Academia.eduAcademia.edu

Figure 4 – uploaded by Milan Ivković

See full PDFdownloadDownload figure
In order to satisfy the basic principles of the finite element method based on continuum mechanics, with the use of available tools in the software, the existing model was simplified, and the weld zones were approximated by transitional zones and continuous joints at the welding points of the central part and sides of the carriage, Fig.4 [9]. At the same time, care was taken to ensure that the dimensions of the models remain unchanged. Figure 4. Display of the model of the middle surfaces of the structure of the upper carriage in the software package FEMAP.

Figure 4 In order to satisfy the basic principles of the finite element method based on continuum mechanics, with the use of available tools in the software, the existing model was simplified, and the weld zones were approximated by transitional zones and continuous joints at the welding points of the central part and sides of the carriage, Fig.4 [9]. At the same time, care was taken to ensure that the dimensions of the models remain unchanged. Figure 4. Display of the model of the middle surfaces of the structure of the upper carriage in the software package FEMAP.

Related Figures (9)

During the firing action, the gun carriage is loaded with a recoil force, R, at an elevation angle, a, by the weight of the system, G, and at the place where the is pivot , reactions of connections Fa and Fb occur . From the conditions of the balance of forces in the system, we obtain the reactions on analytical way, which we will be confirmed with numerical analysis. Figure 1. Schematic representation of the forces acting on the upper carriage during firing
During the firing action, the gun carriage is loaded with a recoil force, R, at an elevation angle, a, by the weight of the system, G, and at the place where the is pivot , reactions of connections Fa and Fb occur . From the conditions of the balance of forces in the system, we obtain the reactions on analytical way, which we will be confirmed with numerical analysis. Figure 1. Schematic representation of the forces acting on the upper carriage during firing
Table 1. Construction parameters of automatic grenade launcher BGA 30 mm M93 [1 Based on the geometric dependence of the positions of the arms cradle supports, the center of gravity of the weapon, the axis of the barrel channel (the place where the force of the gunpowder gases acts) and the position of the pivot, a schematic representation of the forces given in Fig.l was created. For these conditions, the equations of stability and loading of the upper carriage are derived.
Table 1. Construction parameters of automatic grenade launcher BGA 30 mm M93 [1 Based on the geometric dependence of the positions of the arms cradle supports, the center of gravity of the weapon, the axis of the barrel channel (the place where the force of the gunpowder gases acts) and the position of the pivot, a schematic representation of the forces given in Fig.l was created. For these conditions, the equations of stability and loading of the upper carriage are derived.
Figure 3. Components of the recoil resistance force and the total recoil resistance force [6] Bolt braking mechanisms have the role of transforming a short-term, but large impulse of recoil force IT into a long- term impulse of resistance force IR, which is significantly smaller. Fig.2 shows a graphical representation of the transformation diagram of the braking force.
Figure 3. Components of the recoil resistance force and the total recoil resistance force [6] Bolt braking mechanisms have the role of transforming a short-term, but large impulse of recoil force IT into a long- term impulse of resistance force IR, which is significantly smaller. Fig.2 shows a graphical representation of the transformation diagram of the braking force.
Figure 2. Diagram of recoil braking force [ ] The last part in equation (4.2.4) refers to the weight component of the recoil mass, which, when the barrel of the weapon is elevated by an angle a, reduces the effect of the recoil resistance force.
Figure 2. Diagram of recoil braking force [ ] The last part in equation (4.2.4) refers to the weight component of the recoil mass, which, when the barrel of the weapon is elevated by an angle a, reduces the effect of the recoil resistance force.
Figure 5. MKE upper carriage construction model represent the thin-walled construction created by bending and welding the corresponding plates and sheets [10,11]. The layout of the generated finite element mesh is shown in Fig.5.
Figure 5. MKE upper carriage construction model represent the thin-walled construction created by bending and welding the corresponding plates and sheets [10,11]. The layout of the generated finite element mesh is shown in Fig.5.
For the set analysis parameters and the generated finite element model, results were obtained for the effective (Von- Mises) stress fields of the upper carriage model under the action of dynamic load at different elevation angles a. Based on the load analysis of the upper carriage for different elevation angles, the changes in the values of the maximum stresses and deformations in the zones of the most loaded elements of the structure were monitored and were shown graphically depending on the time of the dynamic load (weapon firing) and the elevation angle.
For the set analysis parameters and the generated finite element model, results were obtained for the effective (Von- Mises) stress fields of the upper carriage model under the action of dynamic load at different elevation angles a. Based on the load analysis of the upper carriage for different elevation angles, the changes in the values of the maximum stresses and deformations in the zones of the most loaded elements of the structure were monitored and were shown graphically depending on the time of the dynamic load (weapon firing) and the elevation angle.
Figure 8. Display of the field of total displacements for mn elevation angle of 20°, time instant of 0.0125s
Figure 8. Display of the field of total displacements for mn elevation angle of 20°, time instant of 0.0125s
The effective stress field chosen for the critical case of loading the upper carriage, elevation angle (a= 20°), is shown in Fig.6, where the maximum value of the stress, when the load is applied, is 116.5 MPa, whil.7. Figure 7. Place of maximum (Von-Mises) stress of upper carriage for elevation angle (a= 20°), moment 0.0125s
The effective stress field chosen for the critical case of loading the upper carriage, elevation angle (a= 20°), is shown in Fig.6, where the maximum value of the stress, when the load is applied, is 116.5 MPa, whil.7. Figure 7. Place of maximum (Von-Mises) stress of upper carriage for elevation angle (a= 20°), moment 0.0125s
Figure 9. Graphic representation of the effective stress for the rib element of the structure depending on the time interval for different elevation angles.
Figure 9. Graphic representation of the effective stress for the rib element of the structure depending on the time interval for different elevation angles.
Related topics:
EngineeringScientific and Technical Translation
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved