- Expanded our team! We welcomed 35-year Goodyear veteran Tom Ebbott to our team as Vice President, and at one point we had 3 interns working with us this year. It wasn’t all hard work – we enjoyed our first company canoe trip / picnic in July.
- Solved much bigger problems. We set a record this summer for the largest rubber fatigue analysis ever. Ford Motor Company gave us multi-channel recorded road load histories from the full schedule of 144 distinct test track events that they use to qualify a motor mount for durability. We used Endurica EIE to map the load space and generate 3.2 Terabytes of stress-strain history for fatigue analysis. The new Katana multi-threading architecture of our Endurica CL fatigue solver enabled us to process 152k elements through all 15,693,824 timesteps of the schedule. Check out our presentation at RubberCon 23 in Edinborough UK.
- Made analysis of block cycles easier. The Endurica CL and DT solvers’ Katana architecture now enables multiple blocks of load history to be specified in a single analysis.
- Added a Haigh diagram visualization to the Endurica Viewer. Use it to quickly understand your material’s dependence of fatigue life on mean strain and strain amplitude.
- Implemented a channel reduction algorithm to Endurica EIE. It will analyze your multi-channel loading history to check for opportunities to reduce the dimensionality of your analysis through a change of coordinate basis. Often, a 6-channel signal can be reduced to 3, 4 or 5 channels, greatly reducing computational requirements for building the map for EIE’s interpolation process.
- Expanded our licensing model to offer local, regional and global options. If your organization uses Endurica at multiple sites around the world, ask us about the advantage of regional or global licenses. These licenses allow any number of users to share a pool of solver threads for maximum flexibility and compute power.
- Added an experimental characterization for ozone cracking. Ozone is a trace gas that strongly reacts with some rubbers to produce surface cracking. It limits useful product life, even for loads below the fatigue threshold. Our testing method gives you the parameters you need to set up the ozone attack model in your Endurica CL / DT analyses. Perfect for analysis of tire sidewall endurance.
- Were honored when our founder and president, Will Mars, received the Herzlich Medal – the highest award in the tire industry – at the International Tire Exhibition and Conference. This honor is bestowed every other year to recognize an individual whose career and accomplishments have changed the tire industry for the better and left a lasting impact on tire design, development and manufacturing.
- Strengthened our documentation. New and experienced users alike will find it easier than ever to find the theory, procedures and examples that will yield rapid success in applying our software workflows. Check out the new sections on Mullins Effect, Ageing, Safety Factor, and Block Cycle analysis.
- Celebrated our client’s success. Technetics Group (Pierrelatte, France Maestral® R&D Sealing Laboratory) and Delkor Rail (New South Wales, Australia) shared their Winning on Durability success in case studies.
Once a year, we ask our users to weigh in on what we can do to further improve your experiences with the Endurica fatigue solvers. The feedback helps us aim our development at bringing you winning capabilities. It is also a marker we can use to gauge progress.
Here are the survey results from 2020:
How did we do this year? Check it out:
Support for additional channels in Endurica’s Efficient Interpolation Engine (EIE). EIE makes it possible to compute strain histories and fatigue life from lengthy road load signals. To date, EIE has supported up to 3 independent load channels. But we’ve had several of our best users tell us they need 6 channels. The expanded capability was a big focus for development this year, and now it is complete and nearly ready for launch. Stay tuned for more details to come out in early 2022.
Safety Factor. The Safety Factor calculation is a feature of Endurica’s new Katana CL that launched this year. It avoids the need for full characterization of the crack growth rate law but gives you the benefits of critical plane analysis. Given only the intrinsic strength (fatigue threshold) and precursor size, it calculates the margin by which the most critical loads remain below your material’s fatigue limit. It tells you whether you may expect indefinite life (or not). Use it with the Intrinsic Strength Analyser experiment. Perfect for analysis projects where you need to demonstrate capacity for long life with limited timeline or budget.
UHYPER. Abaqus users can now define their own hyperelastic law in Endurica. The Endurica UHYPER interface matches the UHYPER Abaqus interface so that you can use the same subroutine with both codes.
Linux Support. Did you know that the Endurica solvers are available on both Windows and Linux? Our Linux users can now run the entire Endurica suite of software (CL, DT, and EIE) on their systems.
Execution Speed. The recently launched Katana solver (for CL and DT licenses) offers unprecedented speed. Our benchmarks show that on a single thread, users will cut run times by more than ½. And the Katana solver also offers multithreading. Our benchmarks showed excellent scaling behavior up to >40 parallel threads. These capabilities means that users will be able to run much larger jobs, and to complete their existing jobs with much shorter run times.
Improved hfi syntax / error checking. Another feature of the Katana solver is its adoption of the json format for the input file. The switch to the widely adopted json standard means that our solutions are now much easier to script via python or matlab and that there are file editors which automatically do the syntax / error checking.
