จำนวน Repository ( 9 )
การการศึกษาพฤติกรรมค่าความจุความร้อนของวัสดุความเสียดทาน
Nowadays one of the automotive engineering is conductivity of brake pads playing a role in friction coefficient which means safety of customer. Thus thermal properties have been improved using composited materials. This project aims to study the heat capacity behavior of 3 different brake pads which are supported by the company Compact International (1994) Ltd. For experimental works temperature based on brake condition was simulated from 05 to 003°C at 5 MPa of pressure. By standard JIS D4413 testing condition of pressure was referred. The heat capacity values of brake pads are calculated under the temperature conditions. As a result of testing brake pad made of copper or high metal powders result in relatively low heat capacity. On the other hand brake pads containing fiber and a large amount of fillers result in an increased heat capacity and stability in various temperature conditions. The heat capacity varied according to the operating temperature. In addition the lubricant contained in the brake pads affects the higher heat capacity and stability at various temperatures.
การศึกษาพฤติกรรมค่าการนำความร้อนแบบไม่เชิงเส้นของวัสดุความเสียดทาน
Nowadays one of the automotive engineering is conductivity of brake pads playing a role in friction coefficient which means safety of customer. Thus thermal properties have been improved using composited materials. This project aims to study the conductivity behavior of 3 different brake pads which are supported by the company Compact International (1994) Ltd. For experimental works temperature based on brake condition was simulated from 200 to 400°C and cooled down from 400 to 200°C at 1 5 and 8 MPa of pressure respectively. By standard JIS D4413 testing condition of pressure was referred. The non-linear of conductivity value are calculated from the temperature under steady state condition. As a result of testing there are several of parameters effecting on the non-linear conductivity value. The brake pad that is a mix of high-fiber affects the fluctuation of thermal conductivity. At the same time lubricant in the brake pad cause the stability of conductivity value in different temperature range at the same pressure. On the other hand the brake pad mixed hi-copper inspires the narrow range of conductivity value in different pressures at the same temperature. Moreover the conductivity value as a mention is inversely proportion with the coefficient of kinetic friction.
การเพิ่มสมบัติทางไทรโบโลยีของผิวอลูมิเนียมด้วยกระบวนการทางเคมีไฟฟ้ากับนาโนซิลิกอกนไดออกไซด์
Aluminum is a lightweight material which are popularly used in various parts of the industry. However there are some limitations on the tribological properties such as abrasive wear and friction when it was compared to other metals. Tribological properties of aluminium was improved with anodizing process and silicon dioxide supplement. the effect of time on surface structure and friction coefficient were studied with with scanning electron microscope and sliding wear tester. It was found that friction coefficient of aluminium was decreased after improvement process was applied.
เครื่องทดสอบพฤติกรรมความเสียดทานของผ้าเบรก
Nowadays the automotive industry in Thailand has been widely growing. Brake pad is one of the automotive products that play a vital role in automotive industry because it is the most critical seeurity part. Consequently testing products for quality are extremely requested. However the precise equipment and function tests which show the real effects are not available enough and cost a lot. Therefore they cannot response to the deman in the automotive industry development. In this study the frictional test jigs for friction measurement JIS K7125 [5] and the clutch facings for automobiles JIS D4311 [6]. A study of the frictional test emphasizes on the static friction (μs) and kinetic friction (μk) in different condition. There are 3 specimens of brake pad supposted by the industry company. These specimens were tested and the results from the pin-ondisk and those from the friction testing were compared. The results revealed the correspondence of the two-sided results but the pin-on-disk’s friction coefficient is more than the friction testing’s friction coefficient by 19.56%. Moreover the coefficient of friction varies according to the temperature Besides the static friction (μs) is likely more than kinetic friction (μk) and tends to differ considerably under high pressure condition.
อิทธิพลของความเร็วรอบที่ส่งผลต่อสมบัติทางกลของการเชื่อมอะลูมิเนียมต่างชนิด ระหว่าง SSM7075 กับ SSM356 ด้วยการเชื่อมเสียดทาน
The objective of this research is to study how rotation speeds affect mechanical properties with friction welding between semi-solid metal 7075 aluminum alloys and semi-solid metal 356 aluminum alloys. The factor of interest is rotation speeds with different conditions at 800 1000 1200 1400 and 1600 rpm respectively. 1.8 millimeter for burn of length 30 seconds for welding time and clockwise rotation are set as a control constant condition for the entire experiment. After friction welding we found that different rotation speeds significantly affected mechanical properties of these alloys. At rotation speed 1400 rpm the maximum tensile strength is 122.24 MPa and the maximum hardness in welded zone is 140.5 HV. The microstructure size is 2.250 µm long and 2.144 µm wide. Its size in welded zone is practically small because of friction force. Moreover this friction force causes the mixture of MgZn2 and Mg2Si in welded zone.