จำนวน Repository ( 9 )
รูปแบบล้อ Run-flat ที่เหมาะสมสำหรับรถยนต์บรรทุกปกติขนาดเล็กติดเกราะ
The objectives of this research were to study the stress intensity in run-flat metal wheels and to design a new type of run-flat wheels that can be used in a small armored regular truck. Experimental methods and finite element methodologies were applied in the research process. The results obtained by comparing the strain values from the two methods demonstrated the consistency of both methods. The differences in stress values were in 10 -16 percentages which could confirm the capability to analyze the stress distribution and deformation of run-flat by a finite element method. Proven processes and procedures in Pre-processing with SolidWorks Simulation were utilized to design run-flat wheels and a reverse engineering process was next used to create wheel rims and design the cross-sectional shape of new run-flat wheels made of composite materials which have an important reactant; a polymer group and aluminum oxide powder added to enhance the strength. The designed parameters consisted of 1) the width of the run-flat wheels 2) the internal and external radius in which the internal radius depending on the size of the wheel rim and the outer radius which is a variable that determines the height of the run-flat wheels 3) the design of a lockset for tightening the run flat wheels to the wheel rims 4) materials used in the structure of the run-flat wheels and 5) tire pressure. The run-flat wheels designed and built into three-piece parts were designed for ease of wheel assembly or disassembly out of the wheel rims. By analyzing the intensity of stress accumulated in a conventional run-flat wheel (run-flat metal wheel) the stress generated in a run-flat wheel did not exceed the limit of the Yield stress and had a safety value between 3-5 times for new run flat wheels with a maximum stress of 26 MPa. Sizing and cross-sectional dimensions of run flat wheels thus resulted in stress which was in the range that could be withstood and acceptably employed. It was also possible to reduce the height of the flat wheels to make the rear flats lower and increase the width of the run flat wheels which would help distribute more weight to the wheel rims.
การวิเคราะห์มุมเอียงและความหนาของแผ่นเกราะที่มีผลกระทบต่อการต้านทานการเจาะทะลุของกระสุนบนแผ่นเกราะอลูมิเนียมและสแตนเลส ด้วยระเบียบวิธีไฟไนต์เอลิเมนต์
This thesis was an analysis of the significance of angle of inclination and the thickness of the armor plate on the penetration resistance of bullets on aluminum and stainless steel armor plates determined by the finite element method. In this study the information results obtained from actual firing of bulletproof armor and the finite element simulation according to NIJ 3 standards were compared to create a pattern of bulletproof and bulletproof armor using the SolidWorks program. The simulation model of the armor shooting was created by the Ansys/Explicit Dynamics program. The bullet material was 7.62 mm tungsten carbide (WC). There were three plate types used in the simulation were made of different bulletproof armor materials: 1) stainless steel SUS304 using for the plate thickness of 5 6 8 10 14 20 30 40 45 and 55 mm. 2) aluminum AL7075 using for the plate thicknesses of 6 8 10 and 20 mm. Additionally 3) tungsten carbide using for the plate thicknesses of 6 8 and 10 mm. Each of these plates had a width x length of 300 x 300 mm. The simulation models were divided into two types: Type 1 a simulation firing at one plate at a time. Type II a simulation firing at two layered plates stacked together without any gaps between plates. The front and the back plates made of stainless steel and aluminum respectively or tungsten carbide and stainless steel respectively were determined. The angles of firing at bulletproof armor were set at 0 30 and 45 degrees. The output results were that in Type I the stainless-steel plate with a thickness of 30 mm or more could resist the penetration of bullets. However in Type II 2 stacked layers of the armor plates using the front stainless plate with a thickness of only 20 mm and the back aluminum plate with a thickness of only 8 mm could provide the same constructive results as those of tungsten carbide and stainless steel plates for the front and back plates with both thickness setting at 16 mm. All of them showed the resistance of the penetration to the bullets. More observation was that the increases in angles as a result enhanced more resistance of the bulletproof plates to bullet penetration.
