Simplifying Fatigue Analysis

iStock_failed wind turbineOne way to measure the effectiveness of engineering software is the amount of time it takes to reach a sufficiently accurate solution. Simulations by definition are an approximation of reality. Those who solve complex problems— using structural, fatigue analysis, CFD, electronics —  know that we have to pay for more accuracy with additional work and/or longer computing time.

Best in class software enables the user to capture the majority of work done, so it need not be repeated again and again, after all repetition is best done by computers. In this blog we will focus on fatigue simulation, which at first glance can be daunting to new users. There are several different solution methods that can be used with numerous additional correction factors available in most durability programs. There is a “best” combination of methods for most types of problems, which can be guided by experience and expertise. The ability to encapsulate the most appropriate method in a “fatigue workflow” as implemented in ANSYS nCode DesignLife is a major labor saving feature. Continue reading

The Physics of Split-Second Events: Explicit Dynamics

What happens when a bird runs into a plane while the plane is soaring through the air? How do you identify exactly what happened in that split second? And since every action has a reaction, how do you determine if the plane is designed to survive a bird strike? Understanding the physics of split-second events: This is the arena of explicit dynamics analysis.

Now consider split-second impacts in golf. United States Golf Association specifications regulate the speed limit with which a golf ball leaves the face of a driver. Using a standard of approximately 109 mph clubhead speed, approved golf balls leave the face of the driver at about 180 mph on average. If you’re charged with designing balls and clubs, how do you get to the optimal design that meets specs?

Animation courtesy Advanced International Multitech Co., Ltd. Continue reading

To Live Forever – Fatigue Simulations

image of camshaft gear failure

Fatigue simulations can predict product life accurately for any expected loading history. Fatigue is the failure of a part subjected to repeated loading and unloading at stress values lower than the part material’s yield strength. It is the most common form of failure. The cost of failure, in the form of warranty, repair, liability and damaged brand, can be extensive.

But fatigue optimization is not about overdesigning for strength. Product designs that are very conservative can be too expensive or too heavy — and, thus, not competitive. Making informed decisions during the design phase is the best way to prepare products for an ideal, useful life.

Framework for Fatigue Simulations

The ANSYS Workbench environment offers a framework for a complete fatigue simulation. Starting with any CAD model, the ANSYS Mechanical product can predict maximum stress and strain values for any loading. These maximum values can be passed directly to the ANSYS nCode DesignLife program, where they are combined with the expected loading history of a component (or a complete product) during its use to determine the time to failure. With the use of parameters and ANSYS DesignXplorer integrated within ANSYS Workbench, you can optimize product life for cost and weight without risking failure.

We recently held a webinar on this topic. The recording “Optimized Designs for Durability/Fatigue” is now available.

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UPDATE:

ANSYS Seminar – REGISTER
Introduction to Fatigue Theory and Simulation 

Tuesday 17 July 2012
09.00 – 12.45

ANSYS Milton Park, Abingdon, Oxfordshire

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