<p>Scania has a policy to attain a high crashworthiness standard and their trucks have to conform to Swedish cab safety standards. The main objective of this thesis is to clarify which parameter variations, present during the second part of the Swedish cab crashworthiness test on a Scania R-series cab, that have significance on the intrusion response. An LS-DYNA FE-model of the test case is analysed where parameter variations are introduced through the use of the probabilistic analysis tool LS-OPT.</p><p>Example of analysed variations are the sheet thickness variation as well as the material variations such as stress-strain curve of the structural components, but also variations in the test setup such as the pendulum velocity and angle of approach on impact are taken into account. The effect of including the component forming in the analysis is investigated, where the variations on the material parameters are implemented prior to the forming. An additional objective is to analyse the influence of simulation and model dependent variations and weigh their respective effect on intrusion with the above stated physical variations.</p><p>A submodel is created due to the necessity to speed up the simulations since the numerous parameter variations yield a large number of different designs, resulting in multiple analyses.</p><p>Important structural component sensitivities are taken from the results and should be used as a pointer where to focus the attention when trying to increase the robustness of the cab. Also, the results show that the placement of the pendulum in the y direction (sideways seen from the driver perspective) is the most significant physical parameter variation during the Swedish pendulum test. It is concluded that to be able to achieve a fair comparison of the structural performance from repeated crash testing, this pendulum variation must be kept to a minimum. </p><p>Simulation and model dependent parameters in general showed to have large effects on the intrusion. It is concluded that further investigations on individual simulation or model dependent parameters should be performed to establish which description to use. </p><p>Mapping material effects from the forming simulation into the crash model gave a slight stiffer response compared to the mean pre-stretch approximations currently used by Scania. This is still however a significant result considering that Scanias approximations also included bake hardening effects from the painting process. </p>

Scania has a policy to attain a high crashworthiness standard and their trucks have to conform to Swedish cab safety standards. The main objective of this thesis is to clarify which parameter variations, present during the second part of the Swedish cab crashworthiness test on a Scania R-series cab, that have significance on the intrusion response. An LS-DYNA FE-model of the test case is analysed where parameter variations are introduced through the use of the probabilistic analysis tool LS-OPT. Example of analysed variations are the sheet thickness variation as well as the material variations such as stress-strain curve of the structural components, but also variations in the test setup such as the pendulum velocity and angle of approach on impact are taken into account. The effect of including the component forming in the analysis is investigated, where the variations on the material parameters are implemented prior to the forming. An additional objective is to analyse the influence of simulation and model dependent variations and weigh their respective effect on intrusion with the above stated physical variations. A submodel is created due to the necessity to speed up the simulations since the numerous parameter variations yield a large number of different designs, resulting in multiple analyses. Important structural component sensitivities are taken from the results and should be used as a pointer where to focus the attention when trying to increase the robustness of the cab. Also, the results show that the placement of the pendulum in the y direction (sideways seen from the driver perspective) is the most significant physical parameter variation during the Swedish pendulum test. It is concluded that to be able to achieve a fair comparison of the structural performance from repeated crash testing, this pendulum variation must be kept to a minimum. Simulation and model dependent parameters in general showed to have large effects on the intrusion. It is concluded that further investigations on individual simulation or model dependent parameters should be performed to establish which description to use. Mapping material effects from the forming simulation into the crash model gave a slight stiffer response compared to the mean pre-stretch approximations currently used by Scania. This is still however a significant result considering that Scanias approximations also included bake hardening effects from the painting process.

