What is the function of a lock washer in a bolted connection?

A lock washer is specifically designed to prevent loosening of a bolted connection due to vibration. When a bolt is tightened, the lock washer exerts a spring-like force, which creates additional friction between the washer and the nut or bolt head. This friction helps to resist the rotational movement that might occur if the assembly is subjected to vibration or other dynamic loads. As a result, using a lock washer is a common practice in situations where bolted connections experience significant movement or vibrations, ensuring that the assembly remains secure over time.

The other options do not accurately describe the primary role of a lock washer. While holding the joint in place and enhancing load distribution are important aspects of a bolted connection, these functions are better addressed by the primary fastener itself. Additionally, providing a decorative finish is not a functional aspect of lock washers; they are primarily utilized for their mechanical properties rather than aesthetic purposes.