This study quantifies whole-body vibration on a range of mine machinery typically used in a South African open cast mine. The ISO 2631-1 (1997) standard was used in the computation of weighted root mean square (WRMS) and vibration dose values (VDVs) whereas the ISO 2631-5 (2004) standard was used in the computation of daily static compressive stress (Sed) and R factor values. Two methods have been used to evaluate the whole-body vibration on a wide range of equipment used in an open cast mine. There are two main parameters for each of the standards. The ISO 2631-1 (1997) standard utilises the daily exposure A(8) and VDV, whereas the new ISO 2631-5 (2004) standard methodology uses the parameters Sed and R factor. ISO 2631-1 (1997) is poor in taking account of transient shocks. This led to the development of ISO 2631-5 (2004). Signals were therefore generated in the laboratory to further explore the parameters of the two standards. Vibration signals of more-or-less steady periodic processes can be approximated by superposition of sinusoids. To investigate the effect of shocks on the WBV response parameters used in the two standards, a series of investigations were conducted using very simplified simulations to capture the essential nature of various operational conditions, and qualitatively explain the trends in the response parameters. Pure sinusoidal data was first generated without shocks and investigated. Subsequently, sinusoidal signals with higher amplitudes were generated and investigated. Sinusoidal signals with increasing shock amplitude up to and exceeding the crest factor of 9 based on ISO 2631-1 (1997) were generated and analyzed. Finally, simulated data with different shock magnitude for five typical example cases were then generated and analyzed. The pure sinusoidal data was artificially generated using the signal generator at different amplitudes and frequencies, which are similar to field observed frequencies to enable numerical investigation of parameters to be carried out. A subset of the data was selected based on frequencies and amplitudes obtained on the field so as to have a representative data set on which investigations were carried out. The two parameters of the two standard methodologies were computed using simulated sinusoidal signal data. The trends in each of the parameters corresponding to each of the standards were monitored using various scenarios obtained by varying the signal parameters and compared against each other. There was approximate proportional correlation between the two parameters (VDV and Sed) with varying degrees of slope for each scenario. The Sed and VDV parameters are plotted on the x- and y-axes respectively. The graphs with slope greater than 1 corresponded to signals with low or no shock content; whereas the graphs with slope less than 1 corresponded to high shock content. The shock parameters (VDV and Sed) corresponding to the ISO 2631-1 (1997)and ISO 2631-5 (2004) standard methodologies were computed from field data and compared to see if the same trend obtained from the numerically obtained sinusoidal signals could be validated. It was found that the there was a gradual band correlation with slope less than 1 between the VDV and Sed parameters corresponding to signals of high shock content thereby validating the numerical findings. Since little or no extensive epidemiological studies have been carried out on the new methodology; it is recommended that more epidemiological studies be done to determine the exposure action and exposure limit values with respect to shocks in the Sed parameter for the new ISO 2631-5 (2004) standard methodology. It is advisable that caution is taking when using the new ISO 2631-5 (2004) standard methodology in evaluating whole-body vibration measurements until the limits are properly established. It is suggested that the new standard be used along with the established ISO 2631-1 (1997) standard methodology. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Mechanical and Aeronautical Engineering / Unrestricted

