What’s the State of Nonlinear Simulation?

A key development goal of any machine-building project is to produce perfectly running, reliable machines that make high-quality products. By leveraging accurate virtual prototypes, seamless production can be ensured earlier in the development process to help assess and improve product profitability.

Heavy mobile machines consist mostly of production equipment working almost twenty hours a day, year on year, in diverse harsh environments, undergoing extreme loads and overloads. Especially diggers and loaders such as hydraulic excavators, wheel loaders, and backhoes, cater to multiple applications with use cases such as digging, trenching, loading, lifting, breaking, and ripping. Many times, these machines undergo non-standard uses where the machine is subjected to unplanned forces and moments as in the case of self-loading on a trailer, or a bucket hitting a dump truck body. This paper highlights the workflow process and simulation-driven methods to integrate multi-physics with Altair’s industry-leading solutions. The latest generation of Altair simulation tools can capture a wider range of vehicle systems and environmental interactions.

Radomes are used across multiple industries, including aerospace, defense, electronics, and telecommunications. When properly designed, the radome can actually enhance the performance of an antenna system. The proper selection of a radome for a given antenna can help improve the overall electromagnetic system performance by eliminating wind loading, allowing for all-weather operation, and providing shelter for installation and maintenance. Altair’s radome simulation solution helps to streamline the design of these complex components, ensuring performance while significantly reducing development time.

Learn how Altair Radioss™ Performs with AMD EPYC™ 7003 Series Processors

Medical stents are a lifeline for patients with cardiovascular illness and disease. Altair's solutions can speed up development time by satisfying the testing of variables virtually, allowing engineers to truly optimize the design and performance of medical stents.

Speaker design and analysis, especially for a more complex product, system, or component, often requires building multiple simulation models. The loudspeaker development process involves multi-physics and multiple sources in parallel, to multiple simulation runs for prototyping, testing, and validation. This results in separate models for nonlinear analysis of strength, thermal analysis and stiffness, noise, vibration, and acoustics. Even though each model isn’t always built from scratch, typically the use of different solvers for each attribute will require that models need to be converted from one solver format to another. This practice is not only time consuming but frequently error prone resulting in an inefficient use of engineering time.

The analysis of a design, especially for a more complex product, system, or component, often requires building multiple simulation models.

Block construction is a modern shipbuilding method which involves the assembly of prefabricated modular sections. Cross-sections of the superstructure are pre-built in a shipyard, taken to the building dock, then hoisted into position and attached. Block splitting and lifting schemes are largely devised after the ship design phase is completed, relying on empirical data and expertise to avoid costly and potentially dangerous failures during build-up. Advances in computer-aided engineering (CAE), however, now make it possible to plan ship build-up in the principal design phase, giving designers greater insights into block assembly process outcomes and reducing downstream risk through simulation.

Transformers’ windings experience mechanical loads from electromagnetic forces due to the currents they carry. Power transformers can suffer from high sudden short-circuit currents. These short-circuit currents are a significant threat, not only from an electrical but also from the structural integrity point of view. In this paper, coupled electromagnetic and structural mechanics simulations are carried out to evaluate short-circuit fault risks in a comprehensive and accurate way.

The Additive Manufacturing for Production survey conducted by TCT Magazine in association with Altair set out to understand the community’s desire and readiness for the much-promised land of series production using additive technologies. This collaboration between TCT and Altair was designed to understand the needs of the community in terms of current production capabilities, rate-limiting steps and areas of the technology that they believe needs improvement.

This paper presents a case study of a ship foundation optimized for DDAM early in the design phase to validate and optimize the structural integrity of a ship foundation subject to underwater shock conditions.

This article, featured in the October 2019 issue of NAFEMS BENCHMARK Magazine, chronicles the origins and legacy of OptiStruct, an early pioneer of simulation-driven design. Features quotes from Altair CEO Jim Scapa and other influential voices from the early days of Altair's history. Article originally published in Benchmark Magazine by NAFEMS, the International Association for the Engineering Modeling, Analysis & Simulation Community. Find out more at nafems.org.

Cost optimization is a driving force in all fields of industry, with every manufacturer competing to provide a cost-effective solution to the end customer. The paper addresses how to perform an early-stage design of components with emphasis on cost optimization and without consuming too much of a construction designer's precious time. The main objective of this paper is to generate a proposal for a car seat design, based on free size optimization and cost optimization using Altair OptiStruct commercial engineering software.

