Manager’s Guide to Productivity Gains with Multiphysics ... · simulation tools tend to be used by specialists to confirm the decisions that design engineers made, but are not necessarily

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Manager’s Guide to Productivity Gains with Multiphysics Simulation

© 2010 COMSOL, Inc.

Part II: Speed Innovation & Reduce Costs

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What’s the difference between simulation-assisted and simulation-led design? How do these two concepts affect a company’s bottom line? Can one

concept foster product innovation? Simulation-assisted design is a more traditional approach to the overall product development process — it implies that simulation is used to verify design decisions once some tangible design idea exists, and is often expressed either in terms of a CAD model or a physical prototype. “Simulation-assisted design is a commonly used add-on to the product design workflow,” said Keith Howard, Managing Director of COMSOL Ltd. “In this case simulation tools tend to be used by specialists to confirm the decisions that design engineers made, but are not necessarily used in real time to make decisions.” On the other hand, simulation-led design is where scientists and engineers use simulation to explore design ideas and concepts before doing anything else.

While the traditional approach has worked in the past, more companies are gravitating toward using simulation to actually drive the design. What is being realized are the advantages of simulation not simply to verify design decisions, but to explore and develop these new, innovative ideas; come up with viable concepts; and explore all of their “what-ifs” in terms of use of materials or manufacturing methods. The reason companies are moving toward the simulation-led approach is simple: to be competitive, it is no longer enough to get a product to market quickly; it is more important to foster product innovation. By developing products that have the features that customers want, companies gain a more competitive edge.

Being Competitive — Product InnovationAccording to Mr. Howard, in the past 10 to 15 years, companies

have focused on reducing the time and cost associated with the development process. So where lead-time reduction may have been a competitive weapon, now most companies have created fast and lean processes. Today, companies who are able to rapidly come up with more innovative products are gaining a more competitive edge, meaning that today there is a stronger emphasis on innovation than there is on lead-time. “The focus is more on innovation because companies have realized for a long time that they have got to improve their processes for cost and time, and now that they are more competitive in that

regard, it’s innovation that really is more of a driving factor,” said Mr. Howard.

To develop an approach that encourages innovation, companies need to foster the appropriate processes. A critical feature of these processes is making sure that the necessary tools are provided that both allow and encourage the users to quickly create and explore new ideas. “That’s where we see COMSOL Multiphysics playing a vital role. In a more traditional process, there isn’t the time and space to allow this exploration. We often refer to COMSOL Multiphysics as a desktop laboratory because users are free to quickly and easily explore new concepts,” said Mr. Howard.

Creating the Desktop LaboratoryIf simulation-led design is to be a reality, it requires tools

that do not require specialized skills, are comprehensive (they support all physics and all possible interactions), and are cost effective such that they support a desktop implementation and are accessible to everyone. In essence, it is creating a desktop laboratory — the idea of putting this technology on the desktop of engineers and scientists where they would have easy access to tools to model an idea quickly, rather than having to spend that time thinking about how to build a prototype. This is what COMSOL Multiphysics has offered since the beginning. “We have focused from the outset on providing a single, integrated solution that can address the widest range of applications,” explained Mr. Howard.

To support the desktop-laboratory idea, the most recent release of the software (Version 4) features a new COMSOL Desktop™ user interface that makes the power of multiphysics simulation available to a wider audience of scientists and engineers. Both expert analysts and non-experts alike will benefit from the organized layout and streamlined model-building process. “With Version 4, we’ve tried as best we can to have an interface that makes it very logical to use,” explained Mr. Howard. “We are trying to put these tools in the hands of generalists, as opposed to what happens too often with these tools, which is putting them solely in the hands of specialists.” In addition, a series of LiveLink™ options integrates the software into the mainstream product design workflow of Autodesk® Inventor®, SolidWorks®, and Pro/ENGINEER®. CAD users can simulate real-world

COMSOL Multiphysics Speeds Product InnovationHow Simulation-Led Design Can Improve Your Bottom LineCATHLEEN LAMBERTSON, CONTRIBUTING EDITOR, TECH BRIEFS MEDIA GROUP

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physical effects of new products. Mr. Howard said, “The highly refined CAD interoperability tools make it possible to both import and export parts and assemblies from most CAD systems. Moreover, it allows the two systems to link to one another; a user can set up parametric studies whereby COMSOL Multiphysics will ask the CAD system to create specified geometry for analysis.”