<p>To produce competitive vehicles, their comfort is one important issue to take into account during the development process. The aim of this Master Thesis is to develop an on-line comfort evaluation tool in order to improve research and education in the field of vehicle comfort at the division of Vehicle Dynamics at the Royal Institute of Technology.</p><p>Based on ISO standards concerning comfort an on-line evaluation tool has been developed using DASYLab, which is a software that allows creation of acquisition, control, simulation and analysis tasks.</p><p>The developed tool has been evaluated by performing measurements of a VOLVO V40 equipped with sensors. Different sorts of surfaces and driving conditions have been investigated, and from this investigation one can conclude that the comfort tool works properly.</p>

Motoristas de ônibus estão diariamente expostos a vibrações de corpo inteiro (VCI), o que os submetem a riscos de desenvolver problemas de saúde relacionados a essas condições. Numerosos estudos focados em quantificar e identificar os riscos a que os motoristas estão expostos foram desenvolvidos nos últimos anos. Porém, pesquisas mostram que muitos fatores influenciam na transmissão da vibração ao corpo humano. Estradas podem ser consideradas um fator importante na determinação da exposição à VCI que um motorista de ônibus recebe. Nas áreas urbanas, os tipos mais comuns de estradas encontradas são: asfalto bom, asfalto irregular, paralelepípedo, estrada de chão, estradas esburacadas, entre outros. O objetivo deste estudo é determinar se diferentes tipos de estradas, encontradas em vias urbanas, provocam diferentes respostas de VCI; e determinar a influência de cada tipo de estrada na exposição à VCI de acordo com a norma ISO 2631-1 (1997). Dois motoristas diferentes guiaram o mesmo ônibus urbano sobre diferentes tipos de pista: asfalto regular, paralelepípedo e estrada de chão, caracterizando condições comuns nas cidades brasileiras. Para avaliar as vibrações transmitidas ao condutor, valores de aceleração foram registrados usando um acelerômetro tipo seat-pad montado no assento do motorista. Os resultados mostraram que o tipo de terreno que mais afeta a vibração de corpo inteiro no motorista é o paralelepípedo. Também foi possível detectar a ineficiência da poltrona do motorista quanto à absorção da vibração. Finalmente, observou-se que os motoristas não tiveram influência significativa nos resultados finais. / Bus drivers are daily exposed to whole-body vibrations (WBV) submitted to risks for develop health problems related to these conditions. Numerous studies focused to quantify and identify the risks that drivers are exposed have been developed in recent years. Many factors influence the transmission of vibration to the body. Road type may be an important factor in determining the WBV exposure which a bus driver receives. In urban areas, common types of routes include several road surfaces like: smooth highway, older rough freeway, pavement, bumpy, speed humps, and others. The purpose of this study is to determine whether different kinds of road surfaces, found in urban routes, cause different WBV responses, and determine the influence for each road type in daily exposure to WBV according the standard ISO 2631-1 (1997). Two different drivers drove the same urban bus over a route which included three road types: a rougher old freeway, a city street segment with pavement, and a road bumpy segment, characterizing the conditions of most Brazilian cities. To assess vibrations transmitted to the driver, vibration values were recorded using a seat pad accelerometer mounted on the driver’s seat. The results showed that the road type with the highest level of whole body vibration on the driver is the asphalt. It was also possible to detect the inefficiency of the driver's seat as the vibration absorption. Finally, it was observed that the drivers had no significant influence on the final results.

