IndustryEnergy, marine

Business challengesMeet growing sector demand for specialist composite knowledge and FEA skills

Keys to successFemapFemap API

ResultsSignificant reduction in blade modeling time; one week cut to less than one day, more than an 80 percent productiv-ity improvementA better bladeFEMPLY ply-based modeling add-on for Femap marketed commerciallyFast company growthWorldwide contracts

Analysis is vital to ensuring viable, efficient and reliable design, manufacture and operation of composite structures

The windiest country in Europe According to RenewableUK, the trade and professional body for the United Kingdom (U.K.) wind and marine renewables indus-tries, the U.K. is the windiest country in Europe – so much so that this free fuel could meet the power needs of the coun-try several times over. RenewableUK notes that there are over 4,000 wind turbines currently operational in the U.K., with a total capacity of 7.391 gigawatts (gw), enough to power over 7 million homes. It is estimated that by 2016, there will be 8 gw of offshore capacity installed, with a total of 18 gw by 2020. However, there are significant engineering challenges associated with such substantial growth that companies such as PlySim, based in Edinburgh, U.K., are already successfully addressing.

Composite structural engineering specialistPlySim Ltd. (Plysim) is a composite struc-tural engineering consultancy, with heavy focus on finite element analysis (FEA). Its main markets are in the renewables sec-tors (wind, wave and tidal) as well as marine and civil engineering. Malcolm Wadia, director of PlySim, says, “We work

Femap

www.siemens.com/plm/femap

PlySimPlySim meets composite structural engineering challenges; results include a 500+ percent improvement in modeling productivity, plus a better blade and a growing business

with clients worldwide on the analysis of large complex structures in composite materials, having materials tested if neces-sary, developing the whole structural design prior to analysis, and providing cer-tification reports and full-scale test specifi-cations for each design, if required. Ultimately, we provide the 2D ply layup and production drawings.”

Femap particularly impressive PlySim was established to meet the grow-ing demand for specialist composite knowledge and FEA skills sought by device developers who are new to the market or who need specific skills. Malcolm explains the advantages of using Siemens PLM Software’s Femap™ software: “We evalu-ated a number of possible software solu-tions that we could use at PlySim and Femap was particularly impressive. Its tri-angular and quadrilateral meshing is excel-lent. You can specify default settings, mesh the model and then refine it interac-tively in the areas you feel it is needed.

Femap has all the composite analysis and postprocessing tools we need. Global ply postprocessing is a vital productivity aid. Instead of postprocessing by layer, you can postprocess by ply, which makes it quicker and easier for us to see where problems might lie.”

Femap licenses come with extensive and readily understandable documentation, as well as numerous tutorials and advanced instructional files that really help PlySim’s engineers get the most out of the soft-ware. Being originally written for Windows® software, Femap provides a robust and reliable platform for the com-pany’s analyses. PlySim chose Siemens PLM Solution Partner TEAM Engineering as its Femap supplier. Company management notes, “TEAM has a great reputation, was very responsive and has the technical knowledge to be able to sell Femap. They answered all our questions, too.”

Analysis critical to performance, reliability and long service life Wind turbine blades are generally made from glass-fiber reinforced shells, with glass or carbon fiber spar caps that carry the bending load and shear webs to react

“Here is a tool that will do everything you want at a much lower price compared to its nearest functional competitors.”

Malcolm Wadia Director PlySim

“Given that we are engineers writing for engineers and with our experience using the excellent Femap API, we realized that we could actu-ally create a highly func-tional, ply-based modeler add-on for Femap.”

Malcolm Wadia Director PlySim

to the shear loading. A blade is, to an extent, loaded by its own inertia and passes rapidly through low- and high-wind speed areas with a “kick” every time the blade passes the tower and interrupts the streamline airflow around the tower. The blades are made out of composite materi-als because of the high strength-to-weight ratio and high-fatigue performance of such materials. The composite materials are vital to the blade’s structural integrity, as is the comprehensive analysis that is critical to the performance, reliability and long service life of the blades.

Engineers at PlySim create the computer-aided design (CAD) geometry or receive a CAD model from the client. Composite material properties are then applied: dif-ferent elements of the model will have dif-ferent properties. Applying the complex composite layup to a model can be a long and time-consuming process. Some lay-ups may have zero-degree fiber angle; some may have approximately 45-degree fiber angles, with the thickness varying. The engineers then apply loads and boundary conditions and set up the model in the way that is most representative of its actual operation. Usually linear,

“Had we used something else, it would have made delivering and maintaining our capabilities and growing the business that much more expensive and therefore that much slower. That is why we chose Femap and we’d make the same decision again.”