Cosimulation Interface for Ansys. The cosimulation capability of Endurica DT updates the finite element solution so that material property evolution can be simulated. It has previously only been available to Abaqus users, but has now been developed for Ansys. It is currently being beta tested. We expect to launch this addition in Q1 2022. This means that Ansys users will very soon be able to make full use of Endurica DT’s Cyclic Softening modules and Ageing Workflow.
Materials database expansion. The next Endurica release will have an addition to the materials database: a series of six HNBRs. We are also preparing to release the database in several common unit systems, rather than the prior single unit system.
With 2021 behind us now, its time to look forward to 2022 (and beyond!). Look for the client survey and let us know how to best serve your upcoming needs.
Rubber can be formulated in a very wide range of properties. For materials developers, this cuts two ways. On one hand, it means that there are almost always excellent options for a given application. On the other, it means that those options are usually hidden among lots of bad options. This is job security for rubber compounders, but it unfortunately also underlies the fact that there are so many instances of sub-optimal materials selection decisions when it comes to rubber. One study found that more than 40% of rubber product failures could have been avoided with better materials selection.
One cause of this statistic is poor visibility into how material properties map into application performance. Too often, the material options are judged based on an over-simplified lab test, or an incomplete specification of application conditions. We made the CompanionTM app to address this gap. Companion makes it easier to find the rubber properties that ensure durability in your application. Companion can compare materials for strain-, stress- and energy control. It can compare applications with different modes of deformation (tension, compression, shear). It can account for fully relaxing and nonrelaxing loading. It can account for temperature effects.
Another cause of too-high rates of poor materials selection is that sometimes different parts of an organization use incompatible approaches to specify, characterize and analyze the material and the application. Gaps between the materials, product and testing silos sometimes create unnecessary confusion, conflict and wasted effort, leading to poor durability. Companion was built with the aim of getting materials engineers and product engineers using a common, validated framework. The material properties and analysis principles in the Companion App are the same as those used in our product simulation software, but the user experience in the app is centered around the materials selection decision. No special knowledge of fatigue theory or simulation technology is needed to start using the app.
You can use the basic version of Companion for free. Go to companion.endurica.com to set up your account and try it out. The free version lets you define one material and one loading condition. A subscription-based professional version is also available for about $1 USD / day. The subscription version lets you compare 2 materials and 2 load cases side-by-side, it lets you save your material definitions to a local database for future use, and it includes several outputs that give deeper insight into the fatigue behavior of your materials. The workflow is simple: 1) define your material(s), 2) define your load case(s), 3) run the calculation, and 4) review the results and compare performance of the materials for the given load cases.
Give it a try and let us know what you think.
Road load signals are notoriously difficult to work with. The signals feature so many different time increments that it becomes too much to directly model efficiently in FEA. It is difficult to tell which portions of the loading do the most damage. Experimental fatigue testing would be too time-consuming and costly to run on the full complex road load signal. For these reasons simplifying road loads into block cycle schedules has become the gold standard for working with road load signals. Experimental testing and FEA modeling are more manageable when using a block cycle schedule instead of the full road load signal. Traditional methods of converting a road load signal to block cycle schedule can often fall short. Endurica recently added a built-in method in the Endurica CL software that uses the power of critical plane analysis and rain-flow counting to automate block cycle creation.
Let us dive into the process of block cycle creation using an example of a bushing and a road load history. The road loading history shown below contains results for loadings in 3 axes over a time history.
The first step in creating the block cycle schedule is solving for the strain history over the entire road load history. Fortunately, Endurica EIE comes to the rescue in solving for the long strain history. The road load time history does not need to be modeled directly in FEA. Instead, a map is run in FEA to solve for strain history within the bounds of the road loading. Endurica EIE quickly interpolates the strains from this map to create the full loading strain history. In the animation below the map points solved for in FEA are shown as black dots and the bushing traces out the path of the map.
After the full road load strain history has been solved for in EIE the fatigue life for the road load signal is ready to be analyzed in CL. The fatigue analysis of the entire road load signal gives valuable insight into finding the critical location, developing the block cycle, and allowing the fatigue life of the block schedule to be validated against the fatigue life of the road load. The critical location of the bushing is shown in the image below:
At the bushing critical location, all damaging events on the critical plane are taken into account when creating the block cycle schedule. The events are grouped into different bins categorized by two parameters: the peak CED and R ratio. The analyst remains in control by selecting the number of bins to group into. Each of the bins contains events with similar peak CED and R ratio that falls within the bounds of the bin. Within each bin, a representative cycle is identified that when repeated in the block schedule will contribute at least as much damage as all the various events in the bin. This selection process produces a conservative result that ensures that the block cycle will be at least as damaging as the road load.
