It’s Sunday afternoon and I am pottering about in the kitchen cooking a Sunday roast. From the living room, I can hear my two children bickering about what they are going to play with. “Why don’t we play with Lego?” says the one. ”I want to play superheroes!” says the other. My husband is, unsuccessfully, trying to reason with them and get them to play together while at the same time sorting some paperwork. This is a typical weekend day for us. Everyone busy, on their own timescale, you could say, but trying to be together as a family. After all, isn’t that what the weekend is all about?
“Lunch is ready” I call from the kitchen, “time to set the table”. They both rush in, still continuing to talk over each other about the preferred game. We finally, sit around the table and the conversation turns more amiable. Now, we are talking about passing potatoes and veg and who wants which part of the chicken. Everyone agrees, the food is yummy!
In physics, as in life, not all processes are on the same timescale. In conjugate heat transfer (CHT) simulations that involve fluids and solids, they can actually be very different. Typically, fluids have fast transients and solids show slow temperature changes for longer periods. Accurate prediction of temperatures in solid components require long simulation times and it is essential for predicting thermal fatigue life. Such cases are turbine blades or engine blocks over the course of a typical use cycle. The challenge in these cases where we have large differences in time scale between fluids and solids is the large, almost prohibitive, computational cost.
The little Sunday routine of ours and its effect on our family life makes me think of this very issue and the new single simulation multi-timescale workflow for CHT introduced in Simcenter STAR-CCM+ v13.06. The new workflow introduces various features with the aim to eliminate the use of complicated macros. In Simcenter STAR-CCM+ v13.02 we introduced dedicated reports for fluid and solid and in Simcenter STAR-CCM+ v13.04 we improved the definition of Total Heat Flux to account for cases where radiation is turned on the fluid. And in this version, Simcenter STAR-CCM+ v13.06, we are introducing two additional very important features, an explicit mapped contact interface and solver specific stopping criteria.
The new explicit fluid-to-solid mapping links the different timescales by passing the right physical quantities, taking radiation and other thermal effects into consideration. In the case of transient flows, an efficient averaging mechanism can be employed on the thermal properties. It also enables coupling with the Finite Element solid energy solver also released in Simcenter STAR-CCM+ v13.06. This mainstreams multi-scale CHT simulations and eliminates user error.
Related to this, the latest version also provides new solver-specific stopping criteria to aid simulations that run multiple solvers consecutively. Previous stopping criteria were shared by solvers, forcing users to write lengthy macros to change the values when switching solvers. Simcenter STAR-CCM+ v13.06 moves the ownership of stopping criteria from the user to the solvers and introduces fixed stopping criteria in a “delta” sense enabling automation and consecutive multiple solver iterations. This means that in a multi-timescale simulation the fixed number of iterations will run will run without manual interaction, every time the continua is activated.
The case used here to demonstrate the functionality is an exhaust manifold with the heat shield included. It’s a case of heating up the engine up to a certain temperature. Those simulations can take up a lot of time as the solid might take a few minutes to heat up while the fluid, if run transient, needs a time step of about 1e-4 to converge. In this case for simplicity we run the fluid as steady.
Use of solver specific stopping criteria takes advantage of the faster convergence of the fluid as simulation progresses, so fewer exchanges are needed. Several stopping criteria are used to trigger a rerun of the fluid. What's particularly nice with this set-up, is that the expensive fluid part of the simulation is initially using more iterations but as the simulation progresses the number of fluid iterations required to converge to the monitor-based stopping criteria is significantly reduced. It is obvious that the new solver-based stopping criteria provide the user with easy access to tools that enable speed up of expensive CHT simulations.
In the animation you can see the temperature changes with time. The vertical lines signify a fluid run. Exchange is happening through the explicit mapped contact interface when the solid temperature shows a certain delta of temperature. This way we make sure we don’t exchange when it is not needed, and the explicit mapped contact interface takes care of the averaging ensuring accurate passing of information either side.
Which brings me back to my family lunch on that beautiful Sunday afternoon. Makes me think of how a family lunch can bring us all together, just like the explicit mapped contact interface, and how we all need to have our very own control of our time. Lunch is now finished, and we are tidying-up. As we are finishing putting the plates away I can hear them laughing. “Let’s make superheroes with Lego” they say to each other and wander off happily.
Have you ever wondered about the physics of a roller coaster?
Or thought about how strong the bolts and joints have to be to withstand the impact of the racing cart. They better be strong if people are ridding them, otherwise, there will be life-threatening consequences. The same goes for the vehicles we drive. The bolted joints are exposed to dynamic structural loads and constant vibrations daily. One loose joint could not only be extremely costly but more importantly, could put someone's life in danger. That is why it is of the utmost importance to develop safe, reliable joint solutions. This is nothing to be concerned about because innovative technology is helping many companies determine the likely causes of joint failures and help secure them.
We have established that joints are important. That is why Nord-Lock made it their goal to "provide maximum security for bolted joints." As mentioned above, innovative technology has made it so we reduce the reliance we have on physical testing. Nord Lock made this possible by adopting Simcenter 3D and NX Nastran to stay ahead of the game. Using Simcenter 3D motion software, Nord Lock is able to analyze stress states such as deformation, movement in joints, provide precision and reliability of NX Nastran solver and management of CAD. These simulations allow Nord-Lock to gain insight and validate internal business rules. For example, Simcenter is used to investigate failure situations. The weakness in joints generally have two main sources:
Spontaneous loosening caused by vibrations and dynamic loading effects
Slacking from preload loss as a result of settling and relaxation
Nord-Lock turned to digital technology as an alternative to physical testing which has helped them test both giant and small structures.
