Tips & Tricks

SEA - Display energy flow for a subsystem in complex models

In a complex SEA model made out of several subsystems, VA One can be used to display the energy flow to a particular subsystem in a couple of steps, this helps to understand how the energy flows to a receiving subsystem in order to define noise control strategies. One of the steps is to isolate the junctions associated to this subsystem, this will also help to understand / verify the connectivity of the model.

SEA - Virtual Transmission Loss

In a complex SEA model made out of several subsystems, using VA One is possible to extract the transmission loss (TL) of one or various subsystems in a single step. Transmission loss of partitions e.g. walls, floor, windows, enclosures have been studied theoretically and experimentally over many years. Partitions are often inhomogeneous, non-uniform, comprise combinations of different materials, have indeterminate boundary conditions and are subject to sound complex fields. Surprisingly the sound transmission behavior of many plane partitions is quite well represented by a simple model which ignores the boundaries. Sound transmission loss can be used to correlate the vibro-acoustic behavior of simple and/or complex systems.

VA One - FE or SEA- How to map trim thickness for sound package representation

Sound control treatments / Trim ,(e.g. headliners,hood liners, dash panel and floor isolators, etc) have complex shapes with variable thickness, sometimes only CAD parts are available. How can I use this data to create noise control treatments (NCT) in FE and/or SEA models with variable thickness?. In this article it is shown how to create a variable thickness noise control treatment with VA One for SEA and/or FE purposes at the same time. A multiple noise control treatment (MNCT) is created for SEA purposes and multiple FE Faces with the mapped/discrete thicknesses are created for FE purposes,

Find dominant path in SEA models

Statistical energy analysis (SEA) computes the flow of vibrational energy between coupled subsystems by applying principle of conservation of energy. Using conservation of energy power balance equations which govern response of a system. Since it is based on energy flow, path analysis is straight forward. In this article it is described how to extract the dominant path in a complex model using SEA and VA One . As a result the subsystems in the dominant path are displayed in the 3d window (All other subsystems are hidden).

Process optimization: the future of numerical simulation software

Optimization is becoming a very popular word. However, what does it mean and what does it involve? The goal of this e-tip is to give some keys about optimization concepts and its use in process optimization. In a first stage, we will describe the type of optimization problems that could be solved and in a second stage, the principles and algorithms will be presented. Finally, advantages and drawbacks of the different methods and algorithms will be addressed, with respect to the different types of optimization problems which can be solved.

Casting simulation: from prototype to performance

Passenger safety in cars, planes and other transportation vehicles is an ethical obligation, a legal issue and a technological challenge. Simulation is a well implemented tool in order to test the behaviour of a car body during crash. The models, including rapid deformation and rupture, are sophisticated and reliable. Currently, most properties used in such simulations correspond to homogenous and defect free materials. However, cars are manufactured before being crashed. And manufacturing routes such as casting, but also stamping, forging or welding, do not provide defect free and homogeneous materials.

Parallel processing

“To pull a bigger wagon, it is easier to add more horses than to grow a gigantic horse.” This paraphrased quotation nicely expresses the basic concept of parallel processing. The speed of sequential computers has been doubling every eighteen months, according to Moore’s law. However, at any given time, that speed is limited by the state of the art in integrated circuit design and manufacturing. To circumvent that limitation, it is possible to split a given computationally intensive task among multiple processors working simultaneously.

The manufacturing of sand cores

The manufacturing of iron, steel and non-ferrous castings is achieved using a variety of casting process designs, and most of these involve the use of sand cores which form the internal shape of the casting. A good quality casting requires a good quality core. Dimensional stability, uniform density, strength, hardness and permeability are some of the characteristics that need to be controlled. A good core must have suffi cient strength and hardness to be handled and to resist during the pouring of liquid metal. Suffi cient permeability is also necessary for the escape of gases generated during the casting process. The diff erent manufacturing processes and some of the issues related to core production will be discussed here.

Critical issues in modelling investment casting

Reduce part development lead-times by a better knowledge of process and an early confi rmation of metallurgical capabilities is one of the main topics for investment casting technology. Numerical simulation is one of the major tools which can be used to face this goal. This e-tip illustrates a simulation methodology usable to optimize a casting design in an effi cient and rapid way.

FLEXlm protection file system

ESI group needs to license, manage and track a variety of licensing options, platform and product dependencies. FLEXlm is one of the only software that is up to this task. A simple, shrinkwrapped license management product would not be powerful and flexible enough to license all ESI products.