The bin results from the original history show the number of times each bin is repeated and the total damage from each bin. At this point, the bins that contribute insignificant damage can be safely eliminated from the block cycle schedule to save testing time and complexity without changing the results.
The simplified block schedule is then modeled to check the fatigue life vs the full road load signal. The results show that the critical location and fatigue life has been accurately maintained in the block schedule.
This automated block cycle creation procedure succeeded in producing a block cycle with the same critical location and very similar fatigue life. The block cycle selection was able to re-create the full road load signal using only three different loading blocks.
Endurica CL automated block cycle creation lets you take the guesswork out of block cycle creation and harness the proven power of Endurica fatigue analysis technology to get durability right.
2020 is burned in all our minds as a chaotic and tough year. Just like the rest of the world, Endurica staff experienced times of isolation and loss due to the pandemic. On a positive note, we invested heavily in making our tools and workflows better than ever so that we’re ready to come back strong in 2021. Here is a list of our top new developments in 2020:
Endurica Software Enhancements
- Endurica DT’s new Ageing Feature now enables you to simulate how ageing affects your rubber product. Your compound’s stiffness, strength, and fatigue properties can all evolve with time.
- Our new Linux distribution takes our solutions beyond the Windows world.
- We’ve added an encryption feature to safeguard your trade secrets.
- Viewer Improvements make it easier than ever to visualize your fatigue simulation results.
- EIE Enhancements give you blazing-fast compute speed for full road-load signals.
- We’ve also planned an aggressive development agenda for 2021. Stay tuned for a new Endurica-based smartphone app for materials engineers, for a new feature that computes fatigue threshold safety margins, for a new block cycle schedule extraction algorithm, and more!
- The new Fatigue Ninja Friday webinar series provides step-by-step application training for key the workflows that you need to get durability right. All of the recorded episodes are now available in the online Endurica academy.
- The new Winning on Durability webinar series provides high-level overviews of both technical and business topics so you can connect Endurica tools to your strategic imperatives. All of these recorded webinars are available gratis on our website.
- We’ve recast our in-person training events as LIVE, ONLINE workshops accessible safely around the world.
- Coesfeld Tear and Fatigue Analyser – we hosted Coesfeld President Christian Kipscholl for one of the Winning On Durability episodes (#7). We walked through a demo of the T&FA’s fully automated, high-reliability testing workflow.
- Intrinsic Strength Analyser – we hosted another Winning On Durability episode (#3) focused on understanding how a rapid cutting experiment tells us about long term fatigue behavior. We also completed a successful validation this year comparing direct measurement of the fatigue threshold with a measurement from the cutting method.
Fatigue Property Mapping Testing Service
- We added the Reliability Module to our Fatigue Property Mapping testing service. Use it to quantify crack precursor size statistics when you need to estimate probability of failure.
- We also reorganized the Thermal Module and the Ageing Module into Basic and Advanced levels, to offer a lower price-point when a basic option will suffice.
Want to leverage any of these new capabilities in your next durability project? Give us a call and let’s talk!
We have just launched a few updates to our Fatigue Property Mapping service offerings. The changes were:
- Addition of the all new Reliability Module for those needing to compute probability of failure in addition to fatigue life. The module gives you Weibull parameters to describe the statistical distribution of crack precursor sizes in your material.
- Addition of a pressure-volume test as an optional add-on to the hyperelastic module. Use this add-on when your rubber is loaded under high confinement to the point where its compressibility must be treated more accurately. If the hydrostatic pressure is more than 5% of the bulk modulus, then this option makes sense.
- Split of the original Thermal Module in two components: a Basic Thermal Module and an Advanced Thermal Add-on Module. The Basic Thermal Module provides a dynamic strain sweep to quantify dissipation (for use in computing temperature distribution via FEA) and also provides the temperature sensitivity coefficient on the crack growth rate law. The advanced module provides thermal transport properties (conductivity, specific heat), thermal expansion coefficient (for computing thermal pre-stresses), and additional data points for the dissipation and crack growth rate laws.
- Split of the original Extended Life (Ageing) Module into two parts: a Basic Ageing Module and a Master Curve Module. The basic module includes characterization of unaged and aged samples for stiffness, critical fracture energy, and intrinsic strength. The oven exposure time and temperature for the aged sample is specified by the client, or can be set by Endurica based upon a client-specified life target. The Full Master Curve Module gives both the Arrhenius law activation energy and a master curve showing how stiffness, critical fracture energy and intrinsic strength depend on exposure time and temperature.
Most prices have remained the same, except for the Thermal and Ageing modules. The Thermal and Ageing modules have now been significantly streamlined, so that we now offer service at a lower price.
The new price list and specifications can be found here.