Several smart materials such as shape memory alloys (SMA) and electroactive polymers (EAP) have good properties in small scales and are often a good choice for tiny surface deflection applications. However they need continuous powering to keep their shape change, leading to a significant loss of energy. An interesting approach is to associate a smart material with a bistable element, which provides two stable positions without power. This action requires some energy to snap from one position to the other one. This association gives a very power-efficient solution. In this paper, we present a mechanical study on the actuation of a bistable structure, using a distributed torque actuation that is very suitable for smart materials. We provide an approach to optimize the actuation location, this allow to use less powerful and more compact actuators.