Contact Stress Theory
Chapter -2 Literature review
High stresses are induced when a load is applied to two elastic solids in contact. This can cause serious issues in the optomechanical design if not considered and addressed properly. Contact between two continuous, non-conforming solids is initially a point or line. Under the action of a load the solids deform and a contact area is formed. Hertz contact stress theory allows for the prediction of the resulting contact area, contact pressure, compression of the bodies, and the induced stress in the bodies.
2.1 Analysis of surface and sub-surface cracks due to fatigue D. Finney Charles, R. Gnanamoorthy (2010) investigated rolling contact fatigue (RCF)
…show more content…
Since all fundamentals of rolling contact fatigue are present in a deep groove ball bearing or a spur gear, these applications are used to exemplify the application mechanics.
As we know the mechanics differs between applications it is realised that the rolling contact consists of some common geometric properties. The nominal contacts can be regarded a two dimensional or line contact where Hertz contact conditions exists.
2.3.1 Hertz pressure Hertzian contact stress refers to the localized stresses that develop as two curved surface come in contact and deform slightly under the imposed load. This amount of deformation is dependent of modulus of elasticity of the material in contact. It gives the contact stress as a function of the normal contact force, radii of curvature of both bodies and modulus of elasticity of both bodies .Hertzian contact stress forms the foundation for the equation for load bearing capabilities and fatigue life in bearings , gears and any other bodies where two surfaces are in contact .
Assumption in Hertzian theory :-
• Strains are small and within the elastic limit
• The surfaces as continuous and non-conforming(implying that the area of contact is much smaller than the characteristic dimensions of the contacting
…show more content…
Therefore, the material is case hardened, which gives increased surface hardness combined with residual compressive stresses present at the surface. It should be noted that although the hardness and the residual stresses from heat treatment are results of the same process, the material hardness is only dependent on the local material state whereas the residual stress distribution is dependent on the geometry through the equilibrium of expanded and unaffected material. An increasing resistance against surface fatigue with hardness was documented already by Way in 1935. It was also found that the spalls became smaller for a hardened
Nt1330 Unit 9 Final Report
4034 Words | 17 Pagesmaterial Specific features Galvanized iron Sheet metal Slabs of galvanised iron are pushed into the rollers and made to pass through them Rollers made up of grey iron is mostly used for rolling process. High amount of load acting on the material which is at its recrystallization point tends to deform and then sheet metal is formed. Grey cast iron is used and it is considerably harder as it has some graphite content in its mixture which makes it hard. material Specific features iron Surface
Nt1310 Unit 8 Study Guide
387 Words | 2 PagesThe coordinates of the system is defined by , θ = angle of the chassis from vertical, α = angle of tread assemblies from vertical, Ø = rotation angle of tread sprockets from vertical, mc = mass of chassis, mT = mass of tread, ms = mass of sprocket, Lc = length from centre of sprocket to centre of chassis, LT = length from centre of sprocket to centre of tread assembly. The kinetic energies of the sprocket, chassis and tread assemblies are given respectively , T_S=1/2[m_c x ̇^2+J_S φ ̇^2] (1) T_C=1/2 [〖m_c (x ̇-L_c θ ̇ cosθ)〗^2+m_c (〖L_c θ ̇ sin〖θ)〗〗^2+J_c θ ̇^2 ] (2) T_T=1/2[m_T (〖x ̇-L_T α ̇ cos〖α)〗〗^2+m_T (〖L_T α ̇ sin〖α)〗〗^2+J_T α ̇^2] (3) The gravitational potential energy is given by ,
Shell Shock Research Paper
1341 Words | 6 PagesDo you know what people mean when they refer to the term “The War to End All Wars”? “The War to End All Wars” refers to the First World War, which is known as World War I. World War I was between the Central Powers and the Allies. The War began on July 28, 1914 and ended on November 11, 1918. During the war, the soldiers that were involved began to discover symptoms of a mental illness that came to be known as “shell-shock”. The soldiers’ states of mind were often traumatized by the constant explosions and horrifying sights of the different battles.
Tensile Test Lab Report Essay
798 Words | 4 PagesAf, mm2 %EL %AR PS 12.01 1.99 1016.64 42 42.537 61.902 60.000 23.900 3.170 0 Al 12.05 2.03 3278.13 60 134.01 60.000 72.886 13.769 31.48 43.71 HDPE 12.04 3.00 881.313 18 24.400 60.000 291.72 20.332 386.2 86.34 1. Plot the strain-stress curve of the three specimens using the saved raw data. Discuss
Nt1310 Unit 3 Lab Report
1160 Words | 5 PagesThe four test specimens are all made from cold drawn steel. When steel is cold drawn, the crystal structure changes and creates stress. The stress in the grains can be reduced by the process of annealing. Quenching creates small stresses because carbon does not have time to escape. The annealing process is when
Robert Agnew's General Strain Theory In There Are No Children Here
1375 Words | 6 PagesRobert Agnew created general strain theory (GST). According to Agnew general strain theory is a hypothesis to explain why offenders have committed crime due to pressures or strain on them to counteract negative emotions. Agnew defines strains as any sort of situation that causes stress on the individual. This could be death in the family assault, loss of job, injury, financial hardships, or something else. There are two types of strains he focuses on.
