UTILIZATION OF BAMBOO LAMINATED FOR WOODEN SHIP’S CONSTRUCTION
By:
Akhmad Basuki Widodo,
Lecturer at the Faculty of Technology and Marine Sciences, University of Hang Tuah, Surabaya and
Researchers at the Ship Building Industry PT PAL INDONESIA, Surabaya E-mail: [email protected]; [email protected]
SUMMARY
Bamboo is an abundant and relatively cheap material which has better physical and mechanical properties compared to other ship-building materials such as wood or steel. It means that bamboo has greater strength per unit specific gravity. However, the use of bamboo in the field of construction especially in the marine construction has been scarce and only used as a lightweight construction.
In line with the development of lamination technology and its specific treatment, it is hoped that the utilization of bamboo can be used in the field of shipbuilding. Therefore, this study aims to determine the physical and mechanical properties of laminated bamboo compared with those of wood which has been used for the construction of wooden ships.
From the research, which utilizes Teak, Red Meranti and Mahogany, also Resorcinol formaldehyde-based type of cold press tested by using ASTM D-143 standard, it is revealed that the laminated wood and or bamboo has better physical and mechanical properties compared to solid wood. As a wooden boat material, laminated bamboo has higher strength and density compared to Teak, Red Meranti and Mahogany. Although it has higher density, the ratio between its strength and density is still high.
According to Wooden Ship BKI regulations, the use of wood with a greater density compared to the requirement, the construction size may be reduced in accordance with the ratio of its density. Therefore, laminated bamboo qualifies for a wooden boatbuilding material.
Keywords : Physical Properties, Mechanical Properties, Bamboo Laminated, Wooden Ships.
INTRODUCTION.
a. Background.
Utilization of marine resources is not maximized and just around the coastal alone, resulting in saturation (over fishing) inte coastal . One problem is the limitations in the provision of fishing facilities and infrastructure, which is capable of sailing ships minimal region of the EEZ (exclusive economic zone).
Limitations are due to too expensive materials to build fishing boats are generally made of wood, while wood is increasingly felt the more expensive. In addition to wood materials, there are actually natural resources that can replace wood as the main ingredient in the manufacture of ships.
According to the Morisco (1999) and Ananda (1996), bamboo has a tensile strength two times greater than wood. And the compression strength 10% higher than the compression strength of wood. In addition, bamboo is the fastest growing of crops and can grow up to lower mainland (near coastal) areas at an altitude above 600 meters above sea level. on the condition of the soil that are less good. Bamboo harvest time (life cicle) ranged between 3 to 5 years. Bamboo can grow 5 cm along the vertical direction for every hour.
Compared with the teak growth cycle, which can take used of requiring a minimum of 50 years, the growth cycle of bamboo is only a tenth of the growth cycle of teak. Bamboo in Indonesia reached 100 species, but which can be used for use in the field of construction is less than ten species.
Until now, the use of bamboo just made 'wastebasket' only, meaning the wider use of bamboo is still very limited. In the field of construction, bamboo is usually used as pillars, beams or scaffolding. In Indonesia, the most widely used in the field of construction is ‘bambu betung’ (Dendrocalamus asper). Dendrocalamus asper have diameter reach 15 cm, the thickness of the bamboo wall reach 2 cm and a length between nodes can reach 60 cm. Bamboo species is easily found virtually throughout the tropics.
With the known character of wooden ship structures and mechanical properties of composite bamboo, it will also get a standard strength and standard dimention of bamboo composite materials for wooden ship structural. Standard of strength covering the bending static strength and mechanical strength on the structure of the wooden ship. And the dimension standard is a standard thickness and width of the composite standard for the structure of the wooden plank and beam.
b. Goals and Objectives
The purpose of this research was to determine and analyze the physical and mechanical properties of solid wood and bamboo laminated to shrinkage and swelling, density or specific gravity, statis bending strength, tensile strength and the impact bending strength. This is due to the force or load received by the ship in general is these forces.
The goal of the research is to know the properties of the bamboo laminated that includes the mechanical properties and physical properties, it will be known parts or components of ships that can be replaced with composite material of wood and / or bamboo.
The benefits of this research was to determine and replace of the parts and components of wooden ships that will bamboo laminated.
REVIEW REFERENCES.
