Research On Piezoelectric Dynamometer With Tangential Load-distribution

With the rapid development of modern science and technology, the piezoelectric measuring technology is used more widely in the static and dynamic force test system. In recent years, there have been some new load-distribution test requirements in some case, The force in some direction which need to test exceed the sensor range, and the forces or torques in the other direction in the sensor are within the range of the sensor. For example, in high aircraft model aerodynamic force measuring project of some research center, two tangential forces value are beyond the range of the sensor and the normal force value is within the range of the sensor, then the tradition load-distribution method is improper.So it is very meaningful to seek a method where tangential force is load-distribution and normal force is not load-distribution.The paper do some research on piezoelectric dynamometer with tangential load-distribution on the basis of previous studies about load-distribution. This dynamometer can achieve tangential big load-distribution and normal small load-distribution, the research achievement has broad application space.The paper proposes a method of using expansion pins to achieve the load-distribution of dynamometer after analyzing the traditional piezoelectric dynamometer’s structure. At the same time, it designs the key parts’ structure of the dynamometer, in order to obtain the overall structure of the dynamometer. The paper does the dynamometer modal analysis with ANSYS Workbench to get the first six natural frequencies. It deduces the load-distribution ratio formula of tangential after studying the load-distribution principle of tangential with the help of mechanics of materials. The paper does static structural analysis of the dynamometer and gets different load-distribution ratio in case of different combinations of expansion pins. Besides, the paper discusses the factors affecting the tangential load-distribution, proves geometric parameters of expansion pins (mainly diameter and elastic modulus) have some impact on the tangential load-distribution ratio.The paper carries out the three-axis load-distribution tests and finds the static performance of dynamometer is good under pin expansion different arrangements, the load-distribution ratios in case of different combinations of expansion pins are different, the effect of expansion pins to tangential load-distribution is much greater than normal. The paper compares the results of theory and experiment to find the reasons of errors generate and proves the rationality of the design of the device by test. Subsequently, we carried out three-axis stiffness tests and natural frequency calibration tests, obtain stiffness values and the first natural frequency value under different circumstances and compare them. The conclusion of test proves that different combinations expansion pins have a certain degree of influence, and the degree of effect is consistent with that of load-distribution ratio.