The structural relaxation of a cluster containing 55 atoms at elevated temperatures is simulated by molecular dynamics. The interatomic interactions are given by using the embedded atom method (EAM) potential. By decomposing the peaks of the radial distribution functions (RDFs) according to the pair analysis technique, the local structural pattes are identified for this cluster. During increasing temperature, structural changes of different shells determined by atom density profiles result in an abrupt increase in inteal energy. The simulations show how local structural changes can strongly cause inteal energy to change accordingly.