Abstract: A reciprocating compressor, being small-sized and compact, for compressing hydrogen gas to be used in a fuel-cell car, has a crankshaft, to which an end of a connecting rod is connected. The other end of the connecting rod is connected to a crosshead. To the crosshead are connected a pair of shafts, each extending in directions opposing to each other. To each of the shafts is connected a plunger. The each plunger is received within a cylinder at the tip portion thereof. A pair of plungers moves reciprocally on an almost same axis, and the crosshead is formed in one body.

Abstract: In a hybrid vibration experiment of the structure, while shaking an actual model simulating a portion of the structure, analysis is made on vibration response of a numerical model simulating the remaining portions of the structure, with using a computer. Loading members are provided neighboring to the actual model. The plural numbers of vibrators vibrates the actual model through the loading member. A control means for the vibrators controls the plural numbers of vibrators, so that not a point displacement, but a distributed displacement is loaded on the actual model.