Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Optimisation of tether orientation in head and neck restraint systems.
Thesis (MEng)--Stellenbosch University, 2021.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | en_ZA |
| Published: |
Stellenbosch : Stellenbosch University
2021
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613900522913792 |
|---|---|
| access_status_str | Open Access |
| author | Clarke, V. P. |
| author2 | De Jongh, C. U. |
| author_browse | Clarke, V. P. De Jongh, C. U. |
| author_facet | De Jongh, C. U. Clarke, V. P. |
| author_sort | Clarke, V. P. |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123867 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:29.841Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/123867 Optimisation of tether orientation in head and neck restraint systems. Clarke, V. P. De Jongh, C. U. Van der Merwe, J. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Head and neck restraint Tether orientation Biomechanics UCTD Racing cars Automobile racing drivers -- Safety Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The Head and Neck Restraint (HNR) is a critical component of safety equipment for racing car drivers. In the event of a collision, this device lessens the forces acting on the driver’s head and neck. The working of the HNR relies on a tether, attached between the driver’s helmet and a shoulder support, which prevents excessive forward flexion during sudden deceleration. There appears to be a lack of published information describing the tether’s optimal orientation for injury risk minimisation. This project aims to correct this by determining the optimal orientation of the HNR’s tether. To this end, solid body models of the human and Anthropomorphic Test Device (ATD) head and neck regions were developed and the effects of various tether orientations were tested on these models. For the ATD model, the aluminium components were represented as solid bodies, while the rubber components were modelled as non-linear springs. This model was validated against neck calibration data as specified by ATD manu- facturers. In the human head and neck model, vertebrae were modelled as solid bodies, ligaments and intervertebral (IV) discs as non-linear springs and muscles as Hill-type muscle models. The human model was validated against data from a study involving human volunteers subjected to simulated frontal collisions. Both models predicted responses that were similar to the data in literature. The most significant differences were with the Occipital Condyle (OC) forces and moments where it was decided that these measurements should be closely monitored go- ing forward. The HNR’s tethers were modelled as linear springs with certain adjustable pa- rameters, such as the angle at which the tethers act. These parameters could then be passed to an optimisation algorithm to determine the optimal tether set-up. Three sets of objective functions were tested, where these functions computed the maxima of the Ni j Neck Injury Criterion (NIC), the scaled OC moment and the scaled OC axial force, respectively. It was found that, of all the parameters included in the optimisation problem, the tether angle had the greatest impact on the effectiveness of the HNR. While the human model’s optimal angle is nearly nine degrees below the horizontal, an average difference of 13 degrees is measured between the optimal angles of the two models. This could indicate that an HNR designed using a real-world ATD may yield a design that is not as effective for human users. In addition to deter- mining the optimal angle, it was found that moving the position of the attach- ment point on the helmet 36 mm upwards may further reduce the risk of injury. Finally, the addition of a second tether to the HNR does not appear to improve results. AFRIKAANSE OPSOMMING: Die kop-en-nekvertragingstoestel is ’n sleutelkomponent van veiligheids- toerusting vir renjaers. In die geval van ’n botsing verminder hierdie toestel die uitwerking van kragte op die kop en nek van die renjaer. Die werking van die kop-en-nekvertragingstoestel maak staat op ’n weerstandband, geheg aan die