Ship structural-integrity-of-aluminium, O.O. Sulaiman
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This document summarizes a study on the structural integrity of aluminum stiffener panels in ship structures. Three types of aluminum stiffener panels - flat, L-shaped, and T-shaped - were tested under bending and compressive loads. The results showed that panels in areas unaffected by welding heat had greater stability. T-shaped panels exhibited the highest ultimate load capacity, while flat panels showed the lowest deflection levels under bending. The study provides data on panel dimensions and material properties to determine the panel with the best strength for ship structural systems.
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Ship structural-integrity-of-aluminium, O.O. Sulaiman
- 1. Global Journal of Researches in Engineering Automotive Engineering Volume 12 Issue 2 Version 1.0 Year 2012 Type: Double Blind Peer Reviewed International Research Journal Publisher: Global Journals Inc. (USA) Online ISSN: 2249-4596 & Print ISSN: 0975-5861 Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction By O. O. Sulaiman, A.S.A.Kader, W.B.Wan Nick & A.H. Saharuddin University Malaysia Terengganu Abstract - The aluminium stiffener panels in ship structure are paramount to ensure safety and to guarantee the structural strength and integrity of the ship. The aluminium stiffener panel is very important to ship building, especially when the ship faces collision or unstabilized structure; the aluminium stiffener panel tends to increase bending moment, vertical shear force and stresses. This study investigate the strength of the aluminium stiffener panel at the amidship bulkhead with different shapes and typesin order to determine the strength of the aluminium stiffener from its features. AA 5083-H116 aluminium stiffener panel used has been approved by the recognized organization for shipbuilding. The aluminium stiffener panel has been tested using bending moment test and compressive load to obtain the highest endurance. Three types of aluminium stiffener panels, which are a flat shaped, L-shaped and T-shaped panel, are used in order to obtain the best panel ability for a better ship structural system. The aluminium stiffener panel is tested at the area where it is different to determine area where they are affected by extreme heat due to the welding results and fabrication. The result has showed that the aluminium stiffener panel in shipbuilding process effect in an area without extreme heat is more stable. Keywords : Ultimate strength, heat affected zone, collision damage, aluminium stiffener panel, bulkhead, amidships. GJRE-B Classification: FOR Code: 091207 Ship StructuralIntegrityofAluminiumStiffenerPanelforConsequenceReduction Strictly as per the compliance and regulations of: © 2012. O. O. Sulaiman, A.S.A.Kader, W.B.Wan Nick & A.H. Saharuddin. This is a research/review paper, distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License http://creativecommons.org/licenses/by- nc/3.0/), permitting all non commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
- 2. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction α σ ρ Ѡ O. O. Sulaiman , A.S.A.Kader , W.B.Wan Nick & A.H. Saharuddin Abstract - The aluminium stiffener panels in ship structure are geometrical imperfection, the width of the welding heat- paramount to ensure safety and to guarantee the structural affected zone (HAZ) and welding residual stresses are strength and integrity of the ship. The aluminium stiffener also examined. Year 2012 panel is very important to ship building, especially when the The study involved of ship structure ship faces collision or unstabilized structure; the aluminium construction and testing of different part of aluminium stiffener panel tends to increase bending moment, vertical shear force and stresses. This study investigate the strength of stiffener panel to investigate be more strength because the aluminium stiffener panel at the amidship bulkhead with they can cause support load weight on the ship such as different shapes and typesin order to determine the strength of machinery, fuel, oil and other equipment. Aluminium 11 the aluminium stiffener from its features. AA 5083-H116 stiffener should be more strengthen for support the ship aluminium stiffener panel used has been approved by the body, Therefore, it is important to find ship structure in recognized organization for shipbuilding. The aluminium Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I respect to fatigue todetermine structural integrity. stiffener panel has been tested using bending moment test and compressive load to obtain the highest endurance. Three b) Inherent Problem Associated with Ship Structure types of aluminium stiffener panels, which are a flat shaped, L- integrity shaped and T-shaped panel, are used in order to obtain the i. The variation in the buoyant forces increased the best panel ability for a better ship structural system. The bending moment, vertical shear force, , stresses aluminium