ME 101 — Introduction to Mechanical Engineering: Freshman Fundamentals

A comprehensive vocabulary study set based on the ME 101 Freshman Fundamentals Study Guide, covering mechanical and thermal design, mechanics, materials, manufacturing, fluid dynamics, and energy.

Mechanical Engineering

A broad engineering discipline concerned with the design, analysis, manufacturing, testing, and operation of physical systems involving forces, motion, materials, fluids, heat, and energy.

Machine Design

A major area of mechanical engineering that encompasses mechanical behavior, machine elements, and manufacturing processes.

Thermal Design

A major area of mechanical engineering that encompasses thermodynamics, fluid mechanics, and heat transfer.

Order-of-Magnitude Estimation

An approximate calculation used to determine the general size or scale of a quantity.

Engineering Intuition

The ability to use physical understanding, experience, estimates, and scientific principles to judge whether an engineering result is reasonable.

Dimensional Consistency

The requirement that both sides of a physically valid equation must have compatible dimensions.

Force

A push or pull capable of changing an object's motion or causing deformation.

Weight

The downward gravitational force acting on an object, defined by the formula $W = mg$, where $g \approx 9.81\,\text{m/s}^2$ near Earth's surface.

Moment / Torque

The rotational effect produced by a force acting some perpendicular distance from an axis or pivot, expressed as $M = Fd$ with units of $\text{N}\cdot\text{m}$.

Equilibrium

A physical state in which an object experiences no linear acceleration ($\Sigma F = 0$) and no rotational acceleration ($\Sigma M = 0$).

Free-Body Diagram (FBD)

A simplified drawing showing an isolated object and the external forces and moments acting on it.

Metals

An engineering material class characterized as relatively stiff, often strong, usually ductile, often tough, capable of various fabrication methods (machined, forged, cast, rolled, drilled), and susceptible to corrosion in some cases.

Ceramics

An engineering material class characterized by being hard, wear resistant, corrosion resistant, high-temperature resistant, often brittle, and capable of providing electrical insulation.

Polymers

An engineering material class characterized as lightweight, relatively inexpensive, easily formed, corrosion resistant, and having lower stiffness than metals.

Composites

Materials made by combining different materials to obtain useful combinations of properties, such as carbon-fiber-reinforced polymer.

Normal Stress ($\sigma$)

The intensity of an internal force distributed across a cross-sectional area, calculated as $\sigma = \frac{F}{A}$ with the SI unit of pascal ($\text{Pa} = \text{N/m}^2$).

Normal Strain ($\varepsilon$)

A dimensionless measure of deformation relative to an object's original dimension, defined as $\varepsilon = \frac{\Delta L}{L_0}$.

Elastic Deformation

Temporary deformation where the material approximately returns to its original dimensions when the applied load is removed.

Plastic Deformation

Permanent deformation where the material does not completely return to its original shape after the applied load is removed.

Yielding

The point or region on a stress-strain curve where significant permanent deformation begins.

Ultimate Tensile Strength

The maximum engineering stress reached during a tensile test.

Fracture

The final breaking of a material specimen under applied load.

Ductility

The ability of a material to undergo significant plastic deformation before fracture.

Brittleness

The tendency of a material to fracture with relatively little plastic deformation.

Stiffness

A material's resistance to elastic deformation.

Strength

A material's ability to withstand stress without yielding or failing.

Young's Modulus ($E$)

A measure of material stiffness under linear elastic behavior, defined as the ratio of stress to strain ($E = \frac{\sigma}{\varepsilon}$).

Engineering Design

An iterative process used to develop solutions that satisfy specified requirements and constraints.

Prototype

A physical or virtual version of a proposed design used for evaluation and testing.

Product Archaeology

The practice of studying or disassembling an existing product to understand its components, materials, manufacturing, and operation.

Casting

A manufacturing process where material is placed into a mold, often in liquid form, and solidifies into the desired geometry.

Forging

A manufacturing process where material is shaped through compressive forces.

Rolling

A manufacturing process where material passes through rollers to reduce thickness or change its cross-section.

Extrusion

A manufacturing process where material is forced through a die to create a long component with a desired cross-section.

Machining

A manufacturing process where material is removed from a workpiece via operations such as turning, milling, drilling, grinding, or cutting.

CNC (Computer Numerical Control)

The use of computer instructions to control machine tools during the manufacturing of components.

Additive Manufacturing

A manufacturing process where components are built by adding material, usually layer by layer, such as 3D printing.

Work

The energy transferred when a force acts through a distance, defined for a constant parallel force as $W = Fd$ with the unit of joule ($\text{J}$).

Power

The rate at which work is performed or energy is transferred, calculated as $P = \frac{W}{t}$ with the unit of watt ($\text{W} = 1\,\text{J/s}$).

Kinetic Energy ($\text{KE}$)

The energy associated with motion, defined as $\text{KE} = \frac{1}{2}mv^2$, which quadruples if velocity doubles at constant mass.

Gravitational Potential Energy ($\text{PE}$)

The energy possessed by an object due to its elevation, defined as $\text{PE} = mgh$, where $h$ is height relative to a reference.

Elastic Potential Energy ($\text{PE}$)

The energy stored in a deformed elastic element, expressed as $\text{PE} = \frac{1}{2}kx^2$, where $k$ is spring stiffness and $x$ is spring deformation.

Conduction

The transfer of thermal energy through direct molecular interaction within or between materials.

Convection

Heat transfer occurring between a solid surface and a moving fluid (liquid or gas).

Radiation

The transfer of energy by electromagnetic radiation, which does not require direct contact between objects.

Fluid

A substance, such as a liquid or gas, that continuously deforms under shear stress.

Continuity Principle

The relationship governing steady incompressible one-dimensional flow ($A_1 V_1 = A_2 V_2$), dictating that velocity increases when flow area decreases at constant volume flow rate.

Bernoulli Principle

An expression for idealized steady incompressible flow relating pressure, velocity, and elevation: $P + \frac{1}{2}\rho v^2 + \rho gh = \text{constant}$.

Reynolds Number

A dimensionless quantity used to help characterize fluid-flow behavior as laminar or turbulent.

Laminar Flow

Fluid flow characterized by smooth, orderly motion in layers, typically occurring at low Reynolds numbers.

Turbulent Flow

Fluid motion containing irregular fluctuations and mixing, typically occurring at high Reynolds numbers.

Belt Drive

A power-transmission system that transfers power through friction between a belt and pulley over relatively large shaft spacing.

Chain Drive

A power-transmission system that uses positive mechanical engagement and does not rely solely on friction.

Gears

Toothed machine elements that transmit motion and power through positive mechanical engagement to deliver accurate velocity ratios.

Gear Ratio

The ratio of teeth on the driven gear to teeth on the driver gear ($\text{Gear Ratio} = \frac{N_{\text{driven}}}{N_{\text{driver}}}$).

Top Dead Center (TDC)

The highest vertical position reached by a piston within an internal combustion engine cylinder.

Bottom Dead Center (BDC)

The lowest vertical position reached by a piston within an internal combustion engine cylinder.

Four-Stroke Cycle

The internal combustion engine sequence consisting of intake, compression, power, and exhaust strokes.

CAD (Computer-Aided Design)

Software technology used to create part geometry, build assemblies, produce engineering drawings, and prepare models for analysis.