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The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great significance to improve machining quality. In this paper, a workpiece and an actuator dynamics are considered in modeling and controller design. A proportional-integral controller (PI) is presented to control and actively damp the chatter vibration of a workpiece in the milling process. The controller is chosen on the basis of its highly stable output and a smaller amount of steady-state error. The controller is realized using analog operational amplifier circuit. The work has contributed to planning a novel approach that addresses the problem of chatter vibration in spite of technical hitches in modeling and controller design. The method can also lead to considerable reduction in vibrations and can be beneficial in industries in term of cost reduction and energy saving. The application of this method is verified using active damping device actuator (ADD) in the milling of steel.

A finite element method has been developed for modeling the characteristics of self-pierced rivets (SPR) in the aluminum parts and structures subjected to impact. It considers SPR elastic, inelastic and separation behaviors and was developed based on the coupon test results in lap shear, coach peel, and tension modes. The method consists of establishing baseline strength characteristics in the six degrees of freedom; and then modifying the baseline properties with coefficient factors (Ki) factors that influence the performance of SPR (thickness, differences in material, temperature, impact velocity, size of connection). The resulting combination is a material damage function that is utilized as the material properties of beam-type spring elements simulating the SPR connection in a FE model. The baseline properties and the equations for coefficient factors (Ki) developed in this study are provided. The material damage functions were developed in the RADIOSS environment, but can be applied to other codes as well. The method was validated at the component level using various configuration of a hat section tube. The CAE prediction using the new method correlates with the test results well in all the cases.