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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Characteristics of nearside car crashes : an integrated approach to side impact safety

Sunnevång, Cecilia January 2016 (has links)
Introduction: Approximately 1.25 million people globally are killed in traffic accidents yearly. To achieve the UN Global Goal of a 50% reduction of fatal and serious injuries in 2020 a safer infrastructure, as well as new safety technologies, will be needed. Side crashes represent 20% of all serious and 25 % of fatal injuries. The overall aim of this thesis is to provide guidelines for improved side impact protection. First, by characterizing nearside crashes and injury outcome, including injuries from the farside occupant, for non-senior and senior front seat occupants. Second, to determine whether the WorldSID dummy provides opportunities for improved in-crash occupant protection. And third, by relating in-crash occupant protection to pre-crash countermeasures, to explore a holistic approach for side crashes using the integrated safety chain from safe driving to crash. Methods: NASS/CDS data for both older and modern vehicles was used to provide exposure, incidence, and risk for fatal injury as well as detailed injury distribution and crash characteristics. The WorldSID dummy was compared to Post Mortem Human Subjects (PMHS) in impactor tests at high and low severities to demonstrate the possibilities of this tool. Crash tests were performed to evaluate WorldSID crash test dummy assessments of injuries found in the NASS/CDS data. The integrated safety chain was used to demonstrate how to evaluate occupant protection in side crashes from a larger perspective, involving infrastructure and Automated Emergency Braking. Result: Most side crashes occur at intersections. The head, thorax, and pelvis are the most frequently injured body regions, and seniors have a higher risk for rib fractures compared to non-seniors. The WorldSID dummy response was similar to the PMHS response at the higher impact speed, but not at the lower. In conjunction with improved airbags infrastructural change, and the use of Automated Emergency Braking, can effectively reduce the number of fatalities and injured occupants in side impacts. Conclusion: Future focus for side impact protection should be on intersection crashes, improved occupant protection for senior occupants, and protection for and from the farside occupant, reducing injury risk to the head, thorax, and pelvis. The WorldSID dummy has the ability to reproduce humanlike responses in lateral and oblique impacts. However, at a low crash severity, chest deflection could be underestimated, which must be taken into consideration when evaluating, for example, pre-crash inflated side airbags. Analyzing nearside crashes using the integrated safety chain shows that speed management by means of roundabouts is an efficient countermeasure reducing the number of injurious crashes, as well as reducing variations in crash severity. In combination with an Automated Emergency Braking a large part of side crashes could be avoided or crash severity mitigated. Rather than developing structures and airbags for high-speed crashes, it is important to consider alternative countermeasures. Hence the need for an integrated approach to side impacts.
2

Improved side impact car safety : New IIHS side crash regulation, effect on product design

