Glossary

Bake: Baking takes the result of solid analysis and converts the solid into a surface mesh for further downstream processes. See the section on Bake Deformed Geometry for a description of baking options supported in Scan&Solve™.

Body load: Force acting on every volumetric portion of the body. Gravitional force (weight) is a common example of a body load. See the section on Body Loads for a description of body loads supported in Scan&Solve™.

Brittle (material): tends to fail under tensile stress without significant deformation. Brittle materials include pottery, concrete, ceramics, glass, cast iron, and some polymers. Some ductile materials could also become brittle at low temperature.

Coulomb-Mohr (failure criterion): used for brittle materials, more conservative than Rankine criterion.

Danger level: The danger level, for a specific failure criterion, is a scalar value that ranges between 0 and 1. It is computed at every point as a ratio of the computed value of the selected failure criterion to the threshold value known to cause failure of this particular material. The value greater than 1, indicates that the computed value exceeds the known threshold.

Deflection: is a visualization of the computed deformation in the body. It is constructed by magnifying the magnitude of displacement at every point by thousands of times. It should not be confused with the actual physical deformation of the body.

Deformation: A body deforms because different points of the body have different displacements. If all displacements were the same, the body would move rather than deform. The rate of deformation at a point is measured by strain.

Displacement: is a vector (x-, y-, z-) quantity measuring where each point of the body moves after the loads are applied. Total displacement is a (scalar) magnitude of the displacement vector. Displacement is measured in units of length.

Ductile (material): exhibits the ability to deform (stretch) under tensile stress without fracture. Ductile materials include gold, copper, steel, aluminum, rubber, and other stretchable materials.

Failure criterion: is an estimation of the failure of a component or a structural member based on the stress state. Components constructed from ductile materials are assumed to fail when they undergo plastic deformation. The von Mises criterion is commonly used to estimate this type of failure. Failure in brittle materials is sudden, with little or no plastic deformation. The maximum normal stress criterion or Mohr's theory are used to predict brittle failure.

Homogeneous (material): the same at every point of a body.

Isotropic (material): the same in all directions.

Linear (model): the output (response, e.g. deformations) of a system increases or decreases in direct proportion to the input (e.g. loads). If the input is doubled in size, the output is doubled too.

Modified Mohr (failure criterion): used for brittle materials, more conservative than Coulomb Mohr criterion.

Normal stress (strain): component of stress (strain) measured in the direction normal to a specified plane or surface.

Principal stress (strain): at any location in a body, it is possible to orient the coordinate system in such a way that shear stresses (strains) vanish in all directions and only normal stresses acting in the three orthogonal coordinate axes directions remain. These three components of stress are called principal stresses (strains). The value and the direction of the principal stresses (strains) changes at every point.

Rankine (failure criterion): used for brittle materials, it is also known as maximum normal stress criterion because it predicts failure of brittle materials based on the maximum value of principal stress.

Resolution: maximum number of finite elements used to compute an approximate solution of the stress analysis problem. Only those elements that intersect the solid are included in the count. Higher resolution requires more memory and longer computation times.

Restraint: geometric condition or constraint applied to the boundary of a solid. Restraints specify that selected boundaries cannot move when external loads are applied. Individual restraints may be complete (in all directions) or partial (in some directions), but combined restraints must prevent body from moving in order to solve the structural analysis problem. See the section on Restraints for restraints supported in Scan&Solve™.

Shear stress (strain): component of stress (strain) measured tangentially to the indicated direction.

Solid (in Rhino): a closed solid poly-surface in Rhino's jargon. More precisely, a solid is bounded by a collection of NURBs surfaces that intersect only on their bounding edges, and every edge is shared by exactly two surfaces.

Static: dynamic (time-varying) effects are ignored. Static forces are applied very slowly and do not change once they reach their full magnitude.

Surface load: Force applied to applied to a boundary of the solid. See the section on Surface Loads for a description of surface loads supported in Scan&Solve™.

Strain: informally, strain measures (directional) rate of deformation within the body. It is dimensionless because it measures change of length per unit length. Just like stress, one-dimesional strain can be measured in any direction, and there is one-to-one correspondence between components of stress and strain (normal, shear, principal, etc.)

Stress: describes all forces acting at a point in a body. Different forces act in different directions. For any selected direction, stress in that direction is measured as a force acting across an imaginary plane perpendicular to the selected direction. The force component normal to the plane is called normal stress; the force component tangential to the plane is called shear stress. This process may be repeated for every direction, but it is enough to represent tangential and normal stresses for the 3 coordinate planes. These six components of stress are measured in units of Force/Area.

Torque: Also called moment of force, measures the rotational effect of force applied about some axis a distance away. It is measured in units of Force x Length.

Von Mises (failure criterion): The von Mises criterion (also called Von Mises stress) is a scalar quantity calculated from stress components that measures distortion energy and is used to predict failure of ductile materials.