CPE I key terms

The ratio of a material's or structure's failure strength to the maximum stress it is expected to carry in service. A value above one provides margin against uncertainty in loads, material properties, and analysis.

A design method in which computed service stresses are kept below a permitted fraction of a material's strength. The permitted fraction is set by codes or by the factor of safety chosen for the application.

A design approach that applies separate load factors and resistance factors to check that a structure will not exceed defined failure conditions, such as strength, serviceability, fatigue, or stability limits.

A specific combination of loads and boundary conditions assumed to act on a structure at one time. Engineers analyze several load cases to find the governing worst-case demand on each element.

The permanent, essentially constant weight of a structure and its fixed attachments, such as beams, slabs, finishes, and equipment. It is estimated from material densities and geometry and is treated as sustained.

A variable load produced by occupancy, use, or environmental effects that may act intermittently or move across a structure. Design values come from codes or from measured or assumed usage patterns.

A plot of stress against strain obtained from a mechanical test. Its shape reveals stiffness, yield point, ultimate strength, ductility, and toughness, and it underpins most strength calculations for materials.

The stress at which a material begins to deform permanently, marking the end of elastic behavior. It is often the governing limit for design because excessive permanent deformation can make a part unusable.

The maximum stress a material can sustain before fracture or significant loss of load capacity. It is used with a factor of safety where yielding is acceptable or where brittle behavior governs.

The slope of the linear portion of a stress-strain curve, expressing how much stress is needed to produce a unit of elastic strain. A higher value means a stiffer material that deflects less under the same load.

Progressive damage and possible failure of a material subjected to repeated or fluctuating stress below its static strength. Cracks initiate and grow over many cycles, often without visible warning.

A local increase in stress caused by a geometric discontinuity such as a hole, notch, fillet, or sharp change in section. The concentration factor multiplies nominal stress and can drive fatigue or brittle fracture.

Sudden lateral instability of a slender member under compressive load, occurring at a critical load that depends on length, end conditions, and bending stiffness rather than on material strength alone.

The ratio of useful work or energy output to energy input for a process or device. It is always less than one in real systems because some energy is rejected or lost to irreversibility.

Movement of thermal energy by conduction, convection, or radiation driven by a temperature difference. Engineers size insulation, coolers, and exchangers by estimating these three modes together.

An accounting of all energy entering, leaving, and accumulating within a defined system boundary. It is the basis for sizing equipment, checking measurements, and identifying unaccounted losses.

The quantified range within which the true value of a measurement is expected to lie, combining contributions from instruments, calibration, environment, and procedure. It is reported with results so decisions reflect data quality.

Comparing an instrument's output against a reference standard of known value and adjusting or documenting the difference. Regular calibration establishes traceability and supports confidence in measured data.

The permissible variation in a dimension, property, or performance value around a specified target. Tolerances balance functional needs against manufacturing cost and must be compatible with measurement capability.

A structured, documented examination of a design by qualified reviewers against requirements, standards, and risk. It occurs at planned stages to catch errors early and record decisions and actions.

The documented linkage from each stakeholder need to design requirements, design elements, and verification evidence. It supports impact analysis when changes occur and demonstrates that every requirement is addressed.

Verification confirms that a design or product meets its specified requirements; validation confirms that it satisfies the intended use and stakeholder needs. Both require planned evidence, not opinion.

A systematic team method that lists how a product or process could fail, rates severity, occurrence, and detectability, and prioritizes actions to reduce risk. It is updated as the design matures.

A structured investigation to identify the underlying reason a problem occurred, rather than only its symptoms. Common tools include cause-and-effect diagrams, fault trees, and the five-whys technique.

A change made to eliminate the cause of a detected nonconformity so it does not recur. It differs from containment or correction, which only address the affected item itself.

A failure of a product, process, or document to meet a specified requirement. It must be recorded, segregated where relevant, dispositioned, and investigated for corrective action.

An independent, systematic examination of processes, records, or products against defined criteria. Findings are graded and tracked to closure, providing evidence that the quality system is effective.

A ranked approach to reducing risk, from most to least effective: eliminate the hazard, substitute a safer option, use engineering controls, apply administrative controls, then rely on personal protective equipment.

A step-by-step breakdown of a task that identifies hazards at each step and specifies controls before work begins. It is used for high-risk or infrequent tasks and is reviewed with the workers involved.

A formal written authorization controlling high-risk activities such as hot work, confined-space entry, or isolation of energy. It records hazards, precautions, isolations, and sign-offs before and after the task.

A procedure that isolates hazardous energy sources and applies locks and tags so equipment cannot be started or released during maintenance. Only the person who applied a lock removes it under defined exceptions.

A living record of identified risks, each with its cause, potential impact, likelihood, owner, planned response, and current status. It is reviewed at intervals and drives project and technical decisions.

A scheduling technique that models task durations and dependencies to find the longest path through a project network. Activities on that path have no float and delay the project if they slip.

A hierarchical decomposition of project scope into manageable deliverable-oriented elements. It provides the framework for estimating cost and duration, assigning responsibility, and controlling scope.

A performance measurement method comparing planned value, earned value, and actual cost to assess schedule and cost performance. Indexes and variances forecast likely outcomes and flag the need for corrective action.

Uncontrolled expansion of project scope through small, unapproved additions that erode budget and schedule. It is countered by formal change control and a clearly baselined work breakdown structure.

A formal process for proposing, evaluating, approving, and recording changes to a baselined design, schedule, or contract. It ensures impacts on cost, risk, and interfaces are assessed before implementation.

A situation in which a professional's personal, financial, or other interest could improperly influence judgment on behalf of an employer or client. It must be disclosed and managed, not concealed.

The published principles and rules governing professional conduct, typically covering public safety, competence, honesty, confidentiality, and fair dealing. Members accept enforcement of the code as a condition of practice.

The degree of skill and diligence that a reasonably prudent professional would exercise in similar circumstances. It is the benchmark used to judge whether conduct met accepted professional expectations.

Failure to exercise the standard of care owed to another, resulting in harm. A claim generally requires a duty, a breach of that duty, causation, and actual damage.

Reporting a genuine concern about illegal, unsafe, or unethical conduct to an authority able to act on it. Professional codes generally support raising concerns internally first where feasible.

Specific, timely, behavior-focused input intended to improve performance or work products. It describes observed facts and their impact, invites response, and agrees on next steps rather than assigning blame.

Fully concentrating on a speaker, paraphrasing to confirm understanding, and asking clarifying questions before responding. It reduces misunderstandings in requirements gathering, reviews, and conflict resolution.

A responsibility chart that assigns each activity to those Responsible, Accountable, Consulted, and Informed. It clarifies decision rights and reduces gaps and duplication in cross-functional teams.