stiffener panel is tested at the area where it is different to determine area where they are affected by extreme and amidships the buoyancy forces design in heat due to the welding results and fabrication. The result has such situation will tend to ‘hog’ the vessel, if the showed that the aluminium stiffener panel in shipbuilding trough is amidships the buoyancy forces will tend process effect in an area without extreme heat is more stable. to ‘sag’ the ship. Keywords : Ultimate strength, heat affected zone, ii. The stiffness against bending tend to increased collision damage, aluminium stiffener panel, bulkhead, by a hollow section with space between the amidships. stiffeners which is reduced by the twin-wall section shape compared to the single-wall I. Introduction stiffeners such as T-shaped or L-shaped a) Background stipulated by Ye N. and Moan T. (2007). T he stiffener panel on ship structure is one of the iii. Fatigue becomes the governing criteria in the support element from basic of building ship design of the mid-ship stiffener/web frame structure such as type flat bar, T bar and L bar connections at the top and bottom has studied by used in shipbuilding construction, they are used Ye N. (2007). commonly in the bulkhead and amidships. Study on The study asses ship structurereliability strength ship strength and integrity determined from life cycle of of aluminium stiffener panel from outside pressure and ship and return of investment leads to ship own or consequential damages. The study investigated the spending more money on maintenance. Stiffened plates aluminium stiffener strength by shape and type of in ships revealed that other structures may be exposed stiffener at bulkheads and amidships and determined to complex stress patterns due to simultaneously acting reliable effect of aluminium stiffener strength from their in-plane biaxial and shear stresses in design of such behavior. elements, buckling and ultimate strength are important issues researched by Brubak, L. and Hellesland J. II. Methodology (2008). Stiffened plates are required to resist extreme loading conditions, for example in term of axial The study process involves the following stages: compressive loads or lateral pressures studied by a) Theoretical Modeling Khedmati M.R., and Ghavami K. (2009). The principal The theory of stress and strain is compared with variables studied are the plate thickness, boundary the value of lab test for validation purpose to deduce conditions and the stiffener geometries beside the and recommendation as required. Compressive stress acts to reduce the length of the material (compression member) in the axis of the applied load is modelled. Author α σ ρ Ѡ : Maritime Technology Department, University Malaysia Terengganu. E-mails : [email protected], [email protected] © 2012 Global Journals Inc. (US)
- 3. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction b) Field Work at Shipyard weakness. The Hardness test required for welding The plate of aluminium alloys 5083-H116 was process for construction of all type of aluminium stiffener prepared at shipyard before the construction the panel. The Vickers Hardness test measurement was aluminium stiffener panel. The plate is cut and produced at allocated aluminium stiffener panel welding preparedto get the dimension based on the ship process for measurement on effected zone on panel requirement. Aluminium stiffener is resized to deduce extrusion. the parameter smaller than panel dimension suitable for g) Data Acquisation and analysis the tester machine. The methods for fabricating The analysede for bending, compression test aluminium stiffener panel are presented by MIG welding and Vickers hardness measurement has provided. The technique. numerical analysis based on the result that was c) Laboratory Test Panel obtained from the compression test is provided. The Year 2012 The aluminium stiffener panel work at shipyard theoretical modeling provided thetheoretical and as followed by determination of the type and dimension. formulation of aluminium stiffener panel compressive A three panel with L-shaped, T-shaped and flat shaped strength. The comparison data from the compression stiffeners fabricated from extruded aluminium profiles in test deduced the different of imperfection and fatigue of alloy AA5083-H116, joined by welding, was defined. material strength. The reliable effect on aluminium 12 stiffener panel from their behaviour with the d) Compression Test characteristic of each type of stiffener panel dimension The method of research to determined behavior has determined. The classification society validation Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I of materials under crushing loads. Compressive stress requirement process approval the license and ship and strain is calculated and plotted as a stress-strain seaworthiness is used for necessary checking of the diagram test purposed to determine ultimate strength of result. aluminium stiffener panel under load. The result determined when the frequency of breakage or limit of