Motoristas de ônibus estão diariamente expostos a vibrações de corpo inteiro (VCI), o que os submetem a riscos de desenvolver problemas de saúde relacionados a essas condições. Numerosos estudos focados em quantificar e identificar os riscos a que os motoristas estão expostos foram desenvolvidos nos últimos anos. Porém, pesquisas mostram que muitos fatores influenciam na transmissão da vibração ao corpo humano. Estradas podem ser consideradas um fator importante na determinação da exposição à VCI que um motorista de ônibus recebe. Nas áreas urbanas, os tipos mais comuns de estradas encontradas são: asfalto bom, asfalto irregular, paralelepípedo, estrada de chão, estradas esburacadas, entre outros. O objetivo deste estudo é determinar se diferentes tipos de estradas, encontradas em vias urbanas, provocam diferentes respostas de VCI; e determinar a influência de cada tipo de estrada na exposição à VCI de acordo com a norma ISO 2631-1 (1997). Dois motoristas diferentes guiaram o mesmo ônibus urbano sobre diferentes tipos de pista: asfalto regular, paralelepípedo e estrada de chão, caracterizando condições comuns nas cidades brasileiras. Para avaliar as vibrações transmitidas ao condutor, valores de aceleração foram registrados usando um acelerômetro tipo seat-pad montado no assento do motorista. Os resultados mostraram que o tipo de terreno que mais afeta a vibração de corpo inteiro no motorista é o paralelepípedo. Também foi possível detectar a ineficiência da poltrona do motorista quanto à absorção da vibração. Finalmente, observou-se que os motoristas não tiveram influência significativa nos resultados finais. / Bus drivers are daily exposed to whole-body vibrations (WBV) submitted to risks for develop health problems related to these conditions. Numerous studies focused to quantify and identify the risks that drivers are exposed have been developed in recent years. Many factors influence the transmission of vibration to the body. Road type may be an important factor in determining the WBV exposure which a bus driver receives. In urban areas, common types of routes include several road surfaces like: smooth highway, older rough freeway, pavement, bumpy, speed humps, and others. The purpose of this study is to determine whether different kinds of road surfaces, found in urban routes, cause different WBV responses, and determine the influence for each road type in daily exposure to WBV according the standard ISO 2631-1 (1997). Two different drivers drove the same urban bus over a route which included three road types: a rougher old freeway, a city street segment with pavement, and a road bumpy segment, characterizing the conditions of most Brazilian cities. To assess vibrations transmitted to the driver, vibration values were recorded using a seat pad accelerometer mounted on the driver’s seat. The results showed that the road type with the highest level of whole body vibration on the driver is the asphalt. It was also possible to detect the inefficiency of the driver's seat as the vibration absorption. Finally, it was observed that the drivers had no significant influence on the final results.

Motoristas de ônibus estão diariamente expostos a vibrações de corpo inteiro (VCI), o que os submetem a riscos de desenvolver problemas de saúde relacionados a essas condições. Numerosos estudos focados em quantificar e identificar os riscos a que os motoristas estão expostos foram desenvolvidos nos últimos anos. Porém, pesquisas mostram que muitos fatores influenciam na transmissão da vibração ao corpo humano. Estradas podem ser consideradas um fator importante na determinação da exposição à VCI que um motorista de ônibus recebe. Nas áreas urbanas, os tipos mais comuns de estradas encontradas são: asfalto bom, asfalto irregular, paralelepípedo, estrada de chão, estradas esburacadas, entre outros. O objetivo deste estudo é determinar se diferentes tipos de estradas, encontradas em vias urbanas, provocam diferentes respostas de VCI; e determinar a influência de cada tipo de estrada na exposição à VCI de acordo com a norma ISO 2631-1 (1997). Dois motoristas diferentes guiaram o mesmo ônibus urbano sobre diferentes tipos de pista: asfalto regular, paralelepípedo e estrada de chão, caracterizando condições comuns nas cidades brasileiras. Para avaliar as vibrações transmitidas ao condutor, valores de aceleração foram registrados usando um acelerômetro tipo seat-pad montado no assento do motorista. Os resultados mostraram que o tipo de terreno que mais afeta a vibração de corpo inteiro no motorista é o paralelepípedo. Também foi possível detectar a ineficiência da poltrona do motorista quanto à absorção da vibração. Finalmente, observou-se que os motoristas não tiveram influência significativa nos resultados finais. / Bus drivers are daily exposed to whole-body vibrations (WBV) submitted to risks for develop health problems related to these conditions. Numerous studies focused to quantify and identify the risks that drivers are exposed have been developed in recent years. Many factors influence the transmission of vibration to the body. Road type may be an important factor in determining the WBV exposure which a bus driver receives. In urban areas, common types of routes include several road surfaces like: smooth highway, older rough freeway, pavement, bumpy, speed humps, and others. The purpose of this study is to determine whether different kinds of road surfaces, found in urban routes, cause different WBV responses, and determine the influence for each road type in daily exposure to WBV according the standard ISO 2631-1 (1997). Two different drivers drove the same urban bus over a route which included three road types: a rougher old freeway, a city street segment with pavement, and a road bumpy segment, characterizing the conditions of most Brazilian cities. To assess vibrations transmitted to the driver, vibration values were recorded using a seat pad accelerometer mounted on the driver’s seat. The results showed that the road type with the highest level of whole body vibration on the driver is the asphalt. It was also possible to detect the inefficiency of the driver's seat as the vibration absorption. Finally, it was observed that the drivers had no significant influence on the final results.

