Frazer-Nash Consultancy has, for more than 20 years, undertaken dynamic analysis and testing in order to solve a range of engineering problems associated with:
Clicking one of the above links will scroll the page to the relevant section.
Noise and Vibration
The control of noise and vibration is a critical aspect of the development of many products. In many cases, the objective is to reduce structural vibration levels and thereby avoid the possibility of structural failure due to fatigue. In other instances, the objective is to reduce vibration levels for passenger/operator comfort or to minimise environmental and radiated noise.
Working across a broad spectrum of industries including naval platforms, rail vehicles, off-shore structures and test rigs, Frazer-Nash uses advanced simulation tools to provide consultancy in a wide range of applications, including the following:
- Railway vehicle design
- Drivetrain design and whirl calculations
- Machinery raft design for submarines and surface ships
- Test rigs for automotive and aerospace applications
- Gas turbine enclosures and ducting
- Isolation of generator sets, compressors and pumps
- Packaging and printing equipment
- Naval acoustic signature prediction
- Acoustic tile and cladding design
- Sonar systems
Frazer-Nash has also developed and markets a dynamic modelling package, AVAS, which allows the user to easily compile a model of a dynamic system using a combination of discrete elements, finite element models and measured test data.
Go to Top
Acoustic Consultancy
Frazer-Nash provides acoustic consultancy services ranging from initial specification, though prediction and measurement to remedial engineering to solve existing problems.
Projects undertaken by Frazer-Nash have ranged from the measurement on internal noise levels within rail vehicles to the measurement of propagated noise from industrial installations and the subsequent generation of environmental impact statements.
Frazer-Nash has undertaken a number of projects to predict the underwater acoustic signature and target echo strength of naval platforms and systems. These applications make use of predictive software tools including Finite Element, Boundary Element and bespoke simulation packages. Projects have also been undertaken to reduce acoustic signatures by either structural design or the adoption of de-coupling tile strategies.
Frazer-Nash markets the Target Echo Strength prediction package, TESAC, for modelling naval applications.
Go to Top
Shock and Blast
Short duration, high amplitude loading is usually, but not exclusively, associated with military applications and weapons effects. Underwater shock and air blast are extreme load cases which provide the designer with considerable problems to overcome in assessing the the consequences of such loadings. Frazer-Nash possesses a depth of experience of predicting and mitigating weapon effects.
Predicting all the effects of mines and torpedoes on surface ships and submarines requires technologies capable of modelling a range of disparate phenomena including:
- The physics of an underwater explosion and the pressure pulse it generates
- The interaction between the pressure pulse and the vessel’s hull
- Transient dynamic response of the vessel structure
- The performance of shock isolation systems
- Damage mechanisms
Frazer-Nash uses methods such as large hydrocode simulations to describe the complete shock event. Advanced non-linear finite element systems are used to predict structural response and failures. Frazer-Nash also uses its own naval shock software product, FNSHOCK, to rapidly predict the non-linear response of equipment and mounting systems, providing early definition of the system performance at the initial stages of any project.
Impact and Crashworthiness
Impact represents the main short duration, high amplitude load scenario other than shock and blast. In vehicle structures, impact simulations are broadly considered under the banner of crashworthiness. Frazer-Nash has performed crashworthiness impact simulations on a number of rail vehicles. Similar non-linear modelling techniques have been adopted to simulate other events ranging from dropping containers to bird strike on a leading aircraft wing.
The analysis of impact events is not constrained to mis-handling and fault conditions. Frazer-Nash has also helped to design an efficient hammer drill by means of the modelling and optimisation of the impact event within the drill.
Mobility of Vehicles
Frazer-Nash has considerable experience in assessing the mobility of military vehicles. The company uses a mixture of assessment techniques from paper based comparison to the defence standard to computer modelling using its own in-house developed tools or military standard tools such as the NRMM2. The company also has extensive experience of other vehicle dynamics analysis including: rollover and handling prediction, chassis stressing, reliability predictions and noise and vibration exposures of personnel.
Go to Top
Transient Dynamic Response
The dynamic response of a structure or system can often generate internal loads considerably larger than an equivalent static load case. In order to maintain structural integrity at all times, it is necessary to quantify the stresses developed in a structure when time-varying loads and displacements are applied to it.
Frazer-Nash uses a variety of techniques to predict the dynamic response of structures and systems. The dynamic solution technique within the general purpose finite element code ABAQUS has been used to predict the structural integrity of nuclear components under pressure transients. Frazer-Nash’s discrete element modelling package GENDYN provides the platform for analysing the roll-over characteristics of road tankers. Where appropriate, we can also develop bespoke dynamic simulation software to predict the response and loads of non-linear systems, an example of which is the complex interaction of structures during the release of air-launched missiles from air weapons carriage equipment.
Types of applications considered include:
- Start-up and run-down on drive trains
- Pressure transients on pressure components
- Tanker roll-over and mobility studies for off-road vehicles
- Missile release
Go to Top
If you would like further information about our services or products, or want to know if we can assist you in a particular project, please complete the form on the Contact Us page.