The Bottom LineHow does product innovation translate to cost savings

and a company’s return on investment? Implementing COMSOL Multiphysics not only reduces costs by allowing users to design better products with a shorter lead-time, it also fosters product innovation, which gives a company that necessary edge over the competition. “I have personal experience working with companies whose very existence was being threatened because their products were no longer seen by the customers as desirable, as having those features they recognized as being attractive by comparison with the competitors,” stated Mr. Howard. “In these cases, the key priority was to focus on product innovation.” It is all rather simple: by creating a computer model, users can easily evaluate whether a new concept is viable without engaging a lot of resources. And since the process is so fast, inexpensive, and safe, it can encourage creativity and innovation. And where would a company be without creativity and innovation?

Simulation in the Real WorldThe following pages include examples of how companies

have saved time and money, and brought new products to market faster by adopting COMSOL Multiphysics and simulation-led design. For example, learn how B&C Speakers used simulation and modeling to develop a novel acoustic lens for sound systems and dramatically shortened the time needed to find the best design.

In the medical industry, Continuum Blue Ltd. was able to find a manufacturing problem using simulation, enabling them to bring a new one-piece polymeric medical implant to clinical trials.

In the auto industry, General Motors used COMSOL to model advanced materials for their green automobiles, and Metelli S.p.A. saved design time and cost of producing auto parts.

NASA is using simulation to save time and resources in developing experimental equipment to extract water trapped below the Moon’s surface. Back on Earth, multiphysics modeling has helped Osram Sylvania develop energy-saving lamps for indoor and outdoor applications. Also read how COMSOL helped Procter & Gamble save time and money in manufacturing and shipping household products.

For more information about COMSOL Multiphysics and how it can help improve your company's bottom line, visit www.comsol.com or call 1-781-273-3322. n

A turbine stator blade, in the high-pressure stage of a gas turbine, is heated by the combustion gases. To prevent the stator from melting, air is passed through a cooling duct in the blade. The resulting temperature gradients introduce significant stresses. Shown is the COMSOL simulation visualizing the temperature distribution throughout the blade, as well as the von Mises stresses in both welds.

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Engineers at Continuum Blue Ltd. (UK) are developing soft tissue

implants made of biodegradable hyper-elastic elastomers that, once they have served their purpose, dissolve naturally within the body to eliminate the need for surgery to remove them. Founded in 2004, Continuum Blue specializes in the research, development and analysis of medical devices and implants. It has worked with many international companies including Medtronic, Abbott Spine (now Zimmer), Synthes, NuVasive, and Scient’X to name a few.

Novel new ligament implants act like a rubber band to hold together and support bones while providing flexibility. However, they require anisotropic material properties.

For instance, in a rotator cuff LARS (Ligament Replacement and Augmentation System), the implant must be flexible enough to give the patient ease of arm movement without restriction, and at the same time provide sufficient stability.

A single elastomeric material cannot meet the requirements of such a LARS.

Our client developed a novel method of injecting two slow-curing polymers into a mold to create a one-piece implant with the desired anisotropic hyper-elastic properties. With a model, we were able to determine how to best manufacture the device in a single production process. A product based on this process is now undergoing clinical trials.

When developing the first implant of this type, we encountered a manufacturing problem but could not identify the cause in the molding process. We then turned to simulation software for more insight, and in the end only COMSOL Multiphysics was up to the task. In particular, its capabilities to handle full 3D dual-polymer injection and control of the injection profile were not available in any of the specialized injection-molding software we evaluated.

The co-injected polymers are mixed prior to entering the mold, which was simulated by including a boundary condition that describes the volume fractions of the two polymer solutions as a function of the injection rate. This description was very easy to define in COMSOL Multiphysics but almost impossible in other software.

