Design of the mounting system of a grass trimmer engine for minimum handle vibration response based on frequency-dependent stiffness and loss factor properties

The vibration in the rolling axis of a grass trimmer contributes to the hand arm vibration at its handle. One method to reduce the handle vibration of this engine is by attenuating the engine rolling vibration using an optimum layout of the engine mounts. Using the frequency-dependent stiffness and loss factor properties of the rubber mount, a new design of a four-point mounting system is investigated and analysed. Optimisation of the rolling vibration, based on the design parameters of the mount location and orientation, are carried out. The optimised system exhibits a rolling vibration acceleration reduction of 73 %. The new optimum design of the engine mounting system is fabricated and installed in the grass trimmer to validate the solution, and the results showed 75 % reduction of the measured angular acceleration transmissibility from the engine to the handle.