Essay On General Strain Theory
1863 Words | 8 PagesSouth Africa strikes many observers as a country riven by excessive and widespread violence. Interpersonal violence is a daily reality for many, and several studies of crime statistics indicate that poorer people are more likely to be subjected to such violence. Given that the overwhelming majority of people in South Africa are poor, this means that the majority of those subjected to violence are likely to be poor. Then there is community violence, whether in the form of street gangs or the vigilante groups who fight them with similar methods, because many communities feel under-protected by the various state agencies responsible for safety and security in South Africa. These policing agencies are themselves also accused of using excessive force.
Zinc-Nickel Alloy Research Paper
87 Words | 1 PagesIt is more important to give a special kind of attention to the corrosion behavior differences of the coatings, to ensure that the new coating is an acceptable as alternative. For instance, recently many zinc-nickel alloys have been utilized for replacing cadmium layers but due to their difference in corrosion behavior, various issues arise. Zinc-nickel alloys exhibit confined corrosion and cracking, whereas cadmium layers are susceptible to uniform corrosion. Anyhow the dissimilarities in corrosion behavior will play a vital role when providing the necessary corrosion protection
Lego Personal Statement
1451 Words | 6 PagesI 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.
Rockwell Hardness Testing Lab Report Sample
1123 Words | 5 PagesWhile waiting, another specimen Al 2024 at room temperature was used to measure Rockwell hardness. There was 1/16 inch steel ball. Instead of diamond, steel ball was used because Al is softer than steel. Minor load was 10 kg and major load was 100 kg. The test specimen is placed on the anvil.
Role Strain Theory
754 Words | 4 PagesSummary The article Couples' Work/Retirement Transitions, Gender, and Marital Quality explored the marital quality of both husbands and wives in adults from ages 50 to 72 who were currently working in their career jobs, recently retired, or remaining retired. The main purpose of this experiment was to determine “...whether the incidence or the sequence of spouses' retirement affects marital quality” (Moen, Kim, Hofmeister 2001). In this study retirement isn't viewed as a singular event, but rather a process that takes time to adjust to for both the husband and the wife.
Stress In The Workplace
1325 Words | 6 PagesINTRODUCTION Stress is a word derived from Latin word “Stingere” meaning to draw tight. (Mojoyinola, 2008) Stress is your body’s way of responding to any kind of demand or threat. When you feel threatened, your nervous system responds by releasing a flood of stress hormones, and including adrenaline and cortisol, which rouse the body for emergency action. Your heart pounds faster, muscles tighten, blood pressure rises, breath quickens, and your senses become sharper. These physical changes increase your strength and stamina, speed your reaction time, and enhance your focus.
Tension Test Lab Report
1182 Words | 5 PagesIntroduction: The objective for the lab was to determine properties of materials by using a tension test. The properties that were determined was Young’s Modulus, ultimate tensile strength, and yield strength. Three aluminum alloys were tested. The first was the AA 2024 , which is high strength used in aerospace applications.
Heavy Metal Stress
907 Words | 4 Pages1. Introduction Bacteria have evolved several different mechanisms to enable them adapt successfully to their environment. All organisms have intrinsic genetic determinants that are expressed when challenged with different stress factors. Examples of such environmental stressors include antibiotics, chemicals, ionizing radiation, high salinity, extreme hydrostatic pressure, extreme temperatures and heavy metal stress, among others. When faced with single or multiple challenges, a series of transcriptional networks are upregulated to code for determinants that counteract such adverse conditions (1).
Literature Review On Stress
4793 Words | 20 Pages3. Review of literature 3.1 Stress and its types: Stress is an essential mediator of human behaviour. Immediate physiological response to any type of stressor facilitates survival of the species at its maximum. Despite of normal homeostatic regulatory mechanism, the stress responses can become maladaptive. Chronic stress, for example immobilization, exposure to noise, irradiations, psychological stress can leads to a host of adverse health consequences, including cardiovascular diseases, neurodegeneration, obesity, depression and early ageing (McEwen et al, 2004).
More about Contact Stress Theory
Nt1330 Unit 9 Final Report
4034 Words | 17 PagesNt1310 Unit 8 Study Guide
387 Words | 2 PagesShell Shock Research Paper
1341 Words | 6 PagesTensile Test Lab Report Essay
798 Words | 4 PagesNt1310 Unit 3 Lab Report
1160 Words | 5 PagesRobert Agnew's General Strain Theory In There Are No Children Here
1375 Words | 6 PagesEssay On General Strain Theory
1863 Words | 8 PagesZinc-Nickel Alloy Research Paper
87 Words | 1 PagesLego Personal Statement
1451 Words | 6 PagesRockwell Hardness Testing Lab Report Sample
1123 Words | 5 PagesRole Strain Theory
754 Words | 4 PagesStress In The Workplace
1325 Words | 6 PagesTension Test Lab Report
1182 Words | 5 PagesHeavy Metal Stress
907 Words | 4 PagesLiterature Review On Stress
4793 Words | 20 Pages