III. Result and Discussion aluminium stiffener panel test. The specimen was prepared to test at universal testing machine the best a) Stiffener Panel Dimension environmental condition. For aluminium stiffener, good Stiffener panel dimension is calculated condition and room temperature to avoid the other effect theoretically according to suggested requirement and on the test specimen is providing for the test. comparison is made. The bending test require the dimension of aluminium stiffener panel the values of e) Bending Test thickness and area of body applied load, A. The length Three-point bending test involve involved simple of specimen, L is same and width of specimen, b. The two-dimensional analysis of a simply supported range of dimension L/b is 6.9 of each specimen. aluminium stiffener panel loaded. The formation of the The total overall dimension for aluminium process zone and failure of the specimen are simulated stiffener panel is likely to be the same with the bending in aluminium stiffener dimension steps, controlled by the test. The measurement weight of specimen, W slightly displacement under the applied load. The load- different and thickness of stiffener is also different. The displacement diagram is deduced as final result for flat bar (fb) is 3mm, T-bar (tb) is 4mm and angle bar (lb) bending test. is 5mm. The range of measurement is L/b that is 0.9 f) Heat Affected Zone Test respectively. The aluminium stiffener panel has a cross The test specimen was conducted by hardness sectional area with their body platting, have the area of test to find the material properties in aluminium stiffener dimension, sectional dimension of stiffener panel and panel and material composition in the welding process. type stiffener panel difference values and arrangement. The Vickers hardness test is conducted to The cross sectional area is analysed in Table 4.3 with measuring and assesses the extent of the structural specimen is considered. Table 4.3 : Cross-Sectional Area Type Of Aluminium Stiffener Panel Cross-section (nominal values) Type specimen a (mm) b (mm) t (mm) tw (mm) hw (mm) tf (mm) bf (mm) Flar bar (fb) 345 50 4 3 51 - - T-bar (tb) 345 50 4 4 47 4 50 Angle bar (lb) 345 50 4 5 46 5 50 The requirement of body plate used is similar to (2009). Table 4.4 shows the type of aluminium stiffened other but structural strength of stiffener panel is slightly plate by type of stiffener panel. The used of average different compare to research by Khedmati M.R. et al. value of initial deflection in ship plating is investigated © 2012 Global Journals Inc. (US)
- 4. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction and evaluated by Khedmati M. R. et al as W0max = previous study. The Young modulus and the Poisson 0.05ß2t. The material properties were taken from the ratio of the material are 70 GPa and 0.33, respectively. Table 4.4 : Type Of Aluminium Stiffened plate Stiffened plate Type Specimen 4 I (mm ) r ß λ W0max/L (×10-3) Flar bar (fb) 33162.7 5.6604 0.87966 0.001023 0.449 T-bar (tb) 34607.6 5.0077 0.65974 0.001157 0.252 Angle bar (lb) 40556.7 4.8488 0.52779 0.001195 0.161 Year 2012 b) Ultimate Strength And Maximum Load On specimen test has a disturbance of stresses between 0- Aluminium Stiffener Type 1mm on deflection body because the material of plate has higher load better than load applied from the i. Bending Test machine test. The result of the ultimate load of structural Graph 4.1 shows the result of angle bar type of body is a 1083.69 kN. stiffener panel in called L shaped. The initial angle bar 13 Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I Figure 4.1 : Graph Load Applied Against Deflection Of Angle Bar Figure 4.2 has shows the graph of flat bar (fb) initial of bending test for flat bar specimen has a type of stiffener panel, the load applied against disturbance area of body plate between 0-0.7mm on deflection has proved the deflection of stiffener in the deflection body. Figure 4.2 : Graph Load Applied Against Deflection Of Flat Bar Figure 4.3 has shows the graph result of T-bar (tb) type of stiffener panel on the load applied against deflection has proved the deflection of stiffener. The T- bar result shows that the ultimate load of structural body is a 4089.146 kN. The percentage of successful of damage body required 5.12 % in area of deflection. © 2012 Global Journals Inc. (US)
