Fatigue failure happens in metals at strenght less than ultimate or yield strenght due to repeated loading. Fatigue failure is due to crack formation and propagation. A fatigue crack will typically initiate at a discontinuity in the material where the cyclic stress is a maximum.
Reasons for discontinuities or crack propagation are:
Utilizing free-body diagram analysis of a very complex structure or machine can be simplified by successively isolating each element and studying and analyzing it by the use of free-body diagrams. Free-body diagram is essentially a means of breaking a complicated problem into manageable segments, analyzing these simple problems, and then, usually, putting the information together again.
Product design engineers deal with lot of uncertainties in product development. Uncertainty always accompanies change. Design factors, material properties, temperature, pressure, load variability, and validity of mathematical models etc. are among concerns to designers.
In product design and development costs, tolerances are perhaps plays most significant role. Tolerances, surface finish, and manufacturing processes are interrelated and influence the production of the end product in many different ways.
Mechanical engineers work with various standards and codes in their day to day work. A standard is a set of specifications for parts, materials, or processes intended to achieve uniformity, efficiency, and a specified quality.
A code is a set of specifications for the analysis, design, manufacture, and construction of something. The purpose of a code is to achieve a specified degree of safety, efficiency, and performance or quality. It is important to observe that safety codes do not imply absolute safety.
Simple comparision between Repairs and Maintenance for a machine as below,
Repairs: repair is the process of bringing the defective machine into efficient working condition. Every machine has to be repaired sometime or another. Some money has to be spent on the maintenance charge can be determined with the help of diminishing balance method.
In this article we will visit what is value engineering and checklist points for value engineering projects. Value engineering in simple is used to determine good design, reduce cost, improve quality, increase reliability and enhance customer satisfaction.
Various areas of a product looked into in value engineering are Material, Standard Parts, Number of parts, Weight, Tooling, Reliability, Maintainability and Process Lead time.
After manufacturing the product few of the important tests are performed in order to make sure product meets intended use. In those product tests Dielectric and Insulation resistance are most common. Insulation resistance test covers the ability of product for property of insulation, whereas Dielectric is measure of isolation.
One should go for brazing when permanent and strong metal to metal joints is required. Mechanically fastened joints such as threaded, staked, riveted, etc. does not have the strength similar to that of brazed joints. Also the braze joints posses the high resistance to shock and vibration, or leak-tightness.
Estimation is an art of finding the cost, which is likely to be incurred on the manufacture of a product before it is actually manufactured. Estimation is one of the important considerations in design for manufacturing and assembly i.e DFMA.