We now can investigate many mold variations with less time and expense. A single mold redesign and trial run with the model takes roughly 1.5 days and costs approximately GBP 850. In contrast, to do a physical sample run

where a specialized silicone mold costs approximately GBP 3,000, the estimated total costs are almost GBP 9,000 and the time to get the redesigned silicone mold is between 3 to 4 weeks.

Finding the critical parameters that control polymer location would have taken much longer and cost 20 times more without COMSOL. The software also gives us far better insight into what is happening during the mold filling process, where the client can easily visualize the end product and the mixed regions between the two polymers. The COMSOL model and the resulting visualizations provide clear cost- and time-efficiency benefits when convincing customers of the best mold process to provide a viable polymeric LARS solution. COMSOL’s capabilities will certainly be a key component to our future. n

Mixed Polymers Form Unique One-Piece Medical ImplantWhen engineers ran into manufacturing problems, a COMSOL Multiphysics model uncovered the cause and helped bring a novel polymeric implant based on the process to clinical trials.BY DR. MARK YEOMAN, R&D DIRECTOR, CONTINUUM BLUE LTD.

“�Finding�the�critical�parameters�would�have�taken�much�longer�and�cost�20�times�more�without�COMSOL.”

Continuum Blue cut costs by more than 90% through simulation of the injection molding pro-cess in manufacturing new polymeric medical implants. The image shows a thermal plot of the mold cavity during filling.

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M y role as an R&D process design engineer in Procter &

Gamble’s Fabric and Home Care Division is to design reliable and cost-effective manufacturing processes for detergents and laundry additive products. Because detergents are complex, I need customized models that couple multiple physics and use unconventional constitutive relations. COMSOL enables me to create these models quickly. I can compare models with experimental results and focus on setting up the physics right, rather than writing code and identifying algorithms for fast convergence.

Quick PrototypingIn one study, I examined the stress

history on structured liquid detergents. It is essential not only to control the chemical composition of liquid detergents but also their microstructure, which can be controlled via shear history during manufacturing. Shear forces are essential to incorporating ingredients, but too much stress is detrimental to product microstructure. Over-shearing will destroy the gel structure, leading to the product physically separating over its shelf life and to undesirably low product thickness. We created a hybrid model to quantify the amount of stress during the manufacturing process so we could predict its effect on microstructural breakdown.

Because a product’s structure changes over time, engineers cannot work with standard fluid-flow equations such as Navier-Stokes. Before COMSOL, our engineers

mostly used physical experiments and empirical results. Sometimes they turned to finite-element software to model fluid dynamics and the shear stresses, but were not able to couple these properties to the structural breakdown. COMSOL provides me, as a non-modeling expert, the capability to work with unusual combinations of physics on my own, relatively quickly. The benefits have been significant. For example, to set up a pilot plant to test a possible process and its operating parameters usually takes at least a week and costs several thousand euros. However, with COMSOL models, I can examine a process design within an hour.

Design OptimizationWe also used COMSOL to investigate

how to prevent thermal runaway decomposition of dry laundry additives, which can occur during storage or shipping and result in a product losing its effectiveness. The possibility of thermal runaway limits the maximum amount of product that can be put on a pallet, especially if it is stored in an unventilated warehouse or transferred in regions with very hot climates. With such a range of storage scenarios, it’s not feasible to conduct physical testing for each possible problem. Instead, we created a COMSOL model that allowed us to study heat buildup and fluid dynamics of natural convection in air pockets around the package.

With the University of Naples, we developed a model to predict the risk

of thermal runaway and were able to establish a maximum safe storage temperature. Once we validated the model, we were able to make recommendations on the number of layers of pallets that could be stacked. This produced a multi-million euros logistic cost saving and helped reduce the environmental impact of the logistic chain. Additionally, the results enabled us to make better decisions as to temperatures that must be maintained in the supply chain, and helped P&G preserve product quality for consumers.

COMSOL proved to be the perfect tool for this work. The COMSOL model is robust enough to handle many different simulation conditions, yet can be run on a standard four-processor workstation with 8 GB of memory and provide real-time results in under an hour. The user-friendly COMSOL interface has also been utilized to design a tool for plant safety managers, enabling them to independently run simulations to assess thermal runaway risks in their plants. n

Simulation Helps Produce Better Household ProductsModeling with COMSOL saves Procter & Gamble time and money in manufacturing and shipping products.BY VINCENZO GUIDA, PROCTER & GAMBLE

A thermal fluid simulation of laundry additive storage using COMSOL Multiphysics helped P&G optimize pallet configuration and resulted in a multi-million euros logistic cost savings.

