A transducer for detecting a shaft dynamic behavior. The transducer comprises an arcuate sensor member supported between an inner member and an outer member. At least one strain gage is attached to a surface of the arcuate sensor member to detect a surface strain caused by a shaft dynamic behavior. The inner member, outer member and arcuate sensor member are substantially coplanar. The inner member comprises a means for attaching the transducer to a mounting surface. The inner member may also comprise a self-aligning feature to optimize a sensor sensitivity.