Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings
Natural gut harp strings are made from twisted bundles of gut strips, which are dried, ground, and varnished. The effects of varying the twist angle and surface finishing on the mechanical properties of gut harp strings have been explored. Strings were tested over a range of twist angles from 23.5&l...
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| Language: | English |
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MDPI AG
2023-08-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/16/15/5444 |
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| author | Nicolas Lynch-Aird Jim Woodhouse |
| author_facet | Nicolas Lynch-Aird Jim Woodhouse |
| author_sort | Nicolas Lynch-Aird |
| collection | DOAJ |
| description | Natural gut harp strings are made from twisted bundles of gut strips, which are dried, ground, and varnished. The effects of varying the twist angle and surface finishing on the mechanical properties of gut harp strings have been explored. Strings were tested over a range of twist angles from 23.5<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> to 58.3<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula>, and with all four combinations of ground or unground and varnished or unvarnished surface finishing. The principal effects of varying the degree of twisting were that the breaking strength and tensile Young’s modulus both fell as the twist angle was increased. String makers must therefore make a compromise between sound quality and string strength and durability. Leaving the string unvarnished dramatically increased the sensitivity to changes in humidity, which, in turn, affected the thermal tuning sensitivity and creep behaviour. Grinding the string surface prior to varnishing had no significant effect on the behaviour, but did make some difference to the thermal tuning sensitivity if the string was left unvarnished. Increasing the humidity frequently triggered episodes of additional string creep. There appeared to be a threshold effect, with the additional creep triggered when the string linear density exceeded its previous maximum. When the string was not creeping, there appeared to be a strong coupling mechanism between changes in the linear density and complementary changes in the string tension, such that there was almost no net effect on the string frequency. This behaviour was independent of the twist angle and the surface finishing, suggesting that whatever the coupling mechanism was, it was not dependent on the twisted structure of the string. |
| first_indexed | 2024-03-11T00:22:52Z |
| format | Article |
| id | doaj.art-d3c5747d048f4650a6e4ee3627fd1072 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T00:22:52Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-d3c5747d048f4650a6e4ee3627fd10722023-11-18T23:13:23ZengMDPI AGMaterials1996-19442023-08-011615544410.3390/ma16155444Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp StringsNicolas Lynch-Aird0Jim Woodhouse1The Old Forge, Burnt House Lane, Battisford, Suffolk IP14 2ND, UKDepartment of Engineering, University of Cambridge, Trumpington St, Cambridge CB2 1PZ, UKNatural gut harp strings are made from twisted bundles of gut strips, which are dried, ground, and varnished. The effects of varying the twist angle and surface finishing on the mechanical properties of gut harp strings have been explored. Strings were tested over a range of twist angles from 23.5<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> to 58.3<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula>, and with all four combinations of ground or unground and varnished or unvarnished surface finishing. The principal effects of varying the degree of twisting were that the breaking strength and tensile Young’s modulus both fell as the twist angle was increased. String makers must therefore make a compromise between sound quality and string strength and durability. Leaving the string unvarnished dramatically increased the sensitivity to changes in humidity, which, in turn, affected the thermal tuning sensitivity and creep behaviour. Grinding the string surface prior to varnishing had no significant effect on the behaviour, but did make some difference to the thermal tuning sensitivity if the string was left unvarnished. Increasing the humidity frequently triggered episodes of additional string creep. There appeared to be a threshold effect, with the additional creep triggered when the string linear density exceeded its previous maximum. When the string was not creeping, there appeared to be a strong coupling mechanism between changes in the linear density and complementary changes in the string tension, such that there was almost no net effect on the string frequency. This behaviour was independent of the twist angle and the surface finishing, suggesting that whatever the coupling mechanism was, it was not dependent on the twisted structure of the string.https://www.mdpi.com/1996-1944/16/15/5444gutstringharptwist ratiotwist anglesurface finish |
| spellingShingle | Nicolas Lynch-Aird Jim Woodhouse Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings Materials gut string harp twist ratio twist angle surface finish |
| title | Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings |
| title_full | Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings |
| title_fullStr | Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings |
| title_full_unstemmed | Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings |
| title_short | Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings |
| title_sort | effects of twisting and surface finish on the mechanical properties of natural gut harp strings |
| topic | gut string harp twist ratio twist angle surface finish |
| url | https://www.mdpi.com/1996-1944/16/15/5444 |
| work_keys_str_mv | AT nicolaslynchaird effectsoftwistingandsurfacefinishonthemechanicalpropertiesofnaturalgutharpstrings AT jimwoodhouse effectsoftwistingandsurfacefinishonthemechanicalpropertiesofnaturalgutharpstrings |