Resources
VEXTEC’s Learning Center provides free access to technical white papers on VLM® technology and self guided tutorials on VPS-MICRO®.
Below are white papers available for free download on details of our methods and validation studies of VLM technology. If you have any questions or would like more information on any of the papers listed below, please contact us.
VPS-MICRO® Tutorials
VEXTEC has created a set of self-guided VPS-MICRO tutorials to familiarize engineering professionals with the capabilities our software brings to the world of component design and reliability. Click below to check out the tutorials available for download today.
VEXTEC White
Papers
Papers
Details of an Example Application of VPS-MICRO®
Validation of VPS-MICRO with Aluminum
Validation of VPS-MICRO with Titanium
Validation of VPS-MICRO for Creep Fatigue of Nickel Based Superalloy
3-D Microstructural Modeling and Simulation of Microstress for Nickel Superalloys
VEXTEC Newsletters
Periodically, VEXTEC publishes newsletters that cover our programmatic activities, events and various industry related topics. We have included a form to join our mailing list for future newsletters and two of our most recent publications in the table below.
Join Our Mailing List
Sign-up using the form below to receive VEXTEC’s latest news and events:
| Date | VEXTEC’s Most Recent Newsletters |
|---|---|
| November 2021 | A New Way Forward with Additive Manufacturing (AM) |
| September 2020 | The Predictive Post: VEXTEC and America Makes TRX Live Webinar Series |
Glossary
As a part of VEXTEC’s Learning Center, we have provide a glossary of common terms used in our white papers and other publications. This section is aimed at those who are unfamiliar with them, therefore we are giving basic explanations without a lot of formulas.
Most commonly used metals are isotropic, which means the material properties are the same in all directions. They are composed of many individual grains, which are non-isotropic. As long as these grains are randomly oriented, the metal will be isotropic.
A grain boundary is the region between grains.
Some damage mechanisms target the grain boundaries. To make longer lasting components, the molten metal is sometimes cooled very slowly so that only one large crystal is formed. This eliminates the grain boundaries altogether. This is expensive, so it is only done on high value components. One common application of single crystal components is turbine blades in gas turbine engines, which are exposed to high stresses and high temperatures.
Fatigue is the damage mechanism that is responsible for most engineering failures. It is caused by loading that is applied and removed. Each application and removal is called a “Cycle”. If the load is sufficiently high and enough cycles are applied, a crack will initiate. Once the crack initiates, it will propagate a small amount for each cycle until it fractures.
Mean stress is the average stress during the application of a cycle. Let’s say we have a component that is cycled between a min stress of 20 KSI and a max stress of 120 KSI. The mean stress is 70 KSI ( [20 ] /2 ). The alternating stress is how much the stress varies (plus and minus) from the mean stress during the application of a cycle. It is equal to half the stress range ( [120 – 20] / 2 ) or 50 KSI in this case.
In fatigue we often talk about R Ratio, which is the ratio of the min stress to the max stress. If we have a component that is cycled between 0 and 100 KSI, the R ratio is ( 0 / 100 ) or 0. This is often referred to as “Zero to max” loading. If we cycle between stresses of -50 and 50, the R ratio is ( -50 / 50 ) or -1. This is often referred to as “Fully reversed” loading.
Fracture Mechanics is the study of crack propagation. Once a crack has initiated, we want to know how fast it will grow.
The stress intensity factor (designated as “K” in formulas) defines the stress field in the region around the crack tip. It is a crucial parameter in fracture mechanics. With it we can determine how fast a crack will grow and how large the crack will be when it suddenly fractures. You may remember spending a lot of time trying figure out what “X” was in algebra class. Fracture mechanics guys are always trying to determine K.
Fracture Toughness is the stress intensity factor at which a crack essentialy causes instant failure. This is a material property which varies with temperature.
The Paris Law relates the crack growth per cycle (designated “da/dn”) to the stress intensity factor range.
If the stress intensity factor range is small enough, the crack will not grow at all. This is the threshold stress intensity factor range.