จำนวน Repository ( 11 )
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.
สมบัติทางกลของพอลิเอทิลีนน้ำหนักโมเลกุลสูงยิ่งยวดเชิงประกอบด้วยอลูมิเนียมออกไซด์สำหรับการใช้งานทางวิศวกรรม
In conducting the research on Material Science two composite materials ultra high molecular weight polyethylene (UHMWPE) powder and aluminum oxide (Al2O3) powder were formulated by hot compression molding process. The formulated materials demonstrated good mechanical properties and high wear resistance properties. Based on the studies the Al2O3 grade selected was Al2O3 HTM 30 harboring mixed uneven powder particle sizes ranging from 2 to 5 microns (μm) and selected proportion of Al2O3 alloy mixed for improving mechanical and wear resistance properties of the UHMWPE composite material was the UHMWPE+Al2O3 HTM 30 at a ratio of 95:5%. When considering both material properties and cost effectiveness in the impact test 2-5 μm Al2O3 HTM carried the higher impact strength than other aluminum oxide grades with the values up to 586.8 J/m at a ratio of 5% aluminum oxide. The hardness test of the 2-5 μm UHMWPE+ Al2O3 HTM delivered the hardness at 58.8 using the standard durometer. The tensile test values consisted of Yield Strength Ultimate Tensile Strength Breaking Strength Elongation at Break and Modulus of elasticity equal to 20.52 MPa 29.96 MPa 22.83 MPa 265.8% and 784.46 MPa respectively.
การปรับปรุงสมบัติทางกลของพอลิแลกติกแอซิดด้วยเส้นใยปาล์มน้ำมัน
This research work was to study the improvement of toughness of polylactic acid (PLA) and the cost reduction of raw material with addition of untreated and treated oil palm fiber (OPF). The detail of this work was divided into two parts. The first was to find the suitable condition for surface treatment of OPF with sodium hydroxide (NaOH). The second part was to study the effect of untreated and treated OPF contents on the mechanical properties of PLA. For surface treatment of OPF NaOH concentrations and immersion times were varied from 0 to 15 wt% and 0 to 30 min respectively. Aspect ratio (L/D) and surface of untreated and treated OPF were investigated by using optical microscope and scanning electron microscope (SEM) respectively. The result suggested that the most suitable condition for surface treatment of OPF was NaOH concentration of 10 wt% at immersion time of 20 min. Treated OPF was occurred microporous and had more rough as compare to untreated fiber. For the effect of untreated and treated OPF contents on the mechanical properties of PLA it was evaluated by tensile and impact testing. SEM was used for investigation of interfacial adhesion and fiber dispersion. The results showed that tensile modulus and impact strength tend to increase with adding 2.5 wt% OPF content and slightly changed at higher OPF content whereas ultimate tensile strength and elongation at break decreased with increasing fiber content. Surface treatment with NaOH led to enhancement of mechanical properties of composite due to improve interfacial adhesion and fiber dispersion.
การพัฒนาบรรจุภัณฑ์เพื่อสิ่งแวดล้อมจากวัสดุคอมโพสิตเส้นใยผักตบชวา แกลบ และใยมะพร้าว สำหรับรักษาอุณหภูมิ
The research was to develop environmental packaging from composite materials hyacinth fiber rice husk and coconut fiber for temperature preservation to replace the use of foam packaging that cannot be degraded naturally. In the composite materials water hyacinth fiber rice husk and coconut fiber at the ratios 7: 1: 2 1 : 1 : 2 and 1: 1: 1 were extruded by heat using isocyanate glue as a solder and testing the physical and biological properties of composite materials as fiberboard. For testing of temperature preservation of the bio packaging heat transfer test to obtain the bio-packaging for the environment the composite materials of fiber water hyacinth rice husk and coconut fiber at the ratio of 7 : 1 : 2 was the most appropriate type. Since it had a density of 0.7 grams per cubic centimeter strength of 26.76 MPa moisture content of 3.8 percent ages and swelling of 26.63 percent ages. In dry condition at room temperature it could store heat for 2 hours and could retain the cold temperature as shown for the temperatures rising from 4 to 30.7 degree Celsius within 2 hours. This research therefore presents a new alternative method of natural fiber composite materials application for temperature preservation in order to reduce the use of foam containers and increase cost value to natural bio waste materials.