- 5. Year 2012 Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction Figure 4.3 : Graph Load Applied Against Deflection Of T-Bar The final value of test response by bending test comparison has achieved their properties and strength is shown in Table 4.5. This is required to determine the values, the ultimate strength break the applied load with 14 ultimate capacity load with the sample of specimen. The the stiffener panel. Table 4.5 : The Final Value Of Test Response By Bending Test Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I Test Response Type Max. Load,k Deflection Break,k Elastic Modulus,E Yield Strength specimen (N/mm²) (mm) (N) (N/mm²) (N/mm²) Flat bar 0.051 5.952 6513.113 0.091 0.16 Tbar 0.185 15.030 36077.32 0.332 0.184 Angle bar 0.042 4.537 9445.379 0.076 0.114 The aluminium stiffener is the most important in panel for testing the strength of aluminium stiffener the local strength because the part is stable in that area panel. The higher load required for machine needs more and produced the higher strength and very reliable to applied load to damage their body until 4742.487 kN use in the bulkhead amidships to prevent the recorded. Finally the ultimate load applied with the body consequential damage from outside. 5233.571 kN for the angle bar specimen has recorded. The graph of compressive load against strain is shown ii. Compression Test in figure 4.4. The result of angle bar process has show that is 8.671 kN was used to pressure the aluminium stiffener Figure 4.4 : The Graph Compression Test Of Angle Bar The experiment of flat bar is shown, when the Finally the values of flat bar totally reduce down because first value 5.017 kN was used to pressure the aluminium of the fatigue and failure mode on the structure. The stiffener panel. The higher load required for machine graph compressive load against strain of flat bar is because the strength of body needs more applied load represented in Figure 4.5. to damage their body until 1946.741 kN recorded. © 2012 Global Journals Inc. (US)
- 6. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction Year 2012 Figure 4.5 : The Graph Compression Test Of Flat Bar The experiment has shows, that at first value of good condition because the stability of aluminium 15 T-bar it only 2.733 kN used to pressure the aluminium stiffener panel is covered all of body plate. The final load stiffener panel. The higher load required for machine of aluminium stiffener panel of T-bar becomes 5189.425 Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I because the strength of body needs more applied load kN. The graph compressive load against strain of T-bar to damage their body until 5225.155 kN recorded. The has shown in Figure 4.6. T-bar has most structural stiffener panel in stay in the Figure 4.6 : The Graph Compression Test Of T-Bar Table 4.9 showS the final result for compression test for requirement of test response determined a functional of each specimen in various side. Table 4.9 : The Final Test Response of Compression Test Test Response Type Max.load Yield point Break Extension Stress σu Strain έu E (N/mm²) Fu kb/EA (N) (N) Vu (mm) (kN/mm2) (%) (N/mm²) (fb) 20.701 19090 0.23 4696 4.661 4.690 1.165 27.33 (tb) 38.692 51449 0.43 50890 4.583 7.157 1.151 90.71 (lb) 38.138 46681 0.424 51323 4.553 7.218 1.138 92.81 The result has expected the difference in type of c) The Effect on Reliable of HAZ at Aluminium Plates aluminium stiffener panel iss defined and determine the and Stiffener Panel strength of aluminium stiffener panel in difference of The measurement of HAZ modeling with type of ultimate strength. specimen based on distance from weld centre was used © 2012 Global Journals Inc. (US)
- 7. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction to find the reliable effect of HAZ on the characteristic of each specimen type. The Figure 4.7 showS the hardness of measurement by flat bar type of specimen. Year 2012 Figure 4.7 : The Hardness Measurement Of Flat Bar 16 Figure 4.8 has shown the hardness of distance over than nearest of distance weld centre with measurement by T-bar type of specimen. The linearity the influence of HAZ is very reliable because of effect of Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I graph shows that the value of HAZ is higher that very far heat temperature of stiffener panel. Figure 4.8 : The Hardness Measurement of T-Bar Figure 4.9 shows the hardness of measurement by angle bar type of specimen with values of HAZ. Figure 4.9 : The Hardness Measurement of Angle Bar The hardness measurement in units HV3 use d) The Energy of Collision Stiffener Panel and Ship the 3kg load in Hardness test. The T bar graph show the Structure concentration value from the distance weld centre, it is The variable of aluminium stiffener panel has observed that the highest point in the hardness test required the energy of load collision in ship structure produced 997.9 in 5mm from weld centre. requirement of structural damage has reconsidered by © 2012 Global Journals Inc. (US)
