MBSE or Model Based Systems Engineering is currently the buzz-word within the systems engineering community; and rightfully so! MBSE system models (e.g. SysML) add the ability to have an “authoritative source of truth” to track the state of a system or product throughout its lifecycle – requirements, structure, behavior, and key parameter values. Compared to the traditional “document” based method of systems engineering – using Word, PowerPoint, or Excel files, this is a long overdue leap in capability for systems engineers.

However, as a systems engineer recently said to me, “Although this is a leap forward in capability, there is nothing ‘sexy’ about tracking requirements. The real excitement comes when we can tie engineering analysis models to the systems models. That is when we can truly make decisions.”

Why is that?

Although MBSE offers tremendous value, SysML models alone are primarily about describing the system – not analyzing it. The real value comes when MBSE systems models are coupled with analysis models, such as those created using HyperWorks. ModelCenter from Phoenix Integration provides the ability to bi-directionally connect system engineering models to any engineering model. The value is that during conceptual design (i.e. proposal writing), your company can incorporate real engineering and cost analysis earlier in the design process – validating requirements and optimizing the system design. This significantly improves the chances of winning projects, reducing costs and timelines, etc. Performance vs. Cost trade-offs can be reviewed to ensure that you can meet your customer’s requirements and find the “knee in the curve“. Ideally, it allows you to upsell to your customer (small cost increase, but significant performance increase), allowing you to differentiate from your competitors.

MaaS – Model as a Service

ModelCenter supports MaaS (Model as a Service), allowing systems engineers to securely access mature workflows (models) across their organization and even into their company’s supply chain while respecting everyone’s Intellectual Property (IP). With MaaS, the workflows and engineering details (IP) stay with the engineering experts and run locally –  only parameters are passed in, and only selected results are passed back to the system engineering level. The domain experts retain control of the engineering models and can provide constraints to ensure that the models are used within proper bounds.

As complex systems rely more and more on their supply chain (both internally within your company and externally via your supply chain), it is becoming more and more important to include your team’s expertise in your solution. Knowing the effects of a change early can greatly improve your chances of winning a proposal and keep your costs under control.

MDAO

So why is all of this important? Adding all of these capabilities together allows a company to perform MDAO (Multi-Disciplinary Analysis and Optimization), which provides systems engineers and domain experts the ability to optimize a design using high fidelity engineering analysis prior to any metal being cut. This shortens the design cycle and allows your company to get the design right the first time…and win more projects! As a system engineer or project leader, imagine not only having your system described via a comprehensive MBSE systems model, but also having ready access to the analysis models that your team is already creating – all integrated together. With MBSE systems models integrated with your analysis models, your ability to make decisions about your product design would be limitless. You would no longer have to be satisfied with your best guesses.

Need some proof?… Check out some of the work presented at the Phoenix Integration’s 2018 User’s Conference. Here you will find many presentations from organizations that are already using and achieving success with this methodology. These presentations show the real potential of MBSE when systems models are integrated with analytical models for complex system design.

Another great source of information is the Stevens Institute Systems Engineering Research Center (SERC), where they have worked with both the U.S. Navy Air Systems Command (NAVAIR) and the U.S. Army Armament Research, Development, and Engineering Center  (ARDEC) on Transforming Systems Engineering through Model-Centric Engineering.

The Coda – How does it work?

ModelCenter sits at the hub of the MBSE integration solution and offers a graphical interface and workflow engine that allows users to automate and integrate any engineering tool — connecting domain expert engineering and financial models with systems models (MBSE). ModelCenter MBSEPAK provides the bridge between the systems engineering models and the analytical models.

Phoenix Integration is a proud member of the Altair Partner Alliance, and ModelCenter and HyperWorks work together to provide you with the best value in engineering analysis and design.

This guest post on the Altair Blog is written by Scott Ragon, Director of Technical Business Development at Phoenix Integration, developer of model-based engineering software, ModelCenter®. Phoenix Integration is a member of the Altair Partner Alliance.