valhelm en ’n skouerstut, wat oormatige vorentoe-fleksie tydens skielike vertra- ging verhoed. Dit blyk dat daar ’n tekort is aan gepubliseerde inligting wat die weerstandband se optimale oriëntasie vir die vermindering van beseringsrisiko beskryf. Hierdie projek beoog om dit reg te stel deur die optimale oriëntasie van die kop-en-nekvertragingstoestel se weerstandband te bepaal. Ten einde hierdie doel te bereik is soliedeliggaam modelle van die kop-en-nekareas van die mens sowel as van die antropomorfiese toetstoestel ontwikkel en is die uitwerking van verskeie weerstandband oriëntasies op beide getoets. Vir die antropomorfiese toetstoestel se kop-en-nekmodel verteenwoordig soliede liggame die aluminium komponente en nie-lineêre vere die rubber kom- ponente. Nek-kalibrasie data van antropomorfiese toetstoestel-vervaardigers is gebruik om die werking van hierdie model te bevestig. In die menslike kop- en-nekmodel is werwels gemodelleer as soliede liggame, ligamente en inter- vertebrale skywe as nie-lineêre vere en spiere as “Hill”-tipe spiermodelle. Die werking van die menslike model is bevestig deur dit te vergelyk met vrywilligers wat in ander studies onderworpe is aan gesimuleerde frontale botsings. Beide modelle het reaksies voorspel wat soortgelyk is aan data in die literatuur. Die mees noemenswaardige verskille is gevind in die oksipitale kondiel se kragte en buigmomente—hier is besluit dat die opnames daarvan voortaan noukerig gemonitor moet word. Die kop-en-nekvertragingstoestel se weerstandbande is gemodelleer as lineêre vere met sekere verstelbare veranderlikes, o.a. die hoek waarteen die weerstandbande inwerk. Hierdie veranderlikes kan vir ’n oprimeringsalgoritme gevoer word om die optimale opset van die weerstandband te bepaal. Drie stelle doelwit funksies is getoets en deur díe te bereken het elk een van die vol- gende opgelewer: die maksimum Ni j nekbeserings-kriterium, die maksimum geskaalde oksipitale kondiel se buigmoment en die maksimum geskaalde ok- sipitale kondiel se aksiale krag. Daar is bevind dat, uit al die veranderlikes betrokke in die optimasie pro- bleem, die weerstandbandhoek die grootste impak gehad het op die doel- treffendheid van die kop-en-nekvertragingstoestel. Die menslike model se op- timale hoek is byna nege grade onder die horisontaal. ’n Gemiddelde verskil van 13 grade is gemeet tussen die twee modelle se optimale hoeke. Dít kan aandui dat ’n kop-en-nekvertragingstoestel wat ontwerp is met die gebruik van ’n werk-ike antropomorfiese toetstoestel ’n ontwerp kan oplewer wat nie ewe doeltref- fend is vir menslike gebruik nie. Buiten die vasstelling van die optimale hoek, is ook gevind dat indien die aanhegtingspunt van die weerstandband 36×10−3 m opwaarts geskuif word, die beseringsrisiko verder verminder kan word. Laas- tens is gevind dat die byvoeging van ’n tweede weerstandband tot die kop-en- nekvertragingstoestel klaarblyklik nie beter resultate oplewer nie. Masters 2021-11-30T20:47:46Z 2021-12-22T14:26:01Z 2021-11-30T20:47:46Z 2021-12-22T14:26:01Z 2021-12 Thesis http://hdl.handle.net/10019.1/123867 en_ZA Stellenbosch University 117 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Head and neck restraint Tether orientation Biomechanics UCTD Racing cars Automobile racing drivers -- Safety Clarke, V. P. Optimisation of tether orientation in head and neck restraint systems. |
| title | Optimisation of tether orientation in head and neck restraint systems. |
| title_full | Optimisation of tether orientation in head and neck restraint systems. |
| title_fullStr | Optimisation of tether orientation in head and neck restraint systems. |
| title_full_unstemmed | Optimisation of tether orientation in head and neck restraint systems. |
| title_short | Optimisation of tether orientation in head and neck restraint systems. |
| title_sort | optimisation of tether orientation in head and neck restraint systems |
| topic | Head and neck restraint Tether orientation Biomechanics UCTD Racing cars Automobile racing drivers -- Safety |
| url | http://hdl.handle.net/10019.1/123867 |
| work_keys_str_mv | AT clarkevp optimisationoftetherorientationinheadandneckrestraintsystems |