In some cases, it’s beneficial to run the physics sequentially.” “So you may start the simulation in CFD, then use the result as input for your structural analysis.
“In that case, even if the stresses are high, the associated deformation of the surface is minimal,” notes Bjorn Sjodin, vice president of product management, COMSOL. Technically, the scenario involves two types of physics: fluid flow (to compute the airflow) and structural (to account for the building’s surface). Take another example: the stresses on the side of a building due to strong winds. The above Moldflow results show: the fill time (flow), frozen layer fraction (phase change), temperature (cavity and core) and von Mises stresses (core) of a water pump housing model and the mold assembly.Images courtesy of Autodesk. “If it’s freezing outside, in other words, the temperature around the glass is extremely low, then the temperature gradients inside the glass and outside become important to study, because the glass will break a lot sooner,” Lin adds.Īutodesk Moldflow, targeting the injection molding industry, is inherently multiphysics. If you want to figure out the point at which the glass will break due to hot water temperature, typically you don’t need to set it up as multiphysics, because the temperature’s effect on the expansion behavior in this kind of scenario is not crucial.”īut the same phenomenon under a slightly different environment may make multiphysics a must, not optional. For example, take the act of pouring hot water into a glass. Ted Lin, general manager of AMPS Technologies, says, “Most experienced users can tell right away if a problem needs multiphysics or not.
How can you tell if something truly demands multiphysics? When is it acceptable to simulate the different physics sequentially? When is it important to compute them together? Partly, the wisdom comes from industry experience and engineering tenure, neither of which a software package can teach you. Whether it’s saline fluid flow inside a medical device or airflow around a race car, if you can get the answer you need by reducing the phenomenon to a simpler study, then setting it up and solving it as multiphysics is an excessive use of resources, both in hardware and in manpower. Perhaps what’s more important is to identify the scenarios where multiphysics treatment is truly warranted. Shown here is the multiphysics analysis of a microprocessor chip. IronCAD integrated the multiphysics solvers from AMPS Technologies, enabling IronCAD users to set up and run multiphysics analyses from the CAD modeling environment. Greg Fallon, vice president of simulation at Autodesk, says, “I don’t see the distinction whether you solve sequentially or simultaneously, because in the end, you’re dealing with various types of physics.” The simulation job can be sequential or simultaneous.” Similarly, Nicolas Tillet, product portfolio manager, Dassault Systèmes SOLIDWORKS, says, “Multiphysics involves different types of physics.
In this context, both the sequential and simultaneous solving of multiple disciplines of physics are multiphysics simulations.” More specifically, any time data is shared between solvers from different traditional disciplines (computational fluid dynamics or CFD, finite element analysis or FEA, electromagnetics, etc.), an engineer is performing multiphysics simulation. In the view of Chris Wolfe, lead product manager of multiphysics at ANSYS, “Multiphysics simulations happen whenever engineers need to understand the effects of multiple physics on real-world products. But if, due to the limitation of the software or out of your own choice, you simulate the heat buildup inside the engine chamber first and then use the result as input to figure out the component’s expansion, is it multiphysics? If you use a simulation package that lets you simulate the component’s expansion (structural physics) and heat propagation (thermal physics) simultaneously, the job is indisputably multiphysics. Suppose you’re simulating how an engine component expands in response to heat buildup during a car’s drive.