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The Sebert Trillingstechniek consultancy services focus on the fields of shock, noise, and vibration. The emphasis lies on the integration of requirements related to the engineering phase of a product. The rule ‘prevention is better than cure’ applies also here.
Operational, functional, governmental, and environmental requirements are normally taken into account during the design of a product. However, shock, noise, or vibration requirements are frequently an exception to the rule and are frequently used to balance the budget. A budget that in the long run, will be disappointing.
Some of the reasons that might delay taking on these requirements are the level of difficulty, cost, or the amount of effort required. However, it appears that a reduction of costs can be achieved with an integral design philosophy by incorporating the shock and vibration requirements directly at the beginning, particularly for large quantities. The additional costs represent only a fraction of the total engineering costs while the savings on materials, service costs, and packaging could rise to as much as 15%. In some instances, transport volume and costs can be reduced by as much as 70%.
S2T specialises in the integration of shock, noise, and vibration requirements for the design of all kinds of products and installations. This specialisation ranges from simple valves to power plants, from HVAC-installations to very complex control panels, and includes computers and the like. It is customary for S2T to work and collaborate closely with the contractor's engineering team. S2T provides support for designers, draughtsmen, and production departments with guidelines and instructions for the integration of typical design requirements. Taking shock, noise, and vibration requirements into account (without ignoring other requirements) is a very cost-effective process.
Each shock test becomes a non-destructive test and every shock analysis guarantees just enough shock resistance. A vibration analysis of, e.g. a control panel, prevents fatigue failure or damage during a vibration test. At the component level, (prototype) vibration and shock tests are usually more cost-effective than analyses. However, component design is taken into account when considering these aspects. S2T has an extensive test facility to accommodate all your dynamic and static tests. S2T has also many years of experience with respect to (structure-borne) equipment noise reduction and the acoustics of ships. The high structure-borne noise levels of machinery cause high airborne noise levels and these can require extensive and expensive additional measures. A reduction of structure-borne noise levels of 15-25 dB is achieved, resulting in an equal gain in airborne noise levels
Noise predication and results
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Sebert Trillingstechniek carries out noise predictions for ships. For instance, certain noise levels were predicted for the sleeper cabins on a ship caused by a cooler and RO-unit located directly below these cabins. Based on previous design information, the RO-unit was decisive. S2T was responsible for the shock and noise aspects of the new RO-unit design during the engineering phase. The structure-borne noise level improved considerably.
In the diagram on the right, the upper line indicates the measured structure-borne noise level (dB re 1μm/s²) of the previous RO-unit. The second line is the measured structure-borne noise level of the new design achieved by S2T. This line is 10-20 dB lower while using similar machinery on the base frame. The second line from the bottom is the predicted airborne noise level in the cabins above the RO-unit (total 62 dBA - dB re 20μPa). The bottom line is the airborne noise level in the sleeper cabins. Approximately 45-48 dBA, a gain of ~16 dB is measured in three positions. This gain is primarily due to the lower structure-borne noise of the RO-unit. A resilient mounting arrangement developed by S2T also contributed significantly to these results and eliminated the need to make any additional adjustments to the acoustics of the cabins.
The additional engineering costs were approximately 1.7% for noise, and 3.5% for shock, representing the total engineering cost of eight RO-units. The total engineering costs represented approximately 8% of the unit price, i.e. only 6.4% of the unit price was related to the shock and noise aspects. Due to a more efficient design, the additional measures implemented in the design of the RO-unit for shock and noise did not influence the production costs
Analyses and optimisation studies
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S2T carries out strength, stiffness, shock, and vibration analyses for control panels, complex structures and the like.  The primary purpose of these analyses is focused on compliance of the requirements and secondly, to optimise the design for mass production and cost. A good shock design requires an optimal application of material (minimum mass), material properties, strength, stiffness and the like.
Together with the Contractor, S2T also weighs production options and costs to minimise the total cost of an item. A basic rule in shock design is to avoid all that superfluous materials. Non-existing components or parts do not need to be analyzed, drawn, or produced and hence costs are saved. Stresses are reduced during a shock test resulting from the lower masses, and above all, non-existing items cannot fail during a shock test.
The customer is of paramount importance to S2T. Therefore, S2T strives for optimal customer services. Do you have questions regarding shock, vibration, and noise problems? Sebert Trillingstechniek can help you. S2T has at your disposal with almost 40 years of sound knowledge and experience in the field of shock, noise, and vibration testing. S2T has her own test facility for shock, vibration, fatigue, and other dynamic and static tests. S2T also carries out measurements onsite. S2T will solve all your shock, vibration, and noise problems in a professional manner.
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