Laminate, Laminated As a verb, to bond together in layers; as a noun, a material produced by bonding together layers of material.
Lateral Force A force acting generally in a horizontal direction, such as wind, earthquake, or soil pressure against a foundation wall.
Lateral Thrust The horizontal component of the force produced by an arch, dome, vault, or rigid frame.
Lattice An arrangement in space of isolated points in a regular pattern, which for example show the positions of atoms, molecules, or ions in the structure of a crystal.
Lattice of mass (full and partial) A distribution of contiguous mass with a fixed arrangement of open voids.
Leverage The mechanical advantage gained by using a pivot to concentrate a force.
Linear Pertaining to or represented by lines.
Linear density Mass per unit length.
Lintel A beam that carries the load of a wall across a window or door opening.
Live Load The weight of snow, people, furnishings, machines, vehicles, and goods in or on a building.
Load A weight or force acting on a structure.
Load-deflection diagram Plot of load versus corresponding deflection.
Loadbearing Supporting a superimposed weight or force.
Masonry Brickwork, blockwork, and stonework.
Masonry Unit A brick, stone, concrete block, glass block, or hollow clay tile intended to be laid in mortar.
Mass The quantity of matter in an object.
Material Forms of matter derived from 92 natural elements.
Materials-centered engineering Engineering methodologies in which material selection and exterior component design normally precede internal architectural and manufacturing considerations, e.g., RMT architecture and rapid manufacturing alternatives. For example, metals are essentially isotropic and homogeneous and have predictable properties; thus, material selection and component design for metals normally precede other considerations.
Materials Science is based on the physics and chemistry of the solid state and embraces all aspects of engineering materials, including metals and their alloys, ceramic materials such as glasses, bricks and porcelain insulators, polymers such as plastics and rubbers together with semiconducting and composite material. Materials Science extends from the extraction of the materials from their mineral sources and their refining and fabrication into finished products; it examines their chemical, crystal, molecular and electronic structure because structure influences not only a material's magnetic and electronic characteristics but also its mechanical properties such as strength; it studies the degradation of materials in service by wear, corrosion and oxidation and is concerned with developing methods of combating these; it considers the proper selection of materials for particular applications and the development of new materials for today's sophisticated technology.
Matrix Material used to bind or house the reinforcement material. In Reflexive Material Technology, the matrix bears little or no stress.
Maximum fiber stress Maximum tensile or compressive stress in a homogeneous flexure or torsion test specimen. For a specimen loaded as a simple beam at its midpoint, maximum fiber stress occurs at mid-span and may be calculated by the formula (for rectangular specimens):
where S is maximum fiber stress; P, load; L, span; b, width of the beam; and d, depth of the beam. For a circular cross section member loaded in torsion, maximum fiber stress may be calculated by the following formula:
where T is twisting moment; r, original outer radius and J, polar moment of inertia of original cross section.
Mean stress Algebraic difference between maximum and minimum stress in one cycle of fluctuating loading, as in a fatigue test. Tensile stress is considered positive and compressive stress negative.
Mechanical Force Force which acts on an object.
Mechanical properties The properties of a material, such as compressive and tensile strengths and modulus, that are associated with elastic and inelastic reaction when force is applied.
Member An element of a structure such as a beam, a girder, a column, a joist, a piece of decking, a stud, or a chord of a truss.
Metals Metallic materials are normally combinations of metallic elements. They have large numbers of nonlocalized electrons; that is, these electrons are not bound to particular atoms. Many properties of metals are directly attributable to these electrons. Metals are extremely good conductors of electricity and heat and are not transparent to visible light; a polished metal surface has a lustrous appearance. Metals are quite strong, yet deformable, which accounts for their extensive use in structural applications.
Micrometer Micro; a unit of length equal to 10-6 meter.
Millennium, -nia Period of 1,000 years.
Minimal Edge Shortest possible edge under a given set of conditions.
Minimal Network Any combination of intersecting or interconnecting units, such as rods, bars, filaments, lines, passages, channels, etc., of the shortest possible length under a given set of conditions.
Minimal Surface A surface with a mean curvature of zero.
Minimum bend radius Minimum radius to which a sheet or wire can be bent to a specified angle without failure.
Modulus A measure of the stiffness of a material during the first part of its bending process, expressed in N/mm2 or MPa. The higher the reported value, the stiffer the material.
Modulus in bending Ratio of maximum fiber stress to maximum strain, within elastic limit of stress-strain diagram obtained in flexure test. Alternate term is flexural modulus of elasticity.
Modulus in compression The ratio of compressive stress to strain within elastic limits of the material.
Modulus in flexure The ratio of the flexure stress to strain, within elastic limits of the material.
