Infinitesimal and Finite Mechanisms

In the design of engineering structures, an important question is whether a structure is rigid. For conventional structures, rigidity is a fundamental requirement. However, there are cases where just the opposite is required. In order to answer the question of rigidity we have to know the static-kinematic properties of the structure. In the forthcoming, these properties will be investigated for bar-and-joint assemblies, that is, for structures composed of straight bars and frictionless pin joints. Firstly, we survey the basic terms to be used in the analysis.