Syfte – Studien syftar till att kartlägga hur kundorderpunktens position förhåller sig till företags val av säkerhetskapacitetsbuffertar för att hantera stokastiska variationer i kapacitetsbehov. Därmed är studiens frågeställningar: Vilka är de huvudsakliga säkerhetskapacitetsbuffertarna som används för att hantera stokastiska variationer i kapacitetsbehov? Hur förhåller sig kundorderpunktens position till val av säkerhetskapacitetsbuffertar för att hantera stokastiska variationer i kapacitetsbehov? Metod – För att besvara studiens frågeställningar har en fallstudie genomförts och inkluderar en litteraturstudie, intervjuer och dokumentstudier. Intervjuer genomfördes med sju respondenter från sex företag och empirin som framkom från intervjuerna och dokumentstudier analyserades tillsammans med teori från litteraturstudien för att få fram studiens resultat. Resultat – Studien har identifierat tio tillvägagångssätt för att hantera stokastiska variationer, varav två som inte tidigare nämnts av studiens teoretiska ramverk. De tio tillvägagångssätten har därefter kategoriserats in i sex säkerhetskapacitetsbuffertar baserat på likheter. Efter identifiering av kundorderpunktens position har möjliga kopplingar mellan kundorderpunktens position och val av säkerhetskapacitetsbuffert analyserats för att undersöka eventuella samband. Tre tendenser till kopplingar har identifierats men vidare studier krävs för att säkerställa kopplingarna. Implikationer – Området kring hantering av variationer i kapacitetsbehov med en uppdelning i en kapacitetsbuffert och en säkerhetskapacitetsbuffert är relativt outforskat. Att undersöka eventuella kopplingar mellan val av säkerhetskapacitetsbuffertar och kundorderpunktens position kan fylla ett kunskapsgap och kan teoretiskt bidra till vidare studier inom området säkerhetskapacitetsbuffertar. Genom att lära av andras erfarenheter ges en ökad förståelse vilket kan hjälpa företag att fatta mer välgrundade beslut vilket kan leda till förbättrad prestation, vilket är studiens praktiska bidrag. Begränsningar – Studiens begränsning ligger i att endast sju respondenter från sex företag ingick i studien, där endast en intervju gjordes med respektive respondent. Antalet använda tillvägagångssätt och deras kopplingar till kundorderpunktens position hade kunnat stärkas ifall ett större antal respondenter från olika typer av företag deltagit i studien. Därigenom hade kopplingarnas generaliserbarhet kunnat stärkas. Dessutom hade troligtvis fler tillvägagångssätt identifierats ifall en större bredd studerats. I studien har den totala kapaciteten hanteras som två separata delar för hantering av förväntade och oväntade behov. Infallsvinkeln är relativt ny och är inte etablerad vilket kan försvåra och begränsa förutsättningen för verksamheter att applicera resultatet. / Purpose – The study aims to map how the position of the order penetration point is related to companies’ choice to handle stochastic variations in capacity requirements through the use of safety capacity buffers. Hence, the research questions are: 1. Which are the main safety capacity buffers used to handle stochastic variations in capacity requirements? 2. How is the position of the order penetration point related to the choice of safety capacity buffers to handle stochastic variations? Method – A case study has been conducted in order to answer the research questions and thus includes a literature study, interviews and document studies. The interviews were conducted with seven respondents from six companies and the empirical data that emerged from the interviews and document studies were analysed together with theory from the literature study to reach the result of the study. Findings – The study has identified ten approaches to handle stochastic variations, two of which was not previously mentioned in the theoretical framework. The ten approaches have then been categorized into six safety capacity buffers based on similarities. After identifying the position of the order penetration point possible connections between the position of the order penetration point and choice of safety capacity buffers have been analysed to explore possible relationships. Three tendencies to connections have been identified but further studies are required to ensure the connections. Implications – The research area of handling variations in capacity requirements with a division in one capacity buffer and one safety capacity buffer is relatively unexplored. Exploring possible connections between the choice of safety capacity buffers and the position of the order penetration point could fill a gap of knowledge and theoretically contribute to further research within the area of safety capacity buffers. Learning of others’ experiences gives an increased understanding which can help companies to make more informed decisions that can lead to better performance, which is the practical contribution of the study. Limitations – The studies limitations lies in that only seven respondents from six companies were included in the study, were only one interview was conducted with each respondent. The number of used approaches and their connections to the order penetrations point could have been strengthened in case an increased number of respondents from different kind of companies had participated in the study. Thereby the connections’ generalizability could have been strengthened. Additionally more approaches probably would have been identified in case a greater width had been studied. In the study the total capacity have been handled as two separated parts to handle expected and unexpected requirements. The approach is relatively new and not established which can complicate and limit the ability for companies to apply the results.