Low and high velocity impact evaluation of self-stiffening gel
This study analyses the dynamic mechanical properties and behaviour of pure shear-stiffening gel (SSG) and evaluates its potential for sports protective equipment (SPE). The SSG, polyborondimethylsiloxane (PBDMS), was tested at three different types of velocities ranges, (a) low; (b) medium; (c) hig...
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| Format: | Final Year Project (FYP) |
| Language: | English |
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Nanyang Technological University
2021
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| Online Access: | https://hdl.handle.net/10356/150206 |
| _version_ | 1811679335393787904 |
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| author | Tng, Jerrell |
| author2 | Leong Kah Fai |
| author_facet | Leong Kah Fai Tng, Jerrell |
| author_sort | Tng, Jerrell |
| collection | NTU |
| description | This study analyses the dynamic mechanical properties and behaviour of pure shear-stiffening gel (SSG) and evaluates its potential for sports protective equipment (SPE). The SSG, polyborondimethylsiloxane (PBDMS), was tested at three different types of velocities ranges, (a) low; (b) medium; (c) high. The different velocities correspond to the different situation the PBDMS is subjected to as well as the three different states of PBDMS. The lack of comfort and mobility of most SPE has led to higher sports injury rates, demanding the need for new materials for SPE. Even though SSG-based foam variants have been used in the SPE industry, the use of pure SSG has not been evaluated. Also, the thickness of SSG in relation to its impact absorption performance has not been clarified. The small amplitude oscillatory analysis (SAOS) was used to evaluate the low velocity properties of PBDMS. The impact drop weight test was to quantify how thickness affect various factors of PBDMS and to compare PBDMS with EVA. Split Hopkinson’s pressure bar (SHPB) test was used to test the PBDMS sample at high velocity. Results from the three test indicates the three different states of PBDMS: (a) viscous; (b) elastic; (c) glassy.Under the angular frequency of 11.1 rad/s, PBDMS exhibits liquid-like behaviour, indicating high comfort and mobility for low velocity activities. At impact energy of 15 J and above, the 11 mm PBDMS sample outperforms the 11 mm Ethyl vinyl acetate (EVA) sample in loading capacity and elastic recovery. Although, high velocity studies show that PBDMS behaves like a glassy solid and shatters at 4980/s, these velocities are highly unachievable under normal sporting circumstances. These results suggest that the desirable viscoelastic properties of PBDMS, compared to EVA, making it a superior material for SPE. |
| first_indexed | 2024-10-01T03:07:31Z |
| format | Final Year Project (FYP) |
| id | ntu-10356/150206 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:07:31Z |
| publishDate | 2021 |
| publisher | Nanyang Technological University |
| record_format | dspace |
| spelling | ntu-10356/1502062021-05-25T06:13:05Z Low and high velocity impact evaluation of self-stiffening gel Tng, Jerrell Leong Kah Fai School of Mechanical and Aerospace Engineering mkfleong@ntu.edu.sg Engineering::Materials::Material testing and characterization Engineering::Mechanical engineering This study analyses the dynamic mechanical properties and behaviour of pure shear-stiffening gel (SSG) and evaluates its potential for sports protective equipment (SPE). The SSG, polyborondimethylsiloxane (PBDMS), was tested at three different types of velocities ranges, (a) low; (b) medium; (c) high. The different velocities correspond to the different situation the PBDMS is subjected to as well as the three different states of PBDMS. The lack of comfort and mobility of most SPE has led to higher sports injury rates, demanding the need for new materials for SPE. Even though SSG-based foam variants have been used in the SPE industry, the use of pure SSG has not been evaluated. Also, the thickness of SSG in relation to its impact absorption performance has not been clarified. The small amplitude oscillatory analysis (SAOS) was used to evaluate the low velocity properties of PBDMS. The impact drop weight test was to quantify how thickness affect various factors of PBDMS and to compare PBDMS with EVA. Split Hopkinson’s pressure bar (SHPB) test was used to test the PBDMS sample at high velocity. Results from the three test indicates the three different states of PBDMS: (a) viscous; (b) elastic; (c) glassy.Under the angular frequency of 11.1 rad/s, PBDMS exhibits liquid-like behaviour, indicating high comfort and mobility for low velocity activities. At impact energy of 15 J and above, the 11 mm PBDMS sample outperforms the 11 mm Ethyl vinyl acetate (EVA) sample in loading capacity and elastic recovery. Although, high velocity studies show that PBDMS behaves like a glassy solid and shatters at 4980/s, these velocities are highly unachievable under normal sporting circumstances. These results suggest that the desirable viscoelastic properties of PBDMS, compared to EVA, making it a superior material for SPE. Bachelor of Engineering (Mechanical Engineering) 2021-05-25T06:13:05Z 2021-05-25T06:13:05Z 2021 Final Year Project (FYP) Tng, J. (2021). Low and high velocity impact evaluation of self-stiffening gel. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/150206 https://hdl.handle.net/10356/150206 en B011 application/pdf Nanyang Technological University |
| spellingShingle | Engineering::Materials::Material testing and characterization Engineering::Mechanical engineering Tng, Jerrell Low and high velocity impact evaluation of self-stiffening gel |
| title | Low and high velocity impact evaluation of self-stiffening gel |
| title_full | Low and high velocity impact evaluation of self-stiffening gel |
| title_fullStr | Low and high velocity impact evaluation of self-stiffening gel |
| title_full_unstemmed | Low and high velocity impact evaluation of self-stiffening gel |
| title_short | Low and high velocity impact evaluation of self-stiffening gel |
| title_sort | low and high velocity impact evaluation of self stiffening gel |
| topic | Engineering::Materials::Material testing and characterization Engineering::Mechanical engineering |
| url | https://hdl.handle.net/10356/150206 |
| work_keys_str_mv | AT tngjerrell lowandhighvelocityimpactevaluationofselfstiffeninggel |