This study seeks to take a closer look at how to create a reliable and repeatable method for comparative measurement and analysis of comfort regarding vibrations in strollers.To achieve this goal the study has been divided in three questions that focuses on established standards and previous studies, a construction of a measurement method and finally a construction of a data analysis method. To answer these questions the study uses information gathered from a literature study, conducted experiments as well as an analysis of quantitative data via descriptive statistics and thematic analysis. Furthermore, during the development of the comparative method the authors has made use of various workshops to generate ideas and evaluate the best course of action. This has allowed for rapid iteration of the method that is presented in this report.To make a comparison with previous studies possible, ISO-2631:1, ISO-102361:1 and the Swedish Work Environment Authority’s regulations regarding whole body vibration are used as a foundation for the decisions made. The final method is presented in its entirety, both regardingmeasurement and data analysis. This study also displays an example of how both methods can be used to compare strollers.Additionally, the report applies the developed method on a selection of Thules’ and their competitors’ strollers. For the purpose of anonymity, the strollers’ brand and names has beenreplaced with code names and taken pictures has been replaced by illustrations.Finally, the results of the report is analyzed and discussed to compare the decisions taken throughout the process with each other as well as with the current standards, regulations and previous studies. Moreover, a conclusion in made that the presented methodology is a fair toolfor measurement of the passengers’ comfort with regard whole body vibrations in strollersduring activity. The resulting data is directly comparable on a case-by-case basis, but caution is advised if comparisons are to be made with the guidelines provided in presented standards or the regulations regarding whole body vibration, as these are not adapted for measurementsconducted with children.

To produce competitive vehicles, their comfort is one important issue to take into account during the development process. The aim of this Master Thesis is to develop an on-line comfort evaluation tool in order to improve research and education in the field of vehicle comfort at the division of Vehicle Dynamics at the Royal Institute of Technology. Based on ISO standards concerning comfort an on-line evaluation tool has been developed using DASYLab, which is a software that allows creation of acquisition, control, simulation and analysis tasks. The developed tool has been evaluated by performing measurements of a VOLVO V40 equipped with sensors. Different sorts of surfaces and driving conditions have been investigated, and from this investigation one can conclude that the comfort tool works properly.