แผ่นเกราะโลหะกันกระสุน
This research project aimed to analyze and design the pattern of a bulletproof metal armor plate as well as build a bulletproof metal armor plate for a small armored regular truck. The methodology consisted of the NIJ standard test and the finite element analysis. The bulletproof plates created were tested for a real firing. Their firing results were compared with those of NIJ-standard using a finite element program in this case applying with the program Ansys/Explicit Dynamic. SolidWorks program is employed as a tool to design and create 3D models of armor plates and bullets. The materials taken in the finite element simulation were SKD11 and SUS304 and the parameters utilized in the research were material types hardness values spacing between the plates and thickness. In the case of two armor plates stacked SKD11 material was designed for the first armor plate to be hit by the bullet. It served to destroy bullets. In addition the second armor plate made of SUS304 material served to absorb energy and obstruct the movement of bullets. For testing a 30-06 caliber M2 AP 166 Gr bullet was selected at a 0-degree angle and the velocities measured and set by the Ansys/Explicit Dynamic program were 901.7 m/s and 880 m/s respectively. The front plate made of SKD11 material with a thickness of 10 mm and the back plate made of SUS304 material with a thickness of 10 mm were fired 1 shot. The results showed that the bullet could penetrate the front armor plate but not penetrate the back-armor plate. In the NIJ 3 standard tests the shooting with a 7.62x51 mm NATO FMJ 148 Gr shell at a 0-degree angle for 5 times with velocities equal to 846.4 841.3 839.1 838.2 and 845.3 m/s was performed on the stacking front and back armor plates both made of SUS304 material with a thickness of 8 mm. The bullet velocity simulated by the Ansys program was 847 m/s resulting in the front plate having a bullet penetration and a slight bulge on the back plate. From the finite element simulation results and the actual test results it was found that the damage to the armor plates detected by both methods was consistent. Therefore the finite element program was selected to simulate the damage of armor plates resistant to penetration according to the NIJ standard Level 4. The results of the research could be concluded that the use of armor plates stacked with suitable different materials in multiple layers would affect the penetration resistance. Increased thickness and optimal spacing between the armor plates were important parameters in penetration resistance. Moreover it revealed that the higher the material hardness the better its ability to resist penetration. In particular this suggestion should be applied to the first armor plate or front armor plate.
การศึกษาพารามิเตอร์ในการขึ้นรูปแผ่นเกราะเซรามิกส์รูปร่างหกเหลี่ยมกันกระสุน
This research had two objectives that were to study parameters for forming bulletproof ceramic armor plates and to create a model of a bulletproof ceramic armor plate for small armored regular trucks. The parameters used to form a ceramic armor plate contain the thickness of the armor plate and the compressive strength which affects the density distribution of the green compact. A ballistic ceramic armor plate with a hexagonal shaped material was created as a concave bulletproof plate. Extrusion results displayed that the hexagonal material was formed at a very high density on the side surface of the armor plate but with uneven capacity distributed across the overall plate due to the friction occurring on the wall of the mold. The finite element method particularly at the Ansys/Explicit Dynamic tools were applied to analyse the damage of bulletproof plates. The model of a concave-shaped bulletproof plate was set for the SKD11material influencing the changes in the direction of the bullet firing when the bullet hit the bulletproof plate at a velocity of 880 m/s in accordance with the NIJ 4 standard. The bullet was made of tungsten carbide and the ceramic armor plate was built with a size of 300×300 mm and thicknesses of 14 16 18 and 20 mm. The bullet was fired into the center part and onto the curved surface of the ceramic plate. The result shows that the armor plate could not resistant to penetration. In this situation the direction of the bullets movement against the armor plate especially at a curved surface as a slope could result the deflection of the bullet direction as well as reduction of penetration capability.
Finite element analysis of armor piercing bullet penetrating hard steel
The bulletproof plates with materials that can convincingly be destroyed by the 7.62 mm bullet with its speed at 878 ± 9.1 m/s were developed by designing according to the National Institute of Justice Level 4 (NIJ 4). The plates were made of two flat sheets stacking SKD11 and SUS304. Their components were composed of the front and back plates; the first sheet made of SKD11 material hardening at 65 HRC with a thickness of 6 mm and the back plate made of SUS 304 material with a thickness of 5 mm. The finite element method was applied to simulate and analyze the results to demonstrate the bullet resistance to the perforation by setting perpendicular sheet to the bullets. Therefore the simulating studies for the bullet firing were demonstrated by locating its angles of 15 30 45 and 60 degrees to the SKD11 sheet with a thickness of 6 8 and10 mm coupled with the SUS304 sheet with a thickness of 5 6 8 and 10 mm. These plates were stacking into two layers then the finite element method was applied to simulate one at a time. The results showed that the first sheet of SKD11 with 6 mm of thickness could resist the perforation of the bullet at 60 degree and the plate thickness of 8 and 10 mm could start resisting to the perforation at 45 degree. The second sheet of SUS304 with the thickness of 5 6 8 and 10 mm were incapable to resist to the perforation and the refraction of the bullet direction as good as that of SKD11. Therefore the principle applying two metal sheets stacked into layers was essential to impel the resistance of the bullet perforation and change the direction of the bullet.