The hardware of the system is built upon the general computer, including pulse hammer, electric charge amplifier, piezoelectricity sensor, A/D convertor etc;

In this paper, a pulse hammer method was used to carry out the modal test on a side wall of a Shanghai-50 gear-box, by which the modal parameters were identified.

The theoretical basis of pulse hammer excitation method used to detect the damage and measure the dynamic elastic modulus of solid wood flooring is briefly explained. The method is then examined by finite element simulation test.

The results show that pulse hammer excitation can be used to effectively measure the natural frequency values and dynamic elastic modulus of solid wood flooring,and the latter is bigger than the static elastic modulus.

In this paper, a pulse hammer method was used to carry out the modal test on a side wall of a Shanghai-50 gear-box, by which the modal parameters were identified. Thus, the side wall was simplified as a vibration system with fourteen degrees of freedom. And the vibratioa equation set was established and solved according to single degree of freedom system under modal coordinates. The calculated values of vibration velocity at fourteen points on the side wall were compared with those measured interfacial...

In this paper, a pulse hammer method was used to carry out the modal test on a side wall of a Shanghai-50 gear-box, by which the modal parameters were identified. Thus, the side wall was simplified as a vibration system with fourteen degrees of freedom. And the vibratioa equation set was established and solved according to single degree of freedom system under modal coordinates. The calculated values of vibration velocity at fourteen points on the side wall were compared with those measured interfacial noise levels and coincidence was found. Finally, the dynamic modification was taken on the side wall of the gearbox according to above vibration model. And the noise reduction value of 1.4 dB(A) was obtained.

This paper describes the application of a self-designed resistance-strain torquue transducer to test the torque change between the starting and idling of two type of induStrial sewing-machines.So as to illustrate the close relationship between the machin's starting torque and starting process,the paper indicates the inadequateness of the rule now adopted in the sewing-mechine trade, of using the resistance acquired merely by 2 rotations per minute operation condition for the sewing-machine's starting torque....

This paper describes the application of a self-designed resistance-strain torquue transducer to test the torque change between the starting and idling of two type of induStrial sewing-machines.So as to illustrate the close relationship between the machin's starting torque and starting process,the paper indicates the inadequateness of the rule now adopted in the sewing-mechine trade, of using the resistance acquired merely by 2 rotations per minute operation condition for the sewing-machine's starting torque. The peper also bets with the use of pulse (hammer)-activation method and dynamic characteristic (natural frequency) of industrial sewing-meching,and to determine the magnitudes of acceleration and amplitude,etc,in idle running,thereby offering an approach,and the concrete measures for the manufacturers to improve the quality of their products.

The theoretical basis of pulse hammer excitation method used to detect the damage and measure the dynamic elastic modulus of solid wood flooring is briefly explained. The method is then examined by finite element simulation test. The results show that pulse hammer excitation can be used to effectively measure the natural frequency values and dynamic elastic modulus of solid wood flooring,and the latter is bigger than the static elastic modulus. It is also found that the detecting point should be...

The theoretical basis of pulse hammer excitation method used to detect the damage and measure the dynamic elastic modulus of solid wood flooring is briefly explained. The method is then examined by finite element simulation test. The results show that pulse hammer excitation can be used to effectively measure the natural frequency values and dynamic elastic modulus of solid wood flooring,and the latter is bigger than the static elastic modulus. It is also found that the detecting point should be at or near the maximum amplitude of main vibration frequency while the impacting point should be at the greater amplitude and far from the detecting point. Finally,it is concluded that solid wood flooring damage can be detected precisely by using natural frequency values.