Study on the measuring method of moving time in the bore of projectile for vibration analysis

The movement time of the projectile is the basic parameter for studying the gesture of the projectile. It is also the time base for the test of projectile shots. At the same time it is the time base for the test of gun vibration response. A test method for the moving time in the bore of a projectile which is based on the barrel strain test is proposed in this paper. First, paste a plurality of strain gauges along the axis of the barrel. Then take the rising edge time of the strain-time curve of each measuring point as the movement time of the Projectile. The artillery fired and the projectile moved at high speed inside. By testing the external surface strain time curve, and then through data processing, the time of a large-caliber artillery projectile in orbit was obtained. Through the firing test in the shooting range, the validity and correctness of the method are verified

Research on vibration displacement test method for large-caliber artillery muzzle

In order to solve the problem of muzzle vibration displacement test of large caliber under high elevation, this paper presents a test method by two high-speed photography. The method fully considers the influence of the muzzle torsion on the measurement results, and accurately obtains the three-dimensional vibration displacement of the muzzle of the large caliber artillery. Finally, through the result analysis, the accuracy of the measurement results can reach 0.1 mm, which shows the advantage of the sub-pixel-based high-speed camera processing method in the muzzle vibration displacement test of the conventional artillery. This paper proposes an innovative test method that accurately measures the vibration displacement of the muzzle using a non-contact method

An experimental study of the natural characteristics of the wheeled and the tracked self-propelled guns

With wheeled and tracked self-propelled guns as research object, the study carries out the experimental modal analysis by using traditional method of hammering and operational modal analysis method, and obtains low-order natural frequency of the guns, and thus lays the foundation for further research on the vibration characteristics of wheeled and tracked self-propelled guns. By contrasting the low-order natural characteristics of wheeled and tracked self-propelled guns, conclusions can draw as the following: the modal shapes (from low to high) of wheeled and tracked self-propelled guns are pitch, translation and roll; when the modal shapes are identical, the natural frequency of tracked self-propelled guns is greater than that of wheeled self-propelled guns, which accords with the test results of the gun’s suspension equivalent stiffness; for wheeled self-propelled guns, an accurate measure of the gun’s natural characteristics is feasible by either the traditional or the operational modal analysis method. When it comes to tracked self-propelled guns, the operational modal analysis method is more accurate

Study on measuring method of the angular displacement of muzzle vibration for the small caliber gun

In order to solving the key technique of the angular displacement of muzzle vibration for the small caliber gun, a measuring method of double eddy current displacement sensors for the angular displacement of muzzle vibration is proposed. Two sensors are installed at the measuring points which are distributed near the muzzle. Then, by the triangle transformation method, the vertical and horizontal linear displacement of the muzzle vibration can be transformed to the vertical and horizontal angular displacement. It has been verified by the firing test that the method is non-contact and has the capability of anti-muzzle-flash and anti-shock, and that the test accuracy can meet the requirement of the gun firing environment. By this method, the law of the angular displacement of muzzle vibration under three running firing is obtained during the process that after projectile exit, about three circles of attenuation vibration for the muzzle happen, and then the next projectile begins to leave the muzzle. It shows that the average value of the angular displacement of muzzle vibration is 1.93 minute in azimuth and 1.42 minute in elevation

A certain rubber shock absorber’s dynamic response research under impulse load

The complex impulse environment of artillery firing process brings very tough impulse resistance requirement for the artillery carrier equipment. The results of the vibration test of an electrical control box with a certain rubber shock absorber show that good shock absorb effect has not been received. Based on carefully theoretical analysis and simulation, it can be sure that the rigid collision when shock absorber reaches its limit is the reason. From the point of view of the theory and simulation of the experimental results, the analysis of the experiment results is given, which can provide the necessary theoretical basis of how to choose the appropriate shock absorber

Study on penetration characteristics of honeycomb aluminum

In order to analyze the mechanical properties of projectile penetrating honeycomb aluminum, a dynamic nonlinear finite element model of projectile penetrating honeycomb aluminum was established and verified by experiments. It is found that the numerical simulation results of projectile penetration into honeycomb aluminum are consistent with the acceleration variation of the test. When the projectile penetrates into the honeycomb aluminum, the acceleration waveform is trapezoidal and the peak and pulse width of the acceleration are related to the velocity of the projectile and the wall thickness of the honeycomb aluminum material. With the increase of the velocity of the projectile, the peak value of the acceleration increases and the pulse width of the acceleration decreases. With the increase of the wall thickness of honeycomb aluminum, the peak value of acceleration increases, while the pulse width of acceleration decreases

Study on dynamic characteristic of closed-cell aluminum foam

Closed-cell aluminum foam has been widely used in aerospace, rail transit and mechanical for its outstanding performance. But for a long time, the research on its vibration damping performance is only limited to the material damping test, there are relatively few studies on its dynamic characteristics. In this paper, we studied the relationship between dynamic characteristic and feature parameters. Modal assurance criterion and Finite element method were used to verify the accuracy of experimental model. It turned out that the average pore diameter of closed-cell aluminum foam conforms to Gaussian distribution. The modal analysis method can be used in the research of dynamic characteristic of closed-cell aluminum foam. Its damping ratio showed increasing trend with the increase of porosity, natural frequency and the decrease of mean pore size. Each order natural frequency increases along with the increase of porosity

Research on measuring method of the angular displacement of muzzle vibration

The angular displacement of the muzzle vibration has importance influence on the firing dispersion of gun. In order to solve the measuring problem on the angular displacement of the muzzle vibration in firing environment, a kind of measuring method of the angular displacement of the muzzle vibration based on the laser and the triangle principle was presented, and its measuring system was developed. The laser beam was sent by a laser. After the laser beam was reflected by a reflector on muzzle, the reflective beam was received by the position sensitive detector (PSD). Combining the optical distance parameter and the triangle relation, the angular displacement of the muzzle vibration could be obtained. The measuring error analysis of the system and the verification of the firing environment in shooting range were made. The performances of the measuring system were that the measuring range of the angular displacement was ±35', its angle resolution was 0.1', its relative errors under the different illumination conditions were less than 2 %. The measuring system can meet the needs of the gun measurement

Dynamic response analysis of the rubber shock absorber in the artillery vibration system

The complex impulse environment of the artillery firing process brings very tough vibration attenuation requirement of the artillery-mounted equipment. The experiment is designed to decrease an artillery mounted instrument container’s vibration. However, after being equipped with a certain rubber shock absorber, the vibration of this instrument container wasn’t being controlled. Thus, based on the theoretical analysis and dynamic simulation, we summarized that this phenomenon was caused by the rigid collision between two parts of the rubber shock absorber while reaching elastic limit. The result provides the necessary theory of choosing the appropriate artillery shock absorber. By using the Genetic Algorithm optimization design method, we found the best independent variable H

Simulation and experimental investigation of high-speed projectile impacting closed-cell aluminum foam

In order to analyze the impact acceleration of the projectile impacting the aluminum foam material, a dynamic non-linear finite element model of the projectile impacting the closed-cell aluminum foam experiment device was established and verified by the experiment. It is found that the numerical simulation results of projectile impact closed-cell aluminum foam are consistent with the change of experimental results. When the projectile impacts the homogeneous closed-cell aluminum foam, the impact acceleration is trapezoidal and the impact peak and pulse width are related to the density of the aluminum foam material. With the increase of the porosity of the aluminum foam, the peak value of the acceleration rises and the pulse width of acceleration decreases