Design and Experimental Investigation of Four-Bar Dynamic Testing Machine

Abstract

This project involved fabricating and experimental investigation of a dynamic testing machine for four-bar mechanisms with various applications. The simple crank rocker inversion is selected, and the kinematic design of the four-bar mechanism is done by keeping in view the Grashof rotatability criteria and the dynamic design required factoring in the forces acting on various links. The flywheel is designed to minimize the fluctuations in the torque required to drive the mechanism. DE-ASME Elliptic criteria is used for the shaft design and selection of bearing. For transmitting power from the AC motor to the crankshaft, a V belt and a pulley are used as the belt helps dampen the vibration effects in the mechanism. The linkages were fabricated, and the mechanism was assembled. ADXL335 accelerometer sensor is mounted on the apparatus to measure the acceleration of a point on the coupler. This acceleration data was then integrated using numerical techniques to estimate velocity and displacement. The model changes can be adjusted according to the dimensions of the bars and angles between the bars to simulate the performance of the mechanism. Due to the inherent offset in the sensor, an error was included in the data. However, the results obtained using such methods were satisfactory in visualizing the behaviour of data representing the system’s motion under running conditions. The errors in the result can be minimized using more advanced integration techniques and sensitive sensors for measurement and instrumentation. This research aims to contribute vital research knowledge for developing sustainable four-bar dynamic testing mechanisms.