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Modeling is being used extensively to reduce the amount of energy

consumed by lighting. Worldwide, the energy consumption of lighting is approximately 2,800 TWh, 20% of the global supply of electricity. At a conservative 10 cents per kWh, the cost of this energy is $280 billion per year. For the light-sources industry, gross annual income is approximately $25 billion, one order of magnitude smaller than the cost of energy used for lighting. As we pursue reduced energy consumption in all of our light-source technologies, we expect to offer global energy savings that repeatedly offset the full cost of operating our industry.

High-Intensity Discharge LampsResearch and development of

high-intensity discharge (HID) lamps is a key component of this effort. HID lamps are commonly used to supply light in expansive spaces both indoor and outdoor, where they offer advantages in space and energy efficiency. An HID lamp works by driving alternating current between two electrodes to establish an arc discharge through a gas. The gas is enclosed in a hermetically-sealed arc tube made of quartz or ceramic. Most of the light from a running HID lamp is emitted from the arc, which typically reaches temperatures of 5000-6000 K.

Acoustic waves are generated in an HID lamp through systematic modulation of the current that powers the lamp at frequencies that correspond to standing sound waves. Proper application of acoustics1 has been shown to enable a 50% increase in lamp efficiency over current HID technology.2 If such an improvement

could penetrate the US market, a simple estimate offers potential energy savings of 50 TWH per year, equivalent to the total energy that was generated by wind power in the US in 2008.

Modeling Acoustics with COMSOL

One of the key capabilities of acoustics is straightening a bowed arc in an HID lamp. Arc bowing occurs in a horizontally-running lamp, where strong temperature and density gradients exist between the arc and the wall, and buoyancy forces act to move the arc up against the top wall. Using computer modeling,3 we obtain access to detailed information about the structure of the sound waves4 that is needed to bring about arc straightening.

To develop any new product and bring it to the market, engineers confront a whole host of questions along the way. “Many of those questions can be answered through experimentation, but others can only be answered through analysis of governing equations and this requires modeling. The best industrial models enable the development process by addressing those questions that push beyond the practical limits of what can be measured.”

We use COMSOL® primarily for the flexibility that it offers. Because of the exploratory nature of our modeling, we routinely “user-define” the full set of governing equations and parameterize

every coefficient and dimension. This requires considerable mathematical freedom, much more than the “user-defined functions” that most packages normally offer. The general and weak

forms in COMSOL’s PDE mode, together with scripting through the MATLAB® interface, give us the flexibility that we need to grow our modeling into new areas of research. n

RefeRences1 R. Schafer and H. P. Stormberg, Investigations on the fundamental longitudinal acoustic resonance of high pressure discharge lamps, J. Appl. Phys., 53 (5), p. 3476-3480, 1982.2 K. Stockwald, H. Kaestle, and H. Weiss, Significant efficacy enhancement of low-wattage metal-halide HID lamp systems by acoustically induced convection configuration, ICOPS 2008: Proceedings of 35th IEEE International Conference on Plasma Science, 2008.3 J. Olsen and T. D. Dreeben, “Experimental and Simulated Straightening of Metal Halide Arcs Using Power Modulation”, IEEE Transactions, submitted.4 Lord Rayleigh, On the Circulation of Air observed in Kundt’s Tubes, and on some Allied Acoustical Problems, Transactions of the Royal Society of London, 175 (1), 1883.

Multiphysics Modeling in Discharge LightingResearch using COMSOL software leads to innovative energy-saving lamps for indoor and outdoor applications.BY THOMAS D. DREEBEN, OSRAM SYLVANIA

OSRAM SYLVANIA researchers use COMSOL Multiphysics to build the company’s knowledge base, resulting in innovative new products like their HID lamp. Acoustically straightened arc control enables a 50% increase in lamp efficiency over current HID technology. Thomas Dreeben (left) and Jo Olsen.