Modulus of Elasticity An index of the stiffness of a material, applicable for example to the bending of a beam (see Young's Modulus). The ratio of stress to strain in a material that is elastically deformed. The slope of the straight-line portion of a stress-strain diagram. Tangent modulus of elasticity is the slope of the stress-strain diagram at any point. Secant modulus of elasticity is stress divided by strain at any given value of stress or strain. It also is called stress-strain ratio.
Tangent and secant modulus of elasticity are equal, up to the proportional limit of a material. Depending on the type of loading represented by the stress-strain diagram, modulus of elasticity may be reported as: compressive modulus of elasticity (or modulus of elasticity in compression); flexural modulus of elasticity (or modulus of elasticity in flexure); shear modulus of elasticity (or modulus of elasticity in shear); tensile modulus of elasticity (or modulus of elasticity in tension); or torsional modulus of elasticity (or modulus of elasticity in torsion). Modulus of elasticity may be determined by dynamic testing, where it can be derived from complex modulus. Modulus used alone generally refers to tensile modulus of elasticity. Shear modulus is almost always equal to torsional modulus and both are called modulus of rigidity. Moduli of elasticity in tension and compression are approximately equal and are known as Young's modulus. Modulus of rigidity is related to Young's modulus by the equation:
where E is Young's modulus (psi), G is modulus of rigidity (psi) and r is Poisson's ratio. Modulus of elasticity also is called elastic modulus and coefficient of elasticity.
Modulus of Resiliency The energy that can be absorbed per unit volume without creating a permanent distortion.
Modulus of Rigidity Rate of change of strain as a function of stress in a specimen subjected to shear or torsion loading. It is the modulus of elasticity determined in a torsion test. Alternate terms are modulus of elasticity in torsion and modulus of elasticity in shear. Apparent modulus of rigidity is a measure of the stiffness of plastics measured in a torsion test (ASTM D-1043). It is "apparent" because the specimen may be deflected past its proportional limit and the value calculated may not represent the true modulus of elasticity within the elastic limit of the material.
Modulus of Rupture Measure of the ultimate strength determined in a flexure or torsion test. In a flexure test, modulus of rupture in bending is the maximum fiber stress at failure. In a torsion test, modulus of rupture in torsion is the maximum shear stress in the extreme fiber of a circular member at failure. Alternate terms are flexural strength and torsional strength.
Modulus of Toughness The work done on a unit volume of material as a simple tensile force is gradually increased from zero to the value causing rupture is defined as the Modulus of Toughness. This may be calculated as the entire area under the stress-strain curve from the origin to rupture. Toughness of a material is its ability to absorb energy in the plastic range of the material.
Molecule The smallest unit quantity of matter that can exist by itself with characteristic properties.
Moment A twisting action; a torque; a force acting at a distance from a point in a structure so as to cause a tendency of the structure to rotate about that point. See also bending moment, moment connection.
Moment Connection A connection between two structural members that is highly resistant to rotation between the members, as differentiated from a shear connection, which allows rotation.
Moment of Inertia The rotational analog of mass. The sum of the products of mass and the square of the perpendicular distance to the axis of rotation of each particle in a body rotating about an axis.
Moments of Inertia, Properties of Sections
Mortar A substance used to join masonry units, consisting of cementitious materials, fine aggregate, and water.
Moving Compression Thrust.
Multifunctional materials and structures Materials and structures with more than one operating function. Examples include structures that serve thermal management, self- or external assessment, self-repair, and self-actuation functions. A specific example would be the use of active embedded layers for vibration damping in helicopter rotor blades.
Multi-layered/monolayered A multi-layered material or structure is composed of more than one layer, such as laminated composite materials and hierarchical structures. A monolayer is a monolithic laminate from which composite laminates are constructed; and a “single” layer of atoms or molecules absorbed or applied to a surface..
Necking Localized reduction of cross-sectional area of a specimen under tensile load. It is disregarded in calculating engineering stress but is taken into account in determining true stress.
Network Any combination of intersecting or interconnecting units, such as rods, bars, filaments, lines, passages, channels, etc.
Neutral Axis An axis of a figure, a circle or a sphere, which is indistinct from any other axis of the figure; an imaginary line in the cross section of a beam, shaft, or the like along which no stresses occur.
Nominal stress Stress calculated on the basis of the net cross section of a specimen without taking into account the effect of geometric discontinuities such as holes, grooves, fillets, etc.
Nonaxial In a direction not parallel to the long axis of a structural member.
Nonlattice Irregular; without the symmetry of a lattice.
Non-loadbearing Not carrying a load.
Normal Perpendicular to the cross section of the part, i.e.: The force (P) produces stresses normal (i.e., perpendicular) to the cross section of the part.