Engineering Terms
Defined & Explained

Range of frequencies over which a circuit, system, or channel operates effectively. Difference between upper and lower cutoff frequencies.

Maximum load per unit area that a soil can support without shear failure. Critical for foundation design.

Conservation of energy principle for fluid flow along a streamline. Relates pressure, velocity, and elevation in an ideal fluid.

Sudden lateral deflection or failure of a structural member under compressive load when a critical load is exceeded.

Ability of a component to store electrical charge. Ratio of stored charge to voltage across the component. Measured in Farads (F).

Time-dependent process by which saturated soil decreases in volume under sustained load as water is squeezed out of the pore spaces.

Slow, time-dependent plastic deformation of a material under sustained stress, especially at elevated temperatures.

Dissipation of energy in an oscillating system, reducing the amplitude of vibrations over time. Can be viscous, structural, or Coulomb damping.

Two-terminal semiconductor device that allows current to flow primarily in one direction. Acts as a one-way valve for electric current.

Thermodynamic property measuring the degree of disorder or randomness in a system. In isolated systems, entropy always increases (Second Law of Thermodynamics).

Ratio of the ultimate strength of a structure to the actual applied load. Provides a margin against unexpected loads or material defects.

Weakening or failure of a material caused by repeatedly applied cyclic loads, even below the ultimate tensile strength.

Numerical method for solving complex structural, thermal, and fluid problems by dividing the domain into smaller elements and solving equations for each.

Mathematical transform that decomposes a function of time into its constituent frequencies. Fundamental tool in signal processing and vibration analysis.

Rate of change of hydraulic head per unit distance in the direction of flow. Drives groundwater movement and seepage through soil.

Total opposition to alternating current flow in a circuit, combining resistance (R) and reactance (X). Measured in ohms (Ω).

Property of an electrical conductor that opposes changes in current flow by storing energy in a magnetic field. Measured in Henries (H).

The algebraic sum of all voltages around any closed loop in a circuit equals zero. Conservation of energy in electrical circuits.

Smooth, orderly fluid flow in parallel layers with no disruption between layers. Occurs at low Reynolds numbers (Re < 2300 for pipe flow).

Geometric property of a cross-section that quantifies its resistance to bending. Depends on the distribution of area about the neutral axis.

Sampling theorem stating that a signal must be sampled at least twice its highest frequency component to be accurately reconstructed without aliasing.

Fundamental relationship in electrical circuits stating that current through a conductor is directly proportional to voltage and inversely proportional to resistance.

Proportional-Integral-Derivative controller. Feedback control mechanism widely used in industrial control systems to maintain a desired setpoint.

Ratio of transverse strain to axial strain when a material is stretched or compressed. Characterizes how a material deforms in directions perpendicular to loading.

Ratio of real power (watts) to apparent power (volt-amperes) in an AC circuit. Indicates how efficiently electrical power is used.

Compressive stress deliberately applied to concrete before service loads to counteract tensile stresses that would otherwise cause cracking.

Electronic device or circuit that converts alternating current (AC) to direct current (DC) using diodes or thyristors.

Tendency of a mechanical system to oscillate with greater amplitude at certain frequencies (natural frequencies) than at others.

Dimensionless quantity used to predict flow patterns in fluid mechanics. Ratio of inertial forces to viscous forces.

Internal force in a structural member that acts parallel to the cross-section, caused by transverse loads or moments.

Ratio of the density of a substance to the density of a reference substance (usually water at 4°C). Dimensionless quantity used in material characterization.

Deformation of a material expressed as the ratio of change in length to original length. Dimensionless quantity.

Internal force per unit area within a material when subjected to external loading. Measured in Pascals (Pa) or psi.

In linear systems, the response to multiple inputs equals the sum of responses to each input individually. Applies to structural analysis, circuits, and wave mechanics.

Measure of a material's ability to conduct heat. Higher values indicate better heat conductors. Measured in W/(m·K).

Series of thermodynamic processes that returns a system to its initial state. Forms the basis of heat engines and refrigerators.

Rotational force or moment that causes an object to rotate about an axis. Product of force and perpendicular distance.

Passive electrical device that transfers electrical energy between two or more circuits through electromagnetic induction, changing voltage levels.

Chaotic, irregular fluid motion with eddies, vortices, and rapid variation in pressure and velocity. Occurs at high Reynolds numbers.

Measure of the stiffness of a solid material. Ratio of tensile stress to tensile strain in the elastic region.