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A s General Motors focuses on developing sustainable automotive

solutions from the energy and the environmental perspective, reducing weight of the vehicle, and electrification of the propulsion system have emerged as key priorities.1 These solutions are driven by continual exploration of new materials and manufacturing processes, including composites and multi-material solutions for lightweighting, and robust battery materials for electrification.

Simulating Composite Stresses

Thermoset-matrix composites hold great potential as automotive materials because of their lower density compared to metallic alloys, high specific strength, and good energy dissipation. However, processing of thermoset-composite parts and assembly with thermoset adhesives come with challenges. Cure-induced residual stresses can result in springback of thermoset components after they are released from the mold or in shape-distortion effects in assemblies. Simulations of residual-stress development in thermosets not

only allow the systematic probing of underlying mechanisms that may cause shape distortions, but also present an inexpensive alternative to experimental trial and error to arrive at optimal design and process modifications.

Employing COMSOL, we have developed a model that captures the evolution of residual stresses throughout the manufacturing process and determines their effect on the final shape of the composite part. COMSOL allows manipulation and redefinition of existing variables without resorting to user subroutines. For example, the coupling between heat-transfer and diffusion analysis (to account for the exothermic heat of reaction) was readily available as a part of the standard variables offered in COMSOL. The coupling between diffusion and structural mechanics (to account for shrinkage strains), while not readily available, could be established in a systematic fashion because all the variables are transparent to the user for easy modification.

Modeling of Corrosion PhenomenaThe thrust to reduce vehicle mass has

led to the exploration of multi-material solutions in the automotive structure, body, and power train. Magnesium is the lightest structural material, but its use is limited today mainly by its poor corrosion resistance. To quantify the dissolution rate (corrosion rate) of magnesium joined with steel, we created a model using COMSOL. Because the magnesium surface is continually dissolving in the electrolyte, galvanic corrosion becomes a moving boundary problem and was implemented

using the Moving Mesh application mode. This numerical approach helps in understanding the corrosion mechanism, in selecting materials based on galvanic-corrosion severity, and in providing design guidelines.

Understanding Degradation in Battery Materials

Lithium-ion battery chemistry is the obvious choice for automotive energy storage due to its high gravimetric energy capacity and ability to deliver the power density needed for driving the power train. Capacity fade during charge/discharge cycling is partly attributed to mechanical degradation of electrode material. This manifests due to large mechanical stresses that develop in the electrode materials from volume expansion associated with lithium intercalation. Taking advantage of COMSOL’s multiphysics and customization capabilities, we developed a 3D model coupling the lithium concentration with mechanical strain and subsequently used that to estimate quasi-static equilibrium stresses in the particle. We then used the 3D finite element model to carry out simulations to understand the effect of microstructural aspects, such as particle size, phase-change and crystal anisotropy on mechanical degradation. Eventually, the study aims to offer clues to mitigate stresses and improve battery durability. n

RefeRences1 Taub, A.I., Krajewski, P.E., Luo, A.A., and Owens, J.N., “Yesterday, today and tomorrow: The evolution of technology for materials processing over the last 50 years: The automotive example,” Journal of Metals, 59 (2), 48 (2007)

Modeling Improves Advanced Materials for AutomobilesGM utilizes COMSOL simulations for understanding and improving material and process performance.BY BHASKAR PATHAM, KIRAN B. DESHPANDE, AND SAMPATH K. VANIMISETTI GENERAL MOTORS GLOBAL RESEARCH AND DEVELOPMENT, INDIA SCIENCE LAB

GM uses COMSOL Multiphysics in develop-ing sustainable automotive solutions. This image shows the results from a simulation of the intercalation of lithium ions into a nodular battery electrode particle visualizing the nor-malized lithium concentration (a) and the as-sociated normalized strain energy (b).

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Metelli S.p.A. (Cologne, Italy) designs and manufactures

brake and engine parts, transmission components, and water pumps for OEMs as well as for the aftermarket. A few years ago, our R&D team ran into a situation where the software we had been using was inadequate. We found that COMSOL Multiphysics could handle the job and have relied on it ever since.

