CHAPTER 5
TESTING AND MACHINING OF COMPOSITES
5.1 INTRODUCTION This chapter deals with the various tests conducted methods to evaluate the mechanical characteristics of the fabricated composites. Morphological analysis is also carried out using scanning electron microscope set-up to study the microstructure. It also outlines the drilling of composite specimen.
5.2 MECHANICAL TESTS
The mechanical tests were conducted for the specimens sample S1, sample S2 and sample S3 of categories C1, C2 and C3 as per ASTM standards.
5.2.1 Tensile Test
Tensile strength of a material is found out by tensile test. It is the maximum amount of tensile stress that it can withstand before failure. During the test, a uni-axial load is applied on both the ends of
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The flexural strength of a material can be tested by the tensile test. Flexural strength is defined as a material’s ability to resist deformation under load. The short beam shear tests are performed on the composite samples to evaluate the value of inter-laminar shear strength. It is a 3-point flexural test, which generally promotes failure by inter-laminar shear. The flexural strength is expressed as a modulus of rupture in MPa. The three point static flexural test is the most common flexural test. .The schematic diagram of flexural test specimen is shown is Fig. 5.4. It is performed at room temperature and close to 40% relative humidity. In this test, the specimen to be tested is subjected to a load at its midway between the supports and until it fractures and breaks. This test determines the behavior of the specimen when it is subjected to simple beam loading. Flexural test determines the maximum stress induced in the outer most fiber. The flexural test specimen at failure is shown in the figure 5.5. Sample specimens are shown in Figure …show more content…
The cutting speed, feed rate, and drill tool diameter are considered as the input parameters. A Higher cutting speed produces better surface finish and low thrust force. At high spindle speed, the heat generated at the tool edge softens the polymer matrix, which in turn produces low thrust force and good surface finish. The thrust on the tool and material removal rate are highly depends on feed rate. Low feed rate is always preferred for drilling of GFRP composites. The increase of feed rate increases the thrust force. Also the increase in feed rate increases the surface roughness. Further the decrease in feed rate reduces the material removal rate and hence reasonable feed rate is preferred for drilling of GFRP composites. The tool diameter influences the surface roughness and thrust force in drilling of GFRP composites. It seems that as the drill diameter gets smaller, the drilling space becomes smaller as well and thus the smaller cutting force is generated. Researchers found that small diameter drill produces better results in drilling of GFRP composites. But very small drill bits cannot be used for drilling of GFRP
14 3.1) Appropriate tool for production 14 3.2] Forces that act during ideal orthogonal cutting: 14 3.4] Mechanisms and effects of different types of tool wear and catastrophic failure: 15 [3.5] Life of single point cutting tool over multipoint cutting tool: 16 TASK 4 16 P[4.2]Correct tool and machine settings for increasing the hole diameter to precise size. 16
The test can be performed at various pressures depending on the application in which the connector is going to be used. For example, in undersea application the pressure will be high on the connectors. [26] 7.4.2 Insulation Resistance Testing
https://www.concretedecor.net/decorativeconcretearticles/vol-10-no-7-october-2010/highperformance-mix-design-understanding-gfrc-mixes/ 15/1/2018 The GFRC mix is specially engineered depending on the requirements of the GFRC project and the type of GFRC part required.
⦁ The map of the Marcellus Shale. ⦁ To penetrate more fracture the use horizontal drilling. Doing so they are capable of drilling millions of cubic feet of gas. ⦁ Issues in the environment
I have now taken the Strengths Finder 2.0 assessment for the second time, and I am fascinated with the results. Not only for the differences that exist between the two assessments, but for also my most recent results. I first took the assessment in the Spring 2014 semester, about a year and a half ago, and in that time I have had an immense amount of personal growth. Therefore, I was very curious if my results would reflect the same. Not only did it reflect different strengths, but I believe that the results are more accurate than the prior assessment.