Topology optimization is an approach that optimizes the material distribution within a given design space, for a given set of loads and boundary conditions, to meet a set of performance targets. Using topology optimization at a concept level can help you achieve the best performing design while saving time by replacing costly design iterations.

Induction Motors (IM) are widely used in various industries. To ensure their speed control, IM will be supplied with pulse width modulation (PWM). This kind of supply, can impact efficiency of the motor and degrade its vibro-acoustic behavior, generating noise nuisance. To tackle these technical challenges and ensure best-in class acoustic comfort for users, it is necessary to design a quiet e-motors at the early stage of design. The first aim of this paper is to show a new method to reduce noise and vibration due to PWM supply of induction machine. The proposed approach allows the passive reduction of air-gap flux density harmonics in an induction machine. The second interest, is to show a new method to analyze the vibro-acoustic behavior of a PWM-fed IM. The method is fully finite element (FE) computation. Finally, the third interest of this article, is to compare noise and vibration results between the proposed FE method, magneto-vibro-acoustic coupling and measurements. Good agreement between measurements and computation will be shown.

This special report by engineering.com covers two of the most talked-about trends in the product design community today: Generative Design and Topology Optimization. These simulation techniques allow customers to design lightweight and performative parts using a simulation-driven design approach.

Many commercial aircraft are designed so that fuselage skins can elastically buckle below limit load and continue to operate safely and efficiently. This design regime makes for a very lightweight semi-monocoque structure compared to a non-buckling design. Therefore, predicting the local buckling, post-buckling behavior, and failures are critical to design and optimization of this kind of structure. The local panels buckle in a combination of compression and shear. Excess compression is redistributed to surrounding axial members (frames and stringers) and shear is continued to be carried by the buckled panels via tension parallel to the buckle waves. The compression redistribution and diagonal tension put special strength considerations on all involved structural components. This post-buckling behavior and the analysis method are both called intermediate diagonal tension (IDT).

Optimization software enables naval architecture and engineering firm to design a next-generation superyacht anchor arm that is less than half the assembled weight of its predecessor.

A company specializing in 3D printing relies on simulation to make tools for injection molding that are less expensive, lighter and better than those created with traditional methods.

In recent times there is a high demand for lightweight automotive components which will reduce oil consumption and emissions. The components that are under non-linear load conditions would need optimization techniques that would yield a design which satisfies all performance targets and at the same time maintains the process efficiency with respect to time and cost. The use of CAE tools such as Altair’s OptiStruct and HyperWorks allows engineers to explore various design solutions starting from concept level to matured design that meets multiple requirements simultaneously with due consideration of manufacturing methods that allows engineers to arrive at an optimal design and process.

To design and build an aerial ladder for a firetruck, the engineer needs to accurately determine the working loads the ladder will encounter. Some of these can be easy to interpret such as the weight of the firefighter in the basket at the end of the ladder, or the weight of the water being supplied to the nozzle. Other loads can be a little harder to quantify, such as how wind affects the ladder. There are several different ways to determine this effect, and two of those will be explored in this paper: the standard equation (ASCE 7-10), and CFD.

Optimal design methods involving the coupling of fluid and structural solutions are a topic of active research; particularly for aerospace applications. The paper presents a coupled fluid and structure approach to topology optimization using two commercial finite element solutions; AcuSolve and OptiStruct. A gradient based method is used to minimize the compliance of a structure subject to thermal loading. The optimal material distribution to minimize compliance is computed using the Solid-Isotropic Material with Penalty (SIMP) method available in OptiStruct. A volume fraction constraint is imposed in order to iteratively reduce the parts mass. Draw constraints are used to ensure manufacturability. The thermal loading is computed iteratively using a computational fluid dynamics (CFD) solution from AcuSolve. The optimization produces an innovative design which increases the heat rejection rate of the part while reducing the mass.

For large aerospace assemblies in finite element (FE) analysis problems, contact interaction between the surrounding bodies has to be established to simulate the load transferred between the components, like aircraft engine carrying bracket assemblies, spigots assemblies etc., and understand the effects of interaction between respective parts. In some cases, depending upon geometry of the assembly, the region of study may not be contact area but the stresses acting within the parts themselves. If there is no geometric or material non-linearity in such problems, a new contact formulation method known as Fast Contact can be used in these contact regions.