We first turned to COMSOL to study the magnetic field in an inverse electromagnetic clutch. We needed a 3D FEM tool both to check the simplifications introduced in our 2D model and to manage complex 3D geometries. We chose COMSOL with the AC/DC Module due to its flexibility and we also found a good agreement between the model and experiment, which meant that no changes were required to start manufacture of the clutch pre-production samples.

Next, we tapped COMSOL to analyze fluid flow in a vacuum-actuated water pump and to gauge the maximum actuation time. We wanted to design a unit that met specifications while building the minimum number of prototypes, each of which can cost 10,000 euros and take two to three months to make. In contrast, model simulations could give us answers to our design questions in just a week or two.

We have more than 600 types of water pumps. When designing a new one to a customer’s requirements, we often want to use existing impellers. With COMSOL, we can safely and quickly compare the performance of a new impeller versus an existing one.

In our latest project, we are investigating contact stresses in a Rzeppa Constant-Velocity (CV) joint, which uses steel spheres instead of gears with teeth to transmit torque at variable shaft angles. Although CV joints have been around for a long time, they are still very difficult to manufacture and simulate. The components undergo varying levels of stress and require different types of materials. With a COMSOL model, we can check that the selected materials can withstand the stresses and estimate their capability to resist them at the maximum loads applicable while maintaining the correct safety factor.

An Expanding Universe of Applications

We like the fact that COMSOL is so flexible and customizable. From our

initial examination of electromagnetic effects, we have expanded our use of COMSOL to study fluid flow, fluid-structure interaction and, lately, structural mechanics. Now we can examine many different aspects of one product without the need to switch among different software environments. And it’s a great plus for us to be able to enter our own equations in contrast to other closed packages where you cannot modify the physics.

We are constantly using COMSOL, and it’s safe to say that we are saving thousands of euros per year in engineering and development costs because of it. It allows us to respond to customer questions more quickly and get products to market faster while completely fulfilling specification requirements. n

Simulation Software Saves Design Time and Costs for Major Auto-Parts ManufacturerCOMSOL answers the need for a flexible, customizable analysis tool. BY FABIO GATELLI AND LUCA ARMELLIN, METELLI S.P.A.

Metelli fully integrated COMSOL in a range of projects to create designs that meet specifica-tions while saving money. This simulation of a Rzeppa joint shows the displacement of the joint when the shaft reaches the maximum angle.

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Recent discoveries by NASA’s Lunar CRater Observing and Sensing

Satellite (LCROSS) are shedding new light on the question of water on the Moon. Preliminary data indicates that the mission successfully uncovered water during the October 2009 impacts into the Cabeus crater near the Moon’s south pole. These findings could have far-reaching implications as space exploration expands beyond low-Earth orbit.

Water and other compounds on the Moon represent potential resources that could sustain future manned lunar outposts. According to Dr. Edwin Ethridge, a Materials Scientist in the Materials & Processes Laboratory at NASA Marshall Space Flight Center (Huntsville, AL), in-situ resources are very important since they do not have to be launched out of Earth’s gravitational well. “It is very expensive to get mass into space,” he said. “For example, it costs around $50,000 per pound to launch anything to the Moon.”

NASA Marshall is investigating the use of microwave technology to extract water from lunar soil. Once the water is extracted, oxygen could be obtained by electrolysis. The basic system comprises a microwave source, waveguides to deliver the energy to the soil, and a cold trap to capture water vapor. First, the microwave energy penetrates and heats the soil. Since ice is relatively transparent to microwave energy, heat is transferred from the soil particles to the

ice condensed onto the surface of the soil. On the Moon, water ice transforms directly to vapor by sublimation. Once in the cold trap, the water vapor will transform back to ice.