The inner moral compulsion to obey is what drives most social organizations. Sykes (2007) described several structural defects that occurred in the New Jersey State prison. Sykes (2007) argues that power in prison is not based on authority therefore prison officials have to find other means to get prisoners to abide by the rules and regulations. The ability to use force to maintain order on a large scale in the prison is an illusion. According to Sykes (2007), Certain privileges such mailing and visiting, personal possessions, time-off for good behavior etc. are given to the inmate all at once upon his or her arrival to the prison.
Strain and Deviance: an empirical test of General Strain Theory of in a Philippine Public University LITERATURE REVIEW Theoretical Background During the past decades, various criminologists developed different theories in an attempt to explain the causes of crime within the society. In return they were successful, as of today it was adopted or accepted, indeed all of theories explain the root causes of crime. One of these theories is anomie or strain theory which originally argues that the lower class frustration to higher class causes crime (Merton, 1938) in attempt to explain why majority of the people who commits crime are lower class.
Brezina, T. (2018).” General Strain Theory”. Oxford Research Encyclopedia of Criminology Available at: http://criminology.oxfordre.com/view/10.1093/acrefore/9780190264079.001.0001/acrefore-9780190264079-e-249. Timothy Brezina is from Andrew Young School of Policy Studies, Georgia State University. He gained his Ph.D from Emory university.
Question 1. The first step I am going to take as the new safety manager of Dosit to bring them up to compliance with the Hazard Communication Standard would be to conduct an extensive chemical inventory check. The current chemical inventory list of 780 chemicals is over two years old and is outdated by a year. Periodic chemical inventory audits should be done at least once a year(David Fender,2012).
The first test was that of an electrical rules check, this check analyses the schematic design and check for flaws within component connections. The second test conducted was on the PCB design in ARES, this tests was a pre-production check, this test looks at the PCB design and checks that all the components are connected correctly and the PCB is suitable to be manufactured without any flaws. Both tests were performed on a pass/fail
Structural Crack - Shear Crack and Extra Compression Loading Crack Figure 1. Shear Crack Figure 1[1] is an example of shear crack found at Swinburne
We were told that this theory is too broad because it explains everything and yet explains nothing. The question of which came first the chicken, or the egg conception is the same of learning is too simplistic. Do we truly learn from those who are closest to us who else can we learn from? We should ask the all-time question, “Why don’t we commit crime?” not why do we.
I had first formal exposure to civil engineering in course “Architecture 1”. This course provided me the fundamental concepts of civil architectural principles such as designing procedure, architectural component’s layouts, functional spaces as well as environmental impacts. To strengthen my concepts I pursued the courses “Strength of Materials”, “Structural Mechanics” which gave me essential knowledge about the external and internal forces occuring in simple structural elements under action of various types of loading as well as fundamental concepts in structural analysis such as modellisation, classification of structures. I gained valuable exposure to the analysis of simple structures submitted to compound loadings by the application of the principle of superposition for such cases as: unsymmetric bending, combined bending and tension or compression, combined bending and torsion, general compound loading. Futhermore, I was fascinated by the force method and displacement method for analysis of statically and kinetically indeterminate structures.
The structural strain theory was developed by sociologist Robert K. Merton as part of the functionalist perspective. Strain occurs when individuals find it hard to achieve cultural goals through institutionalized means (Merton, 1938). This theory suggests that there are five responses to strain, which include conformity, ritualism, innovation, retreatism and rebellion (Andersen and Taylor, 2009). The responses are developed based on two factors, which are, first, whether the individual accepts or rejects the cultural goals of the society and second, whether the individual accepts or rejects the instituitionalized means of achieving them. To understand this theory, we first have to understand what cultural goals and the institutionalized means of achieving them mean.
This truss is structure of connected elements forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges. The basic types of truss bridges shown in this article have simple designs which could be easily analyzed by nineteenth and early twentieth century engineers. A truss bridge is economical to construct owing to its efficient use of materials.