the 'fuzzy front end' of innovation?

It is the early, ill-defined phase before formal product development where opportunities are identified, ideas generated and concepts explored. It is high in uncertainty but is where the greatest influence over eventual value and cost is exerted.

What is an innovation 'S-curve' and what does it depict?

It plots a technology's performance against effort or time, showing slow initial progress, rapid growth, then maturity/plateau. It signals when a technology is approaching its limits and a new S-curve (technology) may be needed.

What is a stage-gate process in managing innovation/product development?

It divides development into stages of work separated by decision gates where progress, risks and business case are reviewed and a go/kill/hold/recycle decision is made, controlling investment and filtering out weak projects early.

Name the four principal categories of formal intellectual property rights.

Patents (inventions), Trade marks (brand identifiers), Registered designs (appearance), and Copyright (original creative/literary works). Trade secrets and unregistered design rights are also IP forms.

What three core criteria must an invention satisfy to be patentable?

It must be novel (new, not previously disclosed), involve an inventive step (non-obvious to a skilled person), and be capable of industrial application (useful/manufacturable). It must also not fall within excluded categories.

Why is keeping an invention confidential before filing a patent critical?

Because public disclosure before the filing date destroys novelty and can invalidate the patent. Prior disclosure means the invention is no longer 'new', so confidentiality (or an NDA) must be maintained until a priority filing is made.

What protection does a patent grant and for how long (typically)?

A patent grants the owner the exclusive right to prevent others from making, using, selling or importing the invention, in exchange for public disclosure. Protection typically lasts up to 20 years from filing, subject to renewal fees.

Compare a patent with keeping a trade secret as exploitation strategies.

A patent gives time-limited exclusive rights but requires full public disclosure and lapses after ~20 years. A trade secret can last indefinitely and needs no disclosure, but offers no protection if independently discovered or reverse-engineered, and relies on secrecy being maintained.

What is licensing as a route to IP exploitation?

Licensing grants another party the right to use the IP (make/use/sell) in return for royalties or fees, while retaining ownership. It enables value capture without the licensor manufacturing or marketing the product itself.

What is 'freedom to operate' (FTO) and why must engineers check it?

FTO is the ability to develop, make and sell a product without infringing the valid IP rights of others. Engineers must check it to avoid costly infringement litigation and to confirm the design can legally be commercialised.

Define whole-life (life-cycle) engineering thinking.

It is the approach of considering all stages of a product's life - raw materials, manufacture, distribution, operation/use, maintenance, and end-of-life disposal/recycling - when making design decisions, optimising for total value, cost and impact rather than just initial performance.

What is whole-life cost (life-cycle cost) and what does it include?

It is the total cost of a product or asset over its entire life: acquisition/capital cost (CAPEX) plus operating, maintenance, energy and downtime costs (OPEX), plus end-of-life disposal/decommissioning costs, often discounted to present value.

What is a Life Cycle Assessment (LCA) and what are its four phases per ISO 14040?

LCA quantifies the environmental impacts of a product across its life. The four phases are: Goal & scope definition, Inventory analysis (LCI), Impact assessment (LCIA), and Interpretation.

What is embodied energy (and embodied carbon) of a product?

Embodied energy is the total energy consumed to extract, process, manufacture and deliver a material or product; embodied carbon is the associated total greenhouse-gas emissions. Both are 'locked in' before the product is even used.

Explain the difference between a linear economy and a circular economy.

A linear economy follows 'take-make-dispose', extracting resources, using them once and discarding them. A circular economy keeps materials and products in use through reuse, repair, remanufacture and recycling, designing out waste and regenerating resources.

State the waste hierarchy from most to least preferred option.

Prevention (reduce), then Reuse, then Recycle, then Recovery (e.g. energy from waste), and finally Disposal (landfill) as the least preferred.

What is Design for Manufacture and Assembly (DFMA) and its main goal?

DFMA is designing products to be easy and economical to manufacture and assemble - typically by reducing part count, simplifying assembly, and standardising components - so as to minimise cost, time and defects while maintaining function.

What is Design for X (DfX) and give three examples of the 'X'.

DfX is a family of design guidelines that optimise a product for a particular life-cycle attribute. Examples include Design for Manufacture, Design for Assembly, Design for Maintainability, Design for Reliability, Design for Disassembly/Recycling, and Design for Cost.

Define reliability and the bathtub curve.

Reliability is the probability that an item performs its required function without failure for a stated period under stated conditions. The bathtub curve plots failure rate over time, showing high early 'infant mortality' failures, a low constant 'useful life' rate, then rising 'wear-out' failures.

Define MTBF and MTTR, and how they combine into availability.

MTBF is Mean Time Between Failures; MTTR is Mean Time To Repair. Availability is $$A = \frac{MTBF}{MTBF + MTTR}$$ representing the fraction of time the system is operational.

In whole-life thinking, what is the trade-off between CAPEX and OPEX?

A lower initial capital cost (CAPEX) often increases running and maintenance costs (OPEX) over the asset's life, and vice versa. Whole-life thinking optimises the total of both rather than minimising one in isolation, since the cheapest to buy may be costliest to own.

Why does the early design stage have the greatest leverage over whole-life cost and impact?

Because although early design consumes little expenditure, the decisions made there (concept, materials, architecture) commit the large majority - typically around 70-80% - of the total life-cycle cost and environmental impact, which become progressively harder and costlier to change later.