This paper gives a technical review and guidelines for positioning the current capabilities. Note that the following uses OptiStruct version v2018. There have been some changes to the discussed algorithms compared to previous versions. Generally, version 2017.2.3 can be used to reproduce all the presented results.

Snap-fits are ubiquitous engineering features used to quickly and inexpensively assemble plastic parts. The geometric, material, and contact nonlinearities associated with snap-fit problems can present modeling challenges. Quasi-static solutions with explicit solvers are commonly used to analyze snapfits; however, OptiStruct’s nonlinear solver now possess the ability to solve these highly nonlinear problems implicitly. The first part of this study discusses an effective approach to using OptiStruct for the implicit finite element analysis of snap-fits. Once an accurate simulation model has been created, engineers typically make design changes in order to achieve desired insertion and retention forces. The second part of this study details how HyperMesh morphing and HyperStudy can be used to optimize the snap-fit design, resulting in desired insertion and retention forces while minimizing mass and ensuring structural integrity. The approach documented in this report can reduce the design time, material use, and failure rate of snap-fits used in industry.

In an electric machine, the torque is generated by electromagnetic forces which also create some parasitic vibrations of the stator. These vibrations excite the mechanical structure on which the motor is fixed and generate sound. When designing the electric machine, this aspect has to be taken into account from the start since it depends on the harmonic content of the currents that feed the machine, on the shapes of the rotor and stator, and on the interaction of the electric frequencies with the natural mechanical modes of the structure. To simulate this phenomenon, a coupling between electromagnetic calculations and vibration analysis has to be set-up. Some optimization procedure can also be added in order to reduce the noise. In what follows, it is shown how Altair HyperWorks suite; specifically FluxTM, OptiStruct®, HyperMesh® and HyperStudy® products have been successfully used to perform a multi-physics optimization for noise reduction in a fuel pump permanent magnet motor.

This step-by-step tutorial details how to use RAMDO with HyperStudy and OptiStruct.

Reprint of Engineering.com article on OptiStruct as a structural analysis tool with built-in optimization capabilities

Altair RADIOSS* and Intel® Xeon® Scalable processors combine to provide an advanced solution stack for improved crashworthiness, safety, and manufacturability of automotive structural designs.

Altair OptiStruct* provides engineers and designers with a unified solution from concept to final design by leveraging advanced analysis capabilities and novel, optimization-driven simulation. In this process, the simulation time for one optimization iteration is a critical consideration, since it affects the computational speed and scalability of the entire design process.

In the development of new vehicles, the PSA Group aimed to detect Squeak and Rattle (S&R) problems before availability of physical testing. This led to a collaboration between PSA’s method development engineering team and Altair’s domain experts.

The reduction of run times up to 17X is a direct result of more powerful hardware and the more advanced algorithms in Altair’s latest software releases.

Additive manufacturing coupled with topology optimization allows the design-and-analysis and manufacturing iterations to be reduced significantly, or even eliminated. To ensure that the part will perform as simulated, a mid-stage validation is conducted on a standardized part before creating the final products.

To derive the natural frequencies and mode shapes of a given structure, the test Engineer has to decide on excitation positions that will efficiently excite all the modes of the structure in the frequency range of interest. Excitation positions are usually decided upon from experience or trial and error methods which can be time consuming and still not capture all of the modes in the selected frequency range. Using Altair HyperStudy and Radioss (bulk), Pre-test CAE analysis has been carried out to identify effective excitation positions before the commencement of modal testing, thereby significantly reducing pre-test lab time.

Automotive radars are becoming standard equipment on vehicles. Their purpose is to adjust the distance between vehicles and/or alert the driver when dangerous situations arise. Several antenna architectures are used to cover the different safety functions in complex bumper/car chassis environment where the side effects become more and more significant on the radar performances. Hence, automotive radar integration process becomes a very important topic. Weak radar integration will generate gain loss, high side lobes levels and angular errors. Those degradations will impact the radar range, the main radar axis (BSE) and the radar detection quality (resolution, ambiguity, discrimination).

Development tools and methods, such as simulation, are increasingly important to face and address the pressure of innovation. As an example, for successful new design methods and to show how simulation tools are used, Altair developed a virtual demonstrator based on a cobot application. This complex machine interacts with a human operator as the ultimate smart manufacturing equipment - to show how challenges in modern product design can be overcome.