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A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods
Thesis (MEng) -- Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867614138893598720 |
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| access_status_str | Open Access |
| author | Trafford, Nicholas John |
| author2 | Venter, M. P. |
| author_browse | Trafford, Nicholas John Venter, M. P. |
| author_facet | Venter, M. P. Trafford, Nicholas John |
| author_sort | Trafford, Nicholas John |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng) -- Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127075 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:47:17.083Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127075 A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods Trafford, Nicholas John Venter, M. P. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Girders -- Testing Structural analysis (Engineering) Air-supported structures -- Design and construction UCTD Thesis (MEng) -- Stellenbosch University, 2023. ENGLISH SUMMARY: A parametric study into the arrangement of reinforcing cables of a Tensairity beam girder was conducted. A 1500mm long, 140mm diameter beam was constructed with low-cost and freely available materials and fabrication methods. Three-point bending tests were performed to find cable arrangement parameters responsible for decreasing the central deflection of the beam. The reference test used in the study contained one pair of cables, with each cable forming a helical shape of one revolution around the bladder in a symmetrical orientation. Comparisons with the reference test were confirmed with two-tailed, pooled, statistical t-tests based on a 95% confidence interval. In comparison to the reference test, using one pair of cables with two or three revolutions decreased the stiffness of the beam by 49.7% and 55%, respectively. Adding a second pair of cables with either two or three revolutions statistically increased the stiffness of the beam by 8.5% in the worst case and by 18.6% in the best case scenario. The shortening of each pair of cables by 0%, 1%, 2% and 3%, respectively, was also investigated. The increase in stiffness was found for cables shortened by at least 1%. However, there was no added stiffness past a 1% decrease in length. The cable shortening affected the beam's shape more significantly than the stiffness. A non-linear Finite Element (FE) model of the Tensairity beam was also produced with linear-elastic material models derived from material testing of two components of the beam. The beam deflection calculated by the FE model, agreed within 5% of the experimental testing. The model concluded that a no-slip, no-roll assumption between the bladder and cables is viable for future simulation of Tensairity beams with shorted cables. Experimental testing also demonstrated viable use of a proportional method for maintaining air-pressure, which can be tested on full-scale models in future studies. AFRIKAANSE OPSOMMING: 'n Parametriese studie wat fokus op die rangskikking van versterkingskabels van 'n Tensairity steunbalk is uitgevoer. 'n 1500mm lang, 140mm deursnee balk is gebou met lae-koste en vrylik-beskikbare materiale en vervaardigingsmetodes. Driepuntbuigtoetse is uitgevoer om kabelrangskikkingsparameters te vind wat verantwoordelik is vir die vermindering van die sentrale defleksie van die balk. Die verwysingstoets wat in die studie gebruik is bevat een stel kabels, met elke kabel wat 'n heliese vorm van een omwenteling rondom die lugbal in 'n simmetriese orientasie. Vergelykings met die verwysingstoets is bevestig met 'n tweekantige, saamgevoegde, statistiese t-toetse gebaseer op 'n 95% vertrouensinterval. In vergelyking met die verwysingstoets het een stel kabels na twee of drie omwentelinge die styfheid van die balk verminder met onderskeidelik 49.7% en 55%. Deur 'n tweede stel kabels by te voeg met twee of drie omwentelinge het die styfheid van die balk statisties verhoog met 8.5% in die ergste geval en met 18.6% in die beste geval. Die verkorting van elke stel kabels met onderskeidelik 0%, 1%, 2% en 3% is ook ondersoek. Die toename in styfheid is gesien in kabels wat met ten minste 1% verkort is. Daar was egter geen ekstra styfheid verby 'n 1% afname in lengte nie. Die verkorting van die kabel het die vorm die balk aansienlik meer be invloed as die styfheid. 'n Nie-lineere Eindige Element (EE) model van die Tensairity balk is ook vervaardig met lineer-elastiese materiaalmodelle afkomstig van materiaaltoetsing van twee komponente van die balk. Die balkbuiging soos bereken met die EEmodel het binne 5% ooreengekom met die eksperimentele toetsing. Die model het tot die gevolgtrekking gekom dat 'n glyvaste, geen-rol aanname tussen die lugbal en die kabels lewensvatbaar is vir toekomstige simulasie van Tensairity balk met verkorte kabels. Eksperimentele toetsing het ook 'n lewensvatbare gebruik getoon van 'n proporsionele metode vir die handhawing van lugdruk, wat in toekomstige studies op volskaalse modelle getoets kan word. Masters 2023-03-02T12:25:11Z 2023-05-18T07:03:03Z 2023-03-02T12:25:11Z 2023-05-18T07:03:03Z 2023-03 Thesis http://hdl.handle.net/10019.1/127075 en_ZA Stellenbosch University xi, 89 pages : illustrations, includes annexures application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Girders -- Testing Structural analysis (Engineering) Air-supported structures -- Design and construction UCTD Trafford, Nicholas John A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title | A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title_full | A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title_fullStr | A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title_full_unstemmed | A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title_short | A parametric study of the cable positioning of Tensairity beam members using experimental and finite element methods |
| title_sort | parametric study of the cable positioning of tensairity beam members using experimental and finite element methods |
| topic | Girders -- Testing Structural analysis (Engineering) Air-supported structures -- Design and construction UCTD |
| url | http://hdl.handle.net/10019.1/127075 |
| work_keys_str_mv | AT traffordnicholasjohn aparametricstudyofthecablepositioningoftensairitybeammembersusingexperimentalandfiniteelementmethods AT traffordnicholasjohn parametricstudyofthecablepositioningoftensairitybeammembersusingexperimentalandfiniteelementmethods |