Admitting that the headline is somewhat provocative, this is the exact situation in strength assessment of components made of metals. One might think that the task of evaluating the mechanical strength of a component should be a mundane thing since machine parts made of metals have been manufactured for centuries. In practice, the opposite is true. Giving equally simulated FEA results to different engineers leads to a whole bunch of different assessment results even for a simple assessment of static strength. For fatigue strength, the situation is even worse, since by nature, fatigue strength properties scatter strongly.

Figure 1: Results of a fatigue assessment applying different concepts and software tools

In Figure 1, results of a case study are shown where different companies where asked to predict the fatigue strength of an equal steel component with their particular approaches and software tools based on given FEA results. The assessment results differ in order of magnitude between each other as well as from the experimental result. For other problems in the same survey, the ranking of the applied methods was completely different, while the range of results obtained by the different approaches remained nearly the same. The important point here is that apart from the intrinsic problem of scattering of the real strength properties, additional fuzziness is added by undefined evaluation processes. Subsequently, comparability e.g. between assessment results obtained by an OEM and a supplier might not be given. This shows that there is not a lack of techniques and software but a lack of an agreed procedure or an applicable standard.

Such a standard should unambiguously define how to proceed in order to get a proper assessment of the static and fatigue strength alike. With respect to that, it should leave as few as possible decisions to the engineer conducting the assessment. It should be applicable in the scope of a daily business routine taking into account limited resources of time, software licenses as well as the experience of the user. Additionally, the problem of the scattering of the fatigue properties themselves should be tackled by offering material strength properties of specific grades to a certain survival probability as well as giving safety factors for particular consequences of failure.

With the so-called FKM guideline[1] indeed such a standard is available. It is a German guideline with full title “Analytical Strength Assessment of Components Made of Steel, Cast Iron and Aluminum Materials in Mechanical Engineering”. It is a comprehensive guideline with approx. 230 pages describing the static and fatigue strength assessments based on local stresses, thus it is applicable for results obtained by FEA. Unlike standards like the ASME, the FKM is not product- or industry-specific, rather it is applicable in a most general manner. The concepts outlined in the guideline have its origins back in the 60s of the last century, whereas its first edition was published at the beginning of the 90s. Now it is in its 6^th revised edition from 2012. As of today, the FKM guideline is the de-facto standard at least in German-speaking countries, when it comes to strength assessment of machine parts. However, due to its mere volume and the complexities of the concepts applied, its usage for strength assessment of FEA results would be a rather tedious job. An automated solution is indispensable.

Figure 2: Example of a cast iron machine part in S-Life-FKM – Cyclic utilization ratios as contour plot

S-Life-FKM by PART Engineering is a software that enables an easy and automatic assessment of FEA results according to the FKM guideline. The software is used as a postprocessor interacting with the particular FEA software of the user. Unlike multipurpose fatigue solvers, S-Life-FKM is streamlined to exclusively reflect the FKM guideline. Therefore, with S-Life, at the push of a button the computed stresses will be processed in such a manner that an assessment of the static and fatigue strength according to the FKM guideline for non-welded parts is carried out. As result of the assessment, the static and cyclic utilization ratios will be displayed as a contour plot (Figure 2). A comprehensive numerical report of the most relevant computation results can be requested nodewise for documentation and checking purposes (Figure 3).

Figure 3:  Example extract from critical node report in S-Life-FKM

The S-Life user can get the following benefits from its usage:

• Easy-to-use, even for the occasional non-expert user
• Huge time-savings compared to a manual assessment
• Reliable results according to a proven assessment scheme
• Unambiguous Go-NoGo – decisions
• Well documented results for quality assurance and customer communication purposes

Approx. 1500 grades (steel, cast iron, aluminum, cast aluminum) from the FKM material tables are completely provided by S-Life. Own materials can be added into the database. The FKM guideline can be considered as “Theory Manual” for S-Life. The guideline is available in English language as well. S-Life-FKM can be accessed through the Altair Partner Alliance.

[1] FKM = „ForschungsKuratorium Maschinenbau e.V. (FKM)“, engl. „Research Foundation Mechanical Engineering“

This guest contribution on Innovation Intelligence is written by Dr. Wolfgang Korte, Managing Director at PART Engineering, developers of CONVERSE and S-Life-FKM. PART Engineering is a member of the Altair Partner Alliance.