Technical Tidbits Archive: 2012-2014

Explore some of the unexpected ways that fatigue failures can crop into your designs.

See how fatigue failures are diagnosed in the field, and how to distinguish them from other failure modes.

Discover how to use finite element analysis and other simulation methods to estimate fatigue life.

Learn about the fracture mechanics fatigue method, and how it is used to generate Paris Law constants.

Introduce yourself to the concepts of fracture toughness, and learn what stress intensity is.

Consider the advantages and disadvantages of stress life and strain life fatigue methods compared side by side.

Familiarize yourself with strain life fatigue methods, useful at lower cycles than stress life fatigue methods.

Review the concepts of stress life discussed previously and read some relevant commentary on the accuracy and usefulness of this method.

Learn about Goodman and other diagrams that are used to determine maximum allowable alternating stresses under a given loading condition.

Discover how to use S-N data generated in fully reversed cyclic loading to estimate life under loading conditions with different stress ratios.

Find out how to properly estimate the fatigue life or fatigue strength of your component using statistically relevant data and the appropriate modification factors.

Examine other variables such as anisotropy or edge condition that may affect the service life of your particular application.

Consider how the stress concentration effects of notches, grooves, and corners can reduce the fatigue life of your components.

Determine the effects of component size, geometry, and loading on the fatigue performance of your design.

Discover how to estimate the fatigue strength or fatigue life of your part at temperatures greater than the test temperature.

Read about how the condition of the surface of your part can affect the fatigue life.

See how to come up with a statistically meaningful and relevant fatigue strength or maximum allowable stress for your application.

Examine how the results of fatigue test data are plotted in a usable manner, and how fatigue strength is defined on a case by case basis.

Familiarize yourself with how and for how long the fatigue behavior of a material is characterized.

Learn how the stress ratio describes the severity of a particular cyclical loading cycle, and provides insight into what testing you need to do to ensure reliability.

Introduce yourself to the concept of fatigue failure, and what you can do to prevent the process from causing your design to fail.

Explore how anisotropy and the strain hardening behavior of a material affects how easily you can form it.

Learn about strain hardening in a material, and how it governs the manufacturing and peformance of that material in your designs.

See how easily-measured tensile strength is determined, and how a material's ductility (or lack thereof) influences the appearance of the fracture in a tensile test.

Discover how the elastic modulus helps to determine the performance of your connector design in multiple ways.

Learn the importance of near elastic properties, and the various tests that are used to determine them.

Introduce yourself to the important material properties derived from a stress-strain curve, and how the tensile test is instrumental in obtaining them.

Learn how a tensile test is used to generate a stress-strain curve, which contains many important material properties you need to know about.

Find out how to minimize the insertion force upon mating your connector, without degrading the electrical contact performance.

Learn about Alloy 390, an alloy with strength near that of high strength copper beryllium and conductivity near that of high conductivity copper beryllium.

Review the different considerations for various coating types, and how to choose the optimum material for your design.

Explore the damaging effects of electrical arcing, and what you can do to minimize any potential damage.

Familiarize yourself with the different types of electrical arcing in separable contacts, and where, when and why they occur.

Read about the advantages of silver for contact materials, particularly in higher voltage separable contacts.

Find out where platinum, palladium, and other similar metals are used for electrical contact surfaces, and what to watch out for when you do use them.

Explore the advantages of gold and what makes it an ideal material for electrical contacts, when cost constraints allow it.