Malcolm Wadia Director PlySim

buckling and natural frequency analyses are used, though non-linear and dynamic analyses can also be used. The analysis file is then exported to the solver, and the results file read and post-processed using Femap. According to Roy Teng, a PlySim engineer, “If we are work-ing on a blade, we’d typically be most interested in the longitudinal strain, com-paring it with the allowable strain and then making our decisions as to where to apply any extra plies, for example.” He points out, “It can be quite complex to review the results, because there may be a different number of layers in each layup and we have to visualize which fiber angle is failing, and in which direction, in order to modify the design appropriately.”

Blade FE model time down from a week to a dayUsing the Femap application programming interface (API) proved to be particularly valuable to PlySim. For one client project, PlySim needed to produce structural mod-els of the blade to a very tight deadline. To do this, engineers customized Femap through the API to automate the creation of the finite element (FE) models of the blade. The models were built using Femap and the results were visualized and reviewed using Femap. Wadia notes, “As a result of using Femap, instead of it taking a week to build a blade FE model, it took less than a day, a more than 80-percent

reduction in modeling time. It took a week to write the program, but from that point on we could create one blade a day. We had four blades to create, which would otherwise have taken 20 days. It only took us 9 days this way, and we now have a very useful tool for when we need to cre-ate blades in future.”

A better bladeA wind energy material supplier wanted to know the effect of different materials on the static and dynamic performance of blades. The supplier had a number of questions: How much more glass would you need to build a 75-meter blade com-pared with using carbon? What is the dif-ference in material costs? Is there an impact on blade performance? What are the benefits of using carbon compared with glass?

Wadia notes, “We were able to show that the costs of glass and carbon were broadly the same, but carbon offers better perfor-mance. It enables you to have a slightly thinner blade with slightly less drag and potentially produces more power. The peak loading is reduced as it is not loaded as much by its own inertia. As a result of our work, our client could show their large customers the benefits of using carbon spar caps: the material is more expensive but much less is used, costs lower and blade performance improved. You get a better blade at the end of it.”

New commercial opportunities – FEMPLYFollowing the withdrawal of another simi-lar product, PlySim saw a clear need for a ply-based modeling add-on for Femap. Ply-based modeling enables engineers to apply the plies to the FE model exactly as they would lay them up in the mold.

Malcolm explains, “Given that we are engi-neers writing for engineers, and with our experience using the excellent Femap API, we realized that we could actually create a highly functional ply-based modeler add-on for Femap. Then, having written and

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Solutions/ServicesFemap www.siemens.com/plm/femap

Customer’s primary businessPlySim provides composite structural engineering con-sulting services.

Customer locationEdinburgh, Scotland United Kingdom

PartnerTEAM Engineering Lanarkshire, Scotland Huntingdon, England

“As a result of using Femap, instead of it taking a week to build a blade FE model, it took less than a day, a more than 80 percent reduction in modeling time.”

Malcolm Wadia Director PlySim

used it successfully, we knew we could commercialize it. We are now selling FEMPLY directly and through distributors and have become a Siemens PLM Software partner. We launched FEMPLY Express in August and are really pleased with the market response.”

Next, PlySim plans to launch FEMPLY Pro, which will feature curved-surface ply drap-ing and postprocessing, and advanced fail-ure theorems such as Puck and LaRC02. With FEMPLY Pro, the shearing and stretch-ing that changes the fiber angles when draping over a curved surface can be fully taken into account. The drape can then be exported in 2D, so that when the material is cut out and draped, all the fibers are in their proper (as modeled) orientation and the plies fit perfectly every time.

“A tool that will do everything you want at a much lower price”Wadia concludes, “Things have changed dramatically over the past few years. I have witnessed a dramatic growth in the

use of FE modeling within the design pro-cess, rather than as a separate analysis stage and the development of design pro-cedures to accommodate. This is because of advances in the field of FEA made possi-ble by products like Femap. Here is a tool that will do everything you want at a much lower price compared to its nearest func-tional competitors. Had we used some-thing else, it would have made delivering and maintaining our capabilities and grow-ing the business that much more expen-sive and therefore that much slower. That is why we chose Femap and we’d make the same decision again.”