- 8. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction owner ship to determine a value and loss of damage in ET (mJ) = ½ × (Mstiff V²) k -1 their body. In the element of load of collision, the theoretical modeling energy of ship tonnage and energy Eload (mJ) = ET/2 (Mstiff V²) -2 load of collision is provided by the equation: Table 4.11 : Calculation Of Energy Of Load Applied, Energy Of Collision Tonnage of ship Specimen E (kN/m²) Mstiff (kg) Fu (kN) Vu ET (mJ) Eload (mJ) (ton) 1000 14.08 211.43 2000 28.16 422.86 Flat bar 2.07 0.38 19.09 3000 42.24 634.28 Year 2012 4000 56.32 845.71 5000 70.4 1057.14 1000 14.08 1987.18 2000 28.16 3974.36 T-bar 3.81 0.72 51.44 0.16 3000 42.24 5961.54 17 4000 56.32 7948.72 5000 70.4 9935.90 Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I 1000 14.08 1627.92 2000 28.16 3255.85 Angle bar 3.87 0.64 46.68 3000 42.24 4883.77 4000 56.32 6511.69 5000 70.4 8139.61 IV. Conclusion and Recommendation accidental impact is necessary. Lastly, probabilistic approach to consequent evaluation of damaged stability a) Conclusion and vessel survivability can be researched from this The result showed that the aluminium stiffener study. panel area with lower heat is more stable and has reliability for approve in ship structural system. The ii. Acknowledge stiffener panel strength isdetermined by the ultimate strength of the load collision applied. The effect of I would like to thank Faculty of Maritime Studies stiffener height on average tears length for the weld and Marine Science (FMSM), Universiti Malaysia configuration shows increasing tearing threshold for a Terengganu for their assistance extended to facilitate decreasing stiffener height. The deformation is slightly a the journey of this Final Year Academic Projects. The symmetric with the centre in the plate and proceeds most appreciation is intended for Mr. Ir. Oladokun along the stiffener, when the tear reaches the weld it Sulaiman as supervisors who provide guidance and deviates around the weld and then proceeds along the assistance throughout this project. At same, thanks for weld and plate intersection. The importance of structural Mr Azlan b Musa as giving guidance towards this dimension of specimen prevents the outside pressure research. Also, a great thankful for the Mr Wan Mohd from structural damage and collapse. Shukri as project manager, Kay Marine Sdn Bhd in giving a lot information and prepared materials for my b) Recommendations research. Thank you again. i. The following recommendation is proposed for References Références Referencias future improvement of this study Firstly, the actual design study compared 1. Zha, Y., Moan, T. 2001. Ultimate strength of application to a ship structure design. Also, prediction of stiffened aluminium panels with predominantly the possible impact on structural design, development torsional failure modes. Thin-Walled Structures 39: arising from these conditions is that navies have 631–648. increasingly turned to the application of classification 2. Rigoa, P., Sarghiutab, R., Estefenc, S., Lehmannd, society processes and resources to help them in E., Otelead, S.C., Pasqualinoc, I., Simonsene, B.C., establishing and applying technical criteria for naval ship Wanf, Z., Yaog. T. 2003. Sensitivity analysis on design and construction including those related to the ultimate strength of aluminium stiffened panels. ship structure. Furthermore, the study of innovative Marine Structures 16: 437–468. designs for maximum the crashworthiness in an 3. Brubak, L., Hellesland, J. 2007. Semi-analytical post © 2012 Global Journals Inc. (US)
- 9. Ship Structural Integrity of Aluminium Stiffener Panel for Consequence Reduction buckling and strength analysis of arbitrarily stiffened plates in local and global bending. Thin-Walled Structures 45: 620–633. 4. Ye, N., Moan, T. 2007. Static and fatigue analysis of three types of aluminium box-stiffener/web frame connections. International Journal of Fatigue 29: 1426–1433. 5. Brubak, L., Hellesland, J. 2008. Strength criteria in semi-analytical, large deflection analysis of stiffened plates in local and global bending. Thin-Walled Structures 46 : 1382– 1390. 6. Khedmati, M.R., Ghavami, K. 2009. A numerical Year 2012 assessment of the buckling/ultimate strength characteristics of stiffened aluminium plates with fixed/floating transverse frames. Thin-Walled Structures 47: 1373–1386. 18 7. Paik, J.K., Seo, J.K. 2009. Non linear finite element method models for ultimate strength analysis of steel stiffened-plate structures under combined Global Journal of Researches in Engineering ( B ) Volume XII Issue II Version I biaxial compression and lateral pressure actions — PartI : Plate elements. Thin-Walled Structures 47: 1008–1017. 8. Sekulski,. Z. 2009 . Least-weight topology and size optimization of high speed vehicle-passenger catamaran structure by genetic algorithm. Marine Structures 22 : 691–711. 9. Khedmati, M.R., Zareei, M.R., Rigo, P. 2009. Sensitivity analysis on the elastic buckling and ultimate strength of continuous stiffened aluminium plates under combined in-plane compression and lateral pressure. Thin-Walled Structures 47 : 1232– 1245. 10. Wang, D., Ye, L., Lu Y., Su, Z. 2009. Probability of the presence of damage estimated from an active sensor network in a composite panel of multiple stiffeners. Composites Science and Technology 69 : 2054–2063. 11. Bonorchis, D., Nurick, G.N. 2010 .The analysis and simulation of welded stiffener plates subjected to localized blast loading. International Journal of Impact Engineering 37 : 260–273. 12. Rønning, L., Aalberg, A., Larsen, P. K. 2010. An experimental study of ultimate compressive strength of transversely stiffened aluminium panels. Thin- Walled Structures 48: 357–372. © 2012 Global Journals Inc. (US)