ASSIGNMENT

 

 

 

 

 

 

 

  

Assignment

Assignment

Question 5

This item examines the likely answers of lubricant formulations to an increase of temperatures in motors in the next decade.

THE PRIMARY FUNCTION of liquid lubricants is to control friction, wear, and surface impairment over the proposed life of a system that comprises appliance elements, for example gears and bearings. Wear and surface impairment happen under boundary or partial boundary lubrication conditions, but not under full hydrodynamic conditions. Secondary purposes are to avert corrosion and to scavenge heat, dirt, and wear debris. Lubricants can furthermore move either force or power, as happens in hydraulic systems.

The alternative of a befitting lubricant counts on system desires and cost, as well as on wellbeing, security, and ecological considerations. For a granted system, minimizing the number of lubricants utilized usually simplifies upkeep and decreases the possibilities of applying the incorrect lubricant. Inventory storage and management are furthermore reduced. Machinery manufacturers assist characterise system desires by suggesting viscosity degrees and the lubricant value that is apt for use with their gear in diverse applications. In some situations, rather comprehensive specifications ruling the oils to be utilised may be provided. With new gear, the recommendations of manufacturers should be pursued to double-check warranty protection. After the warranty time span, the number of distinct lubricants can often be simplified (Ref), with the aid of a skilled lubricant supplier. This item recounts kinds of groundwork oils and the properties significant to lubricant functioning; lubricant classifications; wellbeing, security, and ecological considerations; and procedures of lubricant application. Hydrocarbon-based oils, particularly inorganic oils, are emphasized because they are the most broadly used.

 

Question 7

The Archard wear equation is a straightforward form utilised to recount skidding wear and is founded round the idea of asperity contact. The Archard formula was evolved subsequent than the Reye's hypothesis, though both came to the identical physical deductions, that the capacity of the taken debris due to wear is proportional to the work finished by friction forces. Reye's model became very popular in Europe and it is still educated in university techniques of directed mechanics. This idea has, although, been completely disregarded in English and American publications where later works by Holm [2] and Archard are generally cited.

Archards formula is the rudimentary equation for pertaining general wear rates to the usual burden used on an item, the hardness of the suppler constituent and the wear coefficient. The foremost difficulty arrives in working out the wear coefficient, as this can be leveraged by numerous factors. As you rightly surmise, adhesive and abrasive wear will have distinct characteristics to straightforward dynamic wear. Archards formula presents a good recount of the severity of wear, but it needs "detail". If you desire to address adhesive wear, you require taking account of the element dimensions, artificial deformation of the components and the function of brittle fracture. Adhesive wear can be summarized by

Q = (a'*w**5/4 *d**1/2)/ (A**1/4 * K**3/4 *H**1/2).

Where K = fracture toughness of the material,

H = hardness,

W = burden,

d = linear dimension,

A = locality over ...