High speed in waves, necessary in for instance rescue or military operations, often result in severe loading on both the craft and the crew. To maximize the performance of the high-speed craft (HSC) system that the craft and crew constitute, balance between these loads is essential. There should be no overload or underuse of crew, craft or equipment. For small high-speed craft systems, man is often the weakest link. The human exposure to vibration and shock results in injuries and other adverse health effects, which increase the risks for non-safe operations and performance degradation of the crew and craft system. To achieve a system in balance, the human acceleration exposure must be considered early in ship design. It must also be considered in duty planning and in design and selection of vibration mitigation systems. The thesis presents a simulation-based method for prediction and evaluation of the acceleration exposure of the crew on small HSC. A numerical seat model, validated with experimental full-scale data, is used to determine the crew's acceleration exposure. The input to the model is the boat acceleration expressed in the time domain (simulated or measured), the total mass of the seated human, and seat specific parameters such as mass, spring stiffness and damping coefficients and the seat's longitudinal position in the craft. The model generates seat response time series that are evaluated using available methods for evaluation of whole-body vibration (ISO 2631-1 \&amp; ISO 2631-5) and statistical methods for calculation of extreme values. The presented simulation scheme enables evaluation of human exposure to vibration and shock at an early stage in the design process. It can also be used as a tool in duty planning, requirements specification or for design of appropriate vibration mitigation systems. Further studies is proposed within three areas: investigation of the actual operational profiles of HSC, further development of seat models and investigation of the prevailing injuries and health problems among the crew of HSC. / <p>QC 20150126</p>

Passenger ride vibration comfort is a critical aspect to consider while developing any vehicle and there is a need to understand how the occupants would be affected when driving on different road profile roughness. Hence, road profile generation is critical as road profiles are used as inputs to simulation tools to investigate vehicle dynamic behaviour in depth. At the same time, the optimisation of the vehicle characteristics can be conducted on the various road profiles in order to identify a solution that can provide enhanced ride comfort and improve vehicle handling for all the investigated road profiles. The objective of this thesis is to study ride vibrational comfort and optimise the suspension system for theNational Electric Vehicle Sweden (NEVS) vehicle model for better ride comfort and road holding. Synthetic road profiles are generated by using stochastic processes according to International Organization for Standardization (ISO) 8608 standards. Further, simulations are conducted in MSC ADAMS Car software using the generated synthetic road profiles for a rigid body NEVS vehicle model to study the vertical accelerations. The analysis includes the investigations of the acceleration Power Spectral Density (PSD) and observations are made on the peaks that appear (at Front Seat Rail (FSR) which is the sprung mass of the vehicle and Wheel centre (WC) which is the un-sprung mass of the vehicle) for different road types and vehicle velocities. It is decided that the comfort objective will be used considering the weighted Root Mean Square (RMS) accelerations. Further, the suspension system of the vehicle model is optimised for three different road profiles (A, B, and C) based on the objectives of ride comfort and handling using a suitable vehicle model with the same characteristics as theNEVScar. A multi-objective optimisation technique is used and the optimised results are observed and discussed. Optimal objectives (based on a compromise between ride comfort and road holding) for the suspension system are determined for each investigated road profile. / Vibrationskomfort för passagerare är en kritisk aspekt att tänka på när man utvecklar ett fordon och det finns ett behov av att förstå hur passagerarna kan påverkas när de åker på olika vägprofiler. Därför är vägprofilgenerering avgörande eftersom vägprofiler används som input till simuleringsverktyg för att undersöka fordonets dynamiska beteende. Samtidigt kan optimeringen av fordonets egenskaper utföras på de olika vägprofilerna för att identifiera en lösning som kan ge ökad åkkomfort och förbättra fordonshanteringen för alla undersökta vägprofiler. Syftet med detta examensarbete är att studera körvibrationskomfort och optimera fjädringssystemet för NEVS fordonsmodellen för bättre åkkomfort och väghållning. Syntetiska vägprofiler genereras genom att använda stokastiska processer enligt ISO 8608 standarder. Dessutom utförs simuleringar i MSC ADAMS programvara med hjälp av de genererade syntetiska vägprofilerna för en stelkropps NEVS fordonsmodell för att studera de vertikala accelerationerna. Analysen inkluderar undersökningar av accelerations PSD och observationer görs av topparna som visas (vid FSR och WC) för olika vägtyper och fordonshastigheter. Det beslutas att komfortmålet kommer att utvärderas med hänsyn till endast de vägda RMS accelerationerna. Dessutom är fordonsmodellens hjul upphängningssystem optimerat för tre olika vägprofiler (A, B och C) baserat på målen för åkkomfort och väghållning med hjälp av en lämplig fordonsmodell med samma egenskaper som NEVS bilen. En multi-purpose optimeringsteknik används och de optimerade resultaten observeras och diskuteras. Optimala mål (baserat på en kompromiss mellan åkkomfort och väghållning) för fjädringssystemet bestäms för varje undersökt vägprofil.