จำนวน Repository ( 1852 )
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.
ค่าไอโซเทอมความชื้นของข้าวเปลือกพันธุ์ขาวดอกมะลิ 105
The objectives of this research were the determination of sorption isotherms and the comparison of mathematical models to determine a suitable model in different temperature ranges for Khao Dawk Mali 105. This experiment was made by placing samples in containers which were contained saturated salt solutions to control the humidity in the ranges of 5.32 – 84.34 %RH and the hot air oven was used to provide temperature conditions at 25 and 70 oC. The samples were in containers until the mass of samples was constant so the equilibrium between the samples and the surrounding was reached and then the equilibrium moisture content was determined. The experiment found that for the same relative humidity in the air when the temperature increased the equilibrium moisture content would decrease and for the same temperature in the air when the relative humidity increased the equilibrium moisture content would increase. Furthermore the comparison of models by analysis from R-Squared (R2) and Chi-Square (χ2) in each temperature found that Henderson model was a suitable model at 25 oC and Chung & Pfost was a suitable model at 70 oC.
การออกแบบรูปแบบล้อรันแฟลทที่เหมาะสมสำหรับรถยนต์บรรทุกปกติขนาดเล็กติดเกราะด้วยระเบียบวิธีไฟไนต์เอลิเมนต์
Run flat wheels for small armored regular trucks have been re-developed by transformation from the original metallic material to compound materials polymer group materials as important raw materials then added with aluminum oxide powder to achieve higher strength and wear resistance. The research was performed by using reverse engineering processes including designing and analysis with finite element methodology with the SolidWorks Simulation program and comparing the analyzed results with outcome experiments. Several variables used for the design and analysis were 1) the optimal width of the run flat wheel at the parts both attached to the wheel pan and contacted with the inner rubber surface 2) internal and external radiuses. The internal radius is depending on the size of the wheel pan and the external radius is a variable that determines the height of the Run flat wheel. 3) the shape designed to prevent wearing of the inner tire surface of the run flat wheel and the shape of the run flat reel in the part contacted with the wheel pan. This wheel pan part is such uneven inclined area which is difficult to hold. 4) a design locking kit for tightly fastening the run flat reels to the wheel pan 5) the material used to create the run flat wheel and 6) tire pressure. The run-flat wheels were then designed and constructed in a modular form of 3 parts for ease of the wheel pan assembly. In designing pattern the assembling run flat reels had to be fit into the characteristics of a small armored regular truck wheel pan convenient to assemble with a wheel pan and tightly attached without looseness or deformation when impacted. The run flat reel gripping device has been redesigned to lock all three run flat parts together. It brought up the impact resistance from body weight was at 50 km/hr.
การเปรียบเทียบภาระขาดของรอยเชื่อมผ้าทอทางสถาปัตยกรรมจากการเชื่อมลมร้อนและเหนี่ยวนำ
Architectural fabrics were continuously developed on their unique performance. Architects and Engineers designed them for the application of important buildings around the world despite the symptom that Architectural fabric sizes from manufactures are smaller than the application sizes. Recently although the well-known method used to weld Architectural fabrics to enlarge their size is the high frequency welding there were some application issues. To mitigate those issues the researcher created the hot air welding to replace the high frequency welding in consideration on the failing loads of welded seams which are variable factors of the failing loads to indicate the weld strength and it is crucial for the Architectural fabric application. This research presents the comparison of failing load of weld seams between the hot air welding and high frequency welding by the test of Taguchis Orthogonal arrays L25 method. The test results demonstrated that Architectural fabrics welded by the hot air welding has the highest failing loads of wrap equal to 95.38 kN/m and the highest failing loads of weft at 86.17 kN/m. Conversely Architectural fabrics welded by the high frequency welding has the highest failing loads of wrap equal to 101.37 kN/m and the highest failing loads of weft at 97.78 kN/m. Based on a forementioned results there is no significant difference from both welding methods and thus concluded that the hot air welding could be used to replace the high frequency welding method.
การวิเคราะห์พารามิเตอร์ที่มีผลกระทบต่อความสามารถในการต้านทานของการเจะทะลุของกระสุนบนผิวเกราะอะลูมิเนียมด้วยระเบียบวิธีไฟไนต์เอลิเมนต์
This research analyzes the parameters affecting the penetrating resistance of shells on the armor surface by the finite element method. In this study the results were compared with real bulletproof armor firing tests and finite element simulations. modeling of bulletproof armor using Solid Works program. Creating and simulating armor firing pattern using ANSYS Explicit Dynamic program. damage test is based on National Institute of Justice level 3 standards with material of the ammunition is 7.62 mm tungsten carbide (WC) and speed 847 + 9.1m/s. there are two types of bulletproof armor used in this simulation 1. SKD11 2. Aluminum AL7075. The simulations is into 1 category Simulation of stacked armor plates. The sizes of the armor plates are 6 8 and 10 mm and the angles of firing of bulletproof armor are 0 30 and 45 degrees. result of this simulation armor thickness and firing angle are factors of penetration resistance. when the angle of the projectile is tilted it will cause the projectile to deflect reducing the frictional contact from the impact.