Bäckman, Andreas January 2022 (has links)
23% of passenger vehicle occupant deaths in 2019 was side-impact collisions and is a ongoing problem that continues to take people’s lives (IIHS, 2021a). IIHS (Insurance Institute for Highway Safety) is an organization based in USA, which performs vehicle crash tests with the goal of making cars safer and reducing deaths and injuries. In 2023, a new, tougher side crash test will be introduced by IIHS in the USA to tackle those crashes and save lives. The goal for IIHS with their vehicle tests is to urge the car manufacturers to make safer vehicles. Manufacturers in the automotive industry knows that the customers are using the ratings as a guide before buying a vehicle, which forces them to adapt the vehicles to pass the tests and have a good rating. In early crash tests with the updated side crash test, a lot of vehicles from a selection of different manufacturers struggled to pass the test requirements and it seems like the new test requires change of component strength and design.  This is a master thesis project in Industrial Design Engineering with the focus on Product Design, at Luleå University of Technology (LTU), and has been performed on behalf of Gestamp HardTech at their R&D department in Luleå, Sweden. The early parts project focused on finding which car components has the largest influence of the crash result, where the components might need to be reinforced or having less strength.  To help simulating the side crash, full vehicle side-impact crash simulations were used in this project with a virtual reference FEM car made by Gestamp, GLAB G3 EV. This project has been using the CDIO-design process, which stands for Conceive, Design, Implement and Operate.  In the first phase, Conceive, simulations were made and the current IIHS side crash test was compared with the new IIHS test. The left-side side-impact beams was chosen as the components to trying to improve in the project. Creative methods in the Design-phase were generated ideas, which was 3D CAD modeled in CATIA V5 and tested with three-point bending simulations in LS-DYNA.  The three-point bending simulations were analyzed and the best performing designs were chosen, to later be simulated with full vehicle side-impact crash simulations in the Implement-phase. The results from these simulations were used to develop ten different concepts of combinations of left-front and left-rear side-impact beams and ten final full vehicle simulations were conducted and analyzed on factors such as door intrusion, component weight and more. From these concepts, the two final concepts were selected with the use of the Pugh Decision Matrix, and these two concepts had the highest rating score from this matrix. These two concepts, Final Concept and Alternative Concept, are the final results of the project. Each concept has a combination of a left-front side-impact beam and a left-rear side-impact beam. The two final concepts are reducing the side crash intrusion on the side-impact beams compared to the reference simulations conducted with the new IIHS side crash test. The Final Concept were the best concept in the results from the matrix and is reducing the total side crash intrusion on the left-side of the car by 161 mm compared to the reference simulations The reason why an Alternative Concept to the Final Concept was selected was because it has very different design and thickness compared to the Final Concept, and even though it only has 94 mm total side crash intrusion  reduction on the left-side of the car compared to the reference simulation, it was looked on a potential alternative to the Final Concept with further work and development applied to it. / 23% av dödsfallen i passagerarfordon under 2019 var sidokrockar och är ett pågående problem som fortsätter att ta människors liv (IIHS, 2021a). IIHS (Insurance Institute for Highway Safety) är en organisation som är baserad i USA som utför fordonskrocktester med målet att göra bilar säkrare och minska dödsfall och skador. 2023 kommer ett nytt, tuffare sidokrocktest att introduceras av IIHS i USA för att tackla dessa krascher med målet att rädda fler liv. Målet för IIHS med sina fordonstester är att uppmana biltillverkarna att göra säkrare fordon. Tillverkare inom fordonsindustrin vet att kunderna använder betygen som vägledning innan de köper ett fordon, vilket tvingar dem att anpassa bilarna för att klara testerna och få ett bra testbetyg. I tidiga krocktester med det uppdaterade IIHS sidokrocktestet hade många bilar från ett flertal biltillverkare för att klara testkraven och det verkar som om det nya testet kräver förändring av styrka och design i bilens komponenter. Detta är ett examensarbete i Civilingenjör Teknisk Design med inriktning på produkt design vid Luleå Tekniska Universitet (LTU), och har utförts på uppdrag av Gestamp HardTech vid deras FoU-avdelning i Luleå, Sverige. Början av projektet fokuserade på att hitta vilka bilkomponenter som har störst inverkan på krockresultatet, ta reda på var komponenterna kan behöva förstärkas eller ha mindre styrka. För att hjälpa till att simulera sidokrocken användes helbilssidokrocksimuleringar i detta projekt med hjälp av en virtuell FEM-bil tillverkad av Gestamp, GLAB G3 EV. Detta projekt har använt CDIO-designprocessen, som står för Conceive, Design, Implement och Operate. I den första fasen, Conceive, gjordes simuleringar och det nuvarande IIHS sidokrocktestet jämfördes med det nya IIHS testet. De två sidokrock-skydden på vänstra sidan av bilen valdes som komponenter att försöka förbättra i projektet. Kreativa metoder i Design-fasen genererade idéer, som 3D CAD modellerades i CATIA V5 och testades med trepunktsböjnings-simuleringar i LS-DYNA. Trepunktsböjningssimuleringarna analyserades och de bästa presterande designerna valdes ut, för att senare simuleras med helbilssidokrock-simuleringar i Implement-fasen. Resultaten från dessa simuleringar användes för att utveckla tio olika koncept av kombinationer av sidokrockskydd till vänster fram och vänster bak av bilen och tio slutliga helbilssidokrock-simuleringarna genomfördes och analyserades på faktorer som intryckningen i dörrarna, komponenternas vikt med mera. Från dessa koncept valdes de två slutliga koncepten ut med hjälp av Pughs beslutsmatris, och dessa två koncept hade det högsta betyget från denna matris. Dessa två koncept, Final Concept och Alternative Concept, är projektets slutresultat. Varje koncept har en kombination av ett sidokrockskydd på vänster-fram och ett sidokrockskydd på vänster-bak. De två slutgiltiga koncepten minskar dörrintrånget på sidokrockskydden jämfört med referenssimuleringarna som genomfördes med det nya IIHS sidokrock-testet. Final Concept var det bästa konceptet i resultaten från matrisen och minskar det totala sidokrockintrånget på bilens vänstra sida med 161 mm jämfört med referenssimuleringarna. Anledningen till att ett alternativt koncept till det slutgiltiga konceptet valdes var eftersom den har väldigt olika design och tjocklek jämfört med det slutliga konceptet, och även om den bara har 94 mm total reduktion av sidokrockintrång på vänster sida av bilen jämfört med referenssimuleringen, såg man detta koncept som ett potentiellt alternativ till Final Concept med fortsatt arbete och utveckling tillämpat på detta koncept.

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