Slamming pressure on planing trimarans due to symmetric and asymmetric loads
Also available in printed version
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| Format: | Doctoral thesis |
| Language: | English |
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Universiti Teknologi Malaysia
2025
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| Online Access: | https://utmik.utm.my/handle/123456789/43094 |
| Abstract | Abstract here |
| _version_ | 1854934109245145088 |
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| author | Mooud Nikfarjam |
| author2 | Omar Yaakob, supervisor |
| author_facet | Omar Yaakob, supervisor Mooud Nikfarjam |
| author_sort | Mooud Nikfarjam |
| description | Also available in printed version |
| format | Doctoral thesis |
| id | utm-123456789-43094 |
| institution | Universiti Teknologi Malaysia |
| language | English |
| publishDate | 2025 |
| publisher | Universiti Teknologi Malaysia |
| record_format | dspace |
| record_pdf | Abstract |
| spelling | utm-123456789-430942025-08-20T23:58:22Z Slamming pressure on planing trimarans due to symmetric and asymmetric loads Mooud Nikfarjam Omar Yaakob, supervisor Mechanical engineering Also available in printed version Trimarans are high-performance speed boats which have significant advantages compared to the other marine vehicles. Trimarans have small wave-making resistance, smooth motion and excellent seakeeping, particularly in rough seas. The structural design of these vessels depends mostly on the estimation of impact loads which cannot be predicted accurately using the rules of classification societies for conventional high-speed crafts. In this thesis, the hydrodynamic impact pressures on planing trimarans were numerically and experimentally investigated. Two groups of models of trimaran and wedge sections were studied with different deadrise angles (15�-30�), weights (20-30 kg) and drop heights (50-100 cm) during symmetric and asymmetric water-entry. A numerical model for simulation of two-dimensional (2D) rigid models was developed using the Computational Fluid Dynamics (CFD) method with ANSYS-CFX to solve the fluid flow and evaluate the peak pressure, impulse and other related parameters. It was found that the effects of drop height and weight are not as significant as the effect of deadrise angles. In addition, although the amount of impact pressures for trimaran sections are slightly higher compared to the monohulls, 65% less impulse was experienced which could be attributed to the effect of side hulls and air cushion in tunnels and can be considered as an advantage of these hull forms. For validation purpose, model drop tests were carried out in water tank of Sharif University of Technology. The results show a good correlation between numerical and experimental data with 6% difference. The results were used to develop two mathematical models for the prediction of slamming pressures on monohulls and trimarans using Design of Experiment method. A new non-dimensional factor, named as factor of increase (FoI) was presented to show how the slamming pressures change by the geometry of the boat. In addition, a software (SPDC) based on MATLAB code was developed and the accuracy of outputs was evaluated by comparing with the rules of ship classification societies. It was shown that SPDC estimated the slamming pressures with 8% over prediction compared to the measurements. In addition, it was found that the outputs of SPDC can be used as an accurate guideline for the estimation of design loads. It was able to reduce the risk of over prediction of these loads for structural analysis while the weight of the structure can be lighter by about 30%. Therefore, the proposed method can be used by designers in the early stages of design instead of using empirical equations provided by the ship classification rules. On the other hand, the new model will improve the construction procedures, project time and cost because the structure can be built by lighter elements. fahmimoksen UTM 306 p. Thesis (Doktor Falsafah (Kejuruteraan Mekanikal)) - Universiti Teknologi Malaysia, 2019 2025-03-11T05:27:08Z 2025-03-11T05:27:08Z 2019 Doctoral thesis https://utmik.utm.my/handle/123456789/43094 vital:145000 valet-20220106-150927 ENG Closed Access UTM Complete Unpublished Completion application/pdf Universiti Teknologi Malaysia |
| spellingShingle | Mechanical engineering Mooud Nikfarjam Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| thesis_level |
PhD
|
| title | Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| title_full | Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| title_fullStr | Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| title_full_unstemmed | Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| title_short | Slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| title_sort | slamming pressure on planing trimarans due to symmetric and asymmetric loads |
| topic | Mechanical engineering |
| url | https://utmik.utm.my/handle/123456789/43094 |
| work_keys_str_mv | AT mooudnikfarjam slammingpressureonplaningtrimaransduetosymmetricandasymmetricloads |