Simulating the MoonSince the microwave extraction

process is a complex multiphysics problem, Dr. Ethridge is employing simulation to address the challenges. COMSOL is being used to calculate the microwave penetration into

and heating of simulated lunar soil. “Calculations can be performed on different geometries, for a range of microwave frequencies and different power levels,” said Dr. Ethridge. “Since the temperature varies with time as the soil heats, temperature-dependent soil dielectric properties can be incorporated into the model along with temperature-dependent thermal conductivity of the soil. Whatever the properties of the lunar soil might be, we can simply put them into COMSOL

and do a calculation.”He further explained:

“Development of an early experiment payload for a lunar lander mission requires the specification of the microwave frequency, power, and method of delivery of power. Developing experiments with several different microwave frequencies would require a significant investment of resources, manpower, and time. COMSOL permits the calculation of microwave penetration and heating that could be expected with different experiment scenarios. This can reduce the time, labor, and cost to narrow the hardware requirements for the experiment.” n

Microwaving Moondust with COMSOLCOMSOL is helping NASA save time and resources in developing experimental equipment to extract water trapped below the Moon’s surface.BY CATHLEEN LAMBERTSON, NASA TECH BRIEFS

“COMSOL�permits�the�calculation�of�microwave�penetration�and�heating�that�could�be�expected�with�

different�experiment�scenarios.�This�can�reduce�the�time,�labor,�and�cost�to�narrow�the�hardware

�requirements�for�the�experiment.”

COMSOL is being used to calculate the microwave penetration into, and heating of, simulated lunar soil. This can reduce the time, labor and cost to narrow the hardware requirements for the experiment. The photo shows the demonstration hardware to test the beaming of microwave energy down into lunar soil simulant.

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P rojecting high-quality sound to large audiences

often involves a linear array of speakers. To ensure that every audience member hears every sound with full fidelity, the wavefronts from the individual speakers must be in phase with each other, and the frequency response must be as smooth as possible — ideally flat. The traditional method has been to combine megaphone-variant horns in a coherent array, but even the best horns produce unintended side effects such as diffraction, reflection, and distortion.

In an ideal waveguide, the signal throughout the driver outlet arrives in phase. Over the years, speaker man-ufacturers have employed a variety of techniques to achieve that effect, such as by shaping the waveguides a certain way or by using variable-density foam. With the help of COMSOL Multiphysics and the Acoustics Module, our research team at B&C Speakers S.p.A. has taken a new approach by designing an acoustic lens in a waveguide that achieves the required phase coherence and produces a nearly perfectly planar

sound wave. Now a line array of speakers can work together as an extended sound source, which is particularly important for the high frequencies from roughly 1 to 20 kHz. The final

design of our waveguide is patented in Europe and patent pending in China.

Faster to Market with COMSOL

The power of modeling with COMSOL lies not just in reduced design time but in the information we have been able to gather for future designs. Beyond that, this finite element analysis allows us to evaluate quantities in system parts that we cannot reasonably access with instruments or by taking physical measurements. We learn so much about the behavior of a device that this invaluable wisdom can then be employed in the development of similar products and devices with deeper knowledge and awareness.

These days we seldom need more than one prototype. We save two months of engineering time that would have been involved in creating CAD models and trial-and-error

design refinements, and we ultimately get to market much more quickly.

We chose COMSOL Multiphysics because it is very user-friendly, provides for multiphysics couplings and is affordable — competitive software can cost five times as much for less application potential. We also were particularly impressed with COMSOL’s support to help us get the most out of the software. We achieved significant results in our first month, and it’s just been better ever since. n

Excellent Sound to Every Seat in the HouseModeling aids the development of a novel acoustic lens and dramatically shortens the time needed to find the best design.BY MATTIA COBIANCHI AND ROBERTO MAGALOTTI, B&C SPEAKERS S.P.A.

“We�were�particularly�impressed�with�COMSOL’s�support�to�help�us�get�the�most�out�of�the�software.��

We�achieved�significant�results�in�our�first�month,�and�it’s�just�been�better�ever�since.”

COMSOL saved B&C Speakers nearly two months of engineering time in the design of an acoustic lens that produces a nearly per-fectly planar sound wave.

1 1 www.comsol.com

With COMSOL Multiphysics® you are empowered to build the simulations that accurately replicate the important characteristics of your designs. The key is the ability to include all physical effects that exist in the real world. This multiphysics approach delivers results—tangible results that save precious development time and spark innovation.

Capture the Concept.

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A stator blade in the turbine stage of a jet engine is heated by the combustion gases. To prevent the stator from melting, air is passed through a cooling duct in the blade.