| Inertial Force: | (english) A fictitious force used for convenience in visualizing the effects of forces on bodies in motion. For an accelerating body, the inertial force is considered as a body force whose resultant acts at the object's center of gravity in a direction opposite the acceleration. The magnitude of the force is the mass of the object times the magnitude of the acceleration. |
| Kinetic Energy: | (english) The energy of a moving mass; equal to (mv^2)2. Where m is mass and v is the magnitude of the velocity. |
| Linear: | (english) A structure is said to behave linearly when its the deformation response is directly proportional to the loading (i.e. doubling the load doubles the displacement response). For a material, linear means that the stress is directly proportional to the strain. |
| Line of Action: | (english) The line of action of a force is the infinite line defined by extending along the direction of the force from the point where the force acts. |
| Linear Elastic: | (english) A force-displacement relationship which is both linear and elastic. For a structure, this means the deformation is proportional to the loading, and deformations disappear on unloading. For a material, the concept is the same except strain substitutes for deformation, and stress substitutes for load. |
| Load: | (english) An external force. The term load is sometimes used to describe more general actions such as temperature differentials or movements such as foundation settlements. |
| Modulus of elasticity: | (english) The proportional constant between stress and strain for material with linear elastic behavior: calculated as stress divided by strain. Modulus of elasticity can be interpreted as the slope of the stress-strain graph. It is usually denoted as E, sometimes known as Young's Modulus Y, or E-Modulus. |
| Moment of inertia (I): | (english) Moment of inertia has two distinct but related meanings: 1) it is a property of a an object relating to the magnitude of the moment required to rotate the object and overcome its inertia. 2) A property of a two dimensional cross section shape with respect to an axis, usually an axis through the centroid of the shape. |
| Normal stress: | (english) Stress acting perpendicular to an imaginary plane cutting through an object. Normal stress has two senses: compression and tension. Normal stress is often simply called stress. |
| Pin connection: | (english) In two dimensions, a pin connection restrains two translation degrees of freedom but does not restrain rotation. Since the rotation degree of freedom is unrestrained at a pin connection, it transfers no moment. |