Sound & Vibration Research Group

Focus

The Sound and Vibration Research Group (SVRG) is situated in the Department of Mechanical and Mechatronic Engineering at the University of Stellenbosch. The SVRG has established expertise, equipment and laboratory facilities to conduct research and investigations into noise and vibration problems for industry as well as the public sector. Our primary field of research is associated with human response to sound and vibration where, in particular, seating dynamics and sound quality are investigated.

Objectives

  • To establish a centre of expertise in sound and vibration measurement, analysis and assessment with the associated measurement equipment and software tools to contribute to the international research arena.
  • To train engineers with the necessary skills and knowledge to work in the field of sound and vibration research and to serve industry as specialists in the field.
  • To assist South African companies in solving sound and vibration problems to ensure that their products are more competitive and that their workforce enjoys a safe and healthy working environment.

Current Research

Vibration and Acoustic comfort on the polar supply and research vessel - S.A. Agulhas II

Vibration and Acoustic comfort on the polar supply and research vessel - S.A. Agulhas II

As part of an international research consortium between the Universities of Aalto and Oulo, Aker Arctic, Det Norske Veritas, Rolls Royce, Wartsila and STX Europe the SVRG performed vibration comfort measurements on board the SA Agulhas II, the new polar supply research vessel. The SA Agulhas II was put to the test during two days of ice-breaking operations in the Bay of Bothnia in Finland during ice-trails as well as a 76-day voyage between Cape Town and Antarctica. Sound levels and vibration comfort will be determined in conjunction with exterior ice conditions and ice-loads on the ship hull in an on-going research project which enables a unique comparison between Arctic and Antarctic conditions.

Psychoacoustics of Electric Vehicle Sound Signatures

Psychoacoustics of Electric Vehicle Sound Signatures

The SVRG has been involved in the field measurement of the drive-train noise and vibration of electric vehicles which to date include the Joule electric vehicle prototypes (Optimal Energy Pty. Ltd.) and the Nissan Leaf. At present the psychoacoustics and enhancement of quiet electric vehicle sound signatures is being initiated within a post-graduate student exchange with the University of Applied Sciences in Ingolstadt, Germany. This work aims to contribute to the methodology of psychoacoustic assessment of electric vehicles and the sound queues that add to driver exhilaration and safety.

Teaching and Learning through Music

Teaching and Learning through Music

A new laboratory learning experience is being designed and evaluated for third year Mechanical and Mechatronic Engineering students of the Vibration and Noise 354 course. The learning opportunity will utilize students' knowledge and experiences of music to captivate their interest and to teach them the principles of the natural frequencies and modes of beams. A musical instrument is being created from a Christmas tree structure comprising of clamped-free beams of different lengths. The beam dimensions are selected such that they have natural frequencies which correspond to the eight notes of a musical scale.

Areas of Expertise

  • General noise and vibration measurement, analysis and assessment to reduce overall noise and vibration levels, troubleshoot specific problems and investigate the application of advanced methodologies, such as vibration monitoring, to reduce maintenance and operating cost.
  • Modal analysis, both experimental and using finite element models to verify structural response.
  • Signature testing and order analysis on rotating machines.
  • Measurement and assessment of industrial noise and vibration to ensure healthy and safe working environments.
  • Assessment of automotive NVH (noise, vibration and harshness) according to national and international standards.
  • Environmental testing of components and structure for vibration endurance.
  • In-situ measurements of sound for playback in jury panel evaluations and the calculation of metrics to assess the sound quality of products and vehicles.

The Members

Dr Annie Bekker

Director

Prof Wikus van Niekerk

Member

Brendan Boulle

Test Engineer

Keith Soal

MASTERS STUDENT: Human Vibration Comfort on the S.A. Agulhas II

Kim McMahon

MASTERS STUDENT: Human Vibration Comfort on the S.A. Agulhas II

Hannes Swart

MASTERS STUDENT: Psychoacoustics of Electric Vehicles

Brendan Potgieter

MASTERS STUDENT

  • T +27 21 808 4957

Equipment

  • Various LMS SCADAS data acquisition systems
  • Dynamic Seat Testing Facility for vertical vibration excitation of seated occupants.
  • Accelerometers (both modal array ceramic shear and DC-type sensors)
  • Seat-pad tri-axial accelerometers for whole-body vibration measurement
  • Electro-dynamic actuators (small, medium and large)
  • Modal hammers, displacement transducers and force transducers
  • Sound level meters with frequency analysis
  • Binaural head simulator
  • Binaural head set
  • Half-inch pre-polarized free-field condenser microphones
  • Psychoacoustic jury testing hardware

Previous Projects

  • Ford Motor Company: Metrics to assess dynamic seat comfort and sound quality investigations.
  • Gautrain: Ground-borne vibration impact assessment.
  • Optimal Energy Pty. Ltd.: Analysis of electric motor sound and vehicle level noise and vibration benchmarking.
  • Square Kilometre Array (SKA) Africa: Modal testing of radio-telescope antennae structures.
  • SA Agulhas II: Assessment of sound and whole-body vibration comfort.
  • South African Breweries Ltd.: Measurement of vibration on a kiln-fan assembly.
  • VeeCraft Marine: Troubleshooting of a whining noise in a harbour vessel passenger cabin.
  • Kumba Iron Ore: Compliant mounting of a sieve shaker.

Contact Us

Dr Annie Bekker

Director: Sound and Vibration Research Group

  • Department of Mechanical and Mechatronic Engineering
  • Mechanical Engineering Building, Office M617
  • University Stellenbosch
  • Cnr. Banghoek & Joubert Street, Stellenbosch, 7602
  • www.svrg.sun.ac.za