Voimaemenetelmä

Voimaemenetelmä, often translated as the "force method" or "stiffness method" in English, is a fundamental concept in structural analysis used to determine the internal forces and displacements within a structure. It is one of the two primary approaches, alongside the displacement method, for solving indeterminate structures. The core idea behind the force method is to treat unknown support reactions or internal forces as redundants.

The process begins by identifying and releasing these redundant forces, transforming the original indeterminate structure into a statically determinate one. This determinate structure is then analyzed under the influence of external loads. Subsequently, the redundant forces are reintroduced, and their magnitudes are determined by ensuring that the compatibility conditions of the original structure are satisfied. These compatibility conditions typically relate to displacements and rotations at the points where the redundants were released.

The mathematical formulation of the force method often involves the use of flexibility coefficients, which relate displacements to applied forces. The equilibrium equations are straightforward, but the compatibility equations can become complex, especially for large structures. While conceptually important and providing a deep understanding of structural behavior, the manual application of the force method can be tedious. However, it remains a valuable tool for understanding the principles of structural analysis and is often implemented in structural analysis software.