"We particularly appreciate the teams business expertise, their extensive knowledge of THE software and their availability." -Zouhair Chaib
The latest release will help you increase system simulation efficiency through a seamless process integration, maximum modeling accuracy and easy access to digital twins.
Among many other enhancements, major development efforts have been put to help you address 5 key applications:
Vehicle systems and components performance engineering
Aircraft systems performance engineering
Discover Simcenter Amesim 17 in a nutshell:
Let us walk you through the main new capabilities.
Import of electric motor characteristics from Simcenter SPEED
Expansion of air conditioning system capabilities for battery cooling
Battery thermal run-away modeling and battery pre-sizing tool
Hybrid and electric vehicle model templates
In 10 years, hybrid and electric vehicles could represent about half of the automotive fleet. That’s why there have been major development efforts to support electrification. With the newest version, you can automatically import motor characteristics from the Simcenter SPEED electric motor design software and assess electric powertrain performance early in the development cycle.
To safeguard proper battery operating conditions, you can link the battery cooling system with the air conditioning system. The new brazed plate heat exchanger component helps you easily check the capability of the cooling system to manage the battery and cabin thermal operation.
Further, for electric and hybrid vehicle design, Simcenter Amesim 17 comes with ready-to-use templates to assess consumption, range, cooling and drivability. These templates provide a good starting point for vehicle electrification projects by delivering parameter consistency and detailed internal combustion engine, transmission, electric drive, battery and cabin cooling subsystems models.
Upgraded signal bus capability and statechart management
Cooling system functional components
Real-time compatible components in the fluid component design libraries
Tunable parameters for FMI 2.0 export
In the context of software-intensive products, Simcenter Amesim 17 offers new plant modeling capabilities to support controls design, validation and calibration. For instance, the signal bus feature has been reworked to optimize central processing unit (CPU) performance and the user experience. When modeling control units, you can now easily create, edit and manage supercomponents containing statecharts.
Additionally, the release comes with real-time compatible components for automotive cooling system design as well as for hydraulic, thermal-hydraulic and pneumatic component design.
Vehicle systems and components performance engineering
Exhaust calibration tool including optimization features
Engine manifold design study through full coupling with Simcenter STAR-CCM+
Kinematics and Compliance data generator
Cam profile definition from the valve lift
Hypoid gear component
Extended modeling capabilities for vane and gerotor pumps
For conventional and hybrid vehicles, a broad set of new capabilities in Simcenter Amesim 17 will help to tackle critical challenges, such as the real driving emissions (RDE) or Worldwide harmonized Light vehicles Test Cycles (WLTC) standards. Among them, the exhaust calibration tool now enables accelerated test data import, batch processing and automated optimization of model calibration.
Moreover, by coupling Simcenter Amesim with Simcenter STAR-CCM+, you can efficiently run an engine design study for operating points of interest. This allows you to assess intake line acoustics or the impact of manifold geometry on performance.
Aircraft systems performance engineering
Intuitive and detailed jet engine performance analysis
Fuel systems and flight dynamics coupling
Fuel tank mapping from CAD
Model templates for landing gear and flap systems
In support of the aerospace and defense industry, Simcenter Amesim 17 offers unique virtual integrated aircraft (VIA) capabilities to frontload system integration, electrify propulsion systems and streamline jet engine design. It enables rapid modeling of compressors and turbines with variable geometry as well as assessing mixture composition corrections and degradation performance.
Since fuel represents a large portion of the aircraft weight, it is critical to understand its impact on handling qualities. You can now quickly assess the aircraft mass balance and trajectory while accounting for its tight coupling with the fuel system.
Moreover, Simcenter Amesim now enables you to generate fuel tank maps from CAD geometry. Therefore, you can extract the fuel inertia tensor for coupling with flight dynamics, and tank wet areas for thermal management optimization.
Embedded Simcenter STAR-CCM+ technology for enhanced cabin air flow modeling
Ego vehicle modeling for ADAS/AD validation with Simcenter Prescan
When I first joined Siemens PLM Software, Dirk De Vis, Vice-President of Simcenter Engineering and Consulting services, explained me the different types of projects his engineering team executes. Before anything else, he put a glass of water on the table and slammed his fist on the table. Obviously, the water was disturbed, splashing over the edge of the glass. My first notion of the source-transfer-receiver approach…
As you understand from this example, a noise and vibration issue originates from a source, which is transferred via one (or more) transfer paths to a given receiver location. Transfer path analysis, or in short TPA, is a methodical approach to vibro-acoustic design. It enables you to quantify the various sources and their paths, figure out which are important, which contribute to the noise issues and which ones cancel each other out.
The source-transfer-receiver concept nor TPA approach are new. All over the world, automotive engineers apply it to investigate and understand a product’s noise, vibration & harshness (NVH) performance. Different TPA methods are available: test-based and/or simulation-based. The preferred methodology depends on the structure, single or multi-reference sources, and the stage of the development.
Although, traditional approaches to transfer path analysis such as: airborne loads estimation, acoustic source quantification, structure-borne loads estimation, multi-reference TPA and energetic power-based ASQ are still relevant and widely employed, new methods are being developed.
Faster results, more accurate, better product refinement, and as a consequence faster troubleshooting at reduced cost, our customers are on top of their game. They apply TPA to benchmarking and target setting, vehicle development and pass-by noise engineering. Additionally, these new TPA methods empower suppliers to predict how their system will perform not just in one vehicle, but in a whole series of different variants. Component-based TPA using blocked forces is a prime example of how new TPA methodologies put the relationship between OEMs and suppliers in a completely new perspective.