Research on the mechanical properties of bamboo materials has been carried out by Jansen [1980], Yap [1983], Espiloy [1985] and Morisco [1996]. From this research stated that the tensile strength and compression strength parallel to the fiber reaches 200-300 Mpa, and the elasticity of strength mpa range 80-100 mpa. But the shear strength perpendicular to the fiber is only about 2.5 mpa. Modulus of elasticity parallel to the fiber reaches 10-20 mpa.
Another advantage of bamboo is a fast growing plant species and at age 3 to 6 years of bamboo can already be utilized. Bamboo can grow 5 cm along the vertical direction for each hour (Morisco, 1999, Fangchun, 2000 and the CBRC, 2001). Compared with teak growth cycle which can take advantage of requiring a minimum of 50 years, the growth cycle of bamboo is only a tenth of the growth cycle of teak.
In the field of light constructions, bamboo is usually used as a pole, beam or scaffold (Idrid et al, 1998, Krisdianto, et al, 2000). In Indonesia there are several types of bamboo species and the most widely used in the field of construction is Bambu Betung (Dendrocalamus asper). Diameter of ‘Bambu Betung’ can reach between 12-15 cm, and the thickness of the bamboo wall reach 2 cm and a length between node (inter node) can reach 60 cm. The species of ‘Bambu Betung’ is easily found virtually throughout the tropics.
According to the Morisco (1999) and Ananda (1996), bamboo has a tensile strength two times greater than wood, while the compressive strength 10% higher than the compression strength of wood. When compared with steel which has a specific gravity of between 6.0 - 8.0 (while BJ bamboo = 0.6 - 0.8), tensile strength of the steel only amounted to 2.3 - 3.0 larger than the tensile strength of bamboo. Thus, bamboo has a tensile strength per unit specific gravity of its kind for 3-4 times greater than steel..
In addition, bamboo has a better mechanical strength compared to steel reinforced concrete. In the following picture is shown that the tensile strength of bamboo ‘ori’ almost up to 5000 kg/cm2 or almost doubled compared to the tensile strength of concrete reinforcing steel which only 3000 kg/cm2. While other types of bamboo, the ‘Bambu Betung’ (Dendrocalmus asper) has a tensile strength of 3000-3500 kg/cm2, where the strength is still better than the strength of concrete reinforcing steel (Morisco, 1999).
Figure 1. Stress and Strain Diagrams
Bamboo and Steel.
In ship building is basically the main components can be grouped into common shapes such as straight and curved and the similarity of construction such as shape boards and beams (Rosyid and Widodo, 2000).
Clasification of the main components of the ship can be seen in the table below.
Table 1. Classification of Main Components of Wooden Ship.
Type of Plank : Construction :
Straight Curved
Plank
- Watertight Bulkhead - Transom
- Planking - Deck
Beam
- Keel - Deck Beam - Beam Stringer
- Frame
Rosyid and Widodo (2000) have attempted the development of new materials through the incorporation of teak wood and bamboo with bonding (lamination) for marine applications through Competitive Research Partnership (RUK). In such activities has been developed of glue for cold-press process by the domestic industry (PT Palmolite Adhesive Industry, Probolinggo), and developed applications for the pole layer material (mast) which is required by the yacht market in Europe, Japan, and USA.
According to Chugg (1964) laminate material advantages: it can be made with a variety of shapes and sizes, the efficiency is very high raw material utilization, improving strength and increased durability and
resistance to fire. Thus laminate ‘Bambu Betung’ can be made to the size of an unlimited and appropriate with the size and shape of the ship constrauction, even though the materials used are very limited in size.
According the Bureau Classification Regulation (BKI), that the use of wood for the wooden ship based on the weight of wood (specific gravity or density). In the section that requirement a strong construction, timber should be used with a high density.
Another factor to consider in the process of lamination is the type of adhesive used. Under the terms of Classification Bureau of Indonesia (BKI) of wooden ship building regulations, the adhesive used should be type weather proof and boiling proof (WBP type), which means that the adhesive must be able to withstand the changes caused by the weather and resistant to micro-organisms and resistant to hot and cold temperature changes (BS, 1964).
Seeing the advantages of bamboo and character of laminate materials, both in terms of technical and non technical such as availability of materials, the bamboo laminated having better mechanical properties than the mechanical properties of teak wood. Bamboo Laminated wood has great potential for use in structures such as timber ships for hull boats, decks, beam girder, keel and frame.
The cross-sectional of main construction wooden ships can be seen in the picture below.
Figure 2. Across-sectional of Wooden Ship
RESULTS and DISCUSSION.
a. Physical Properties.
The first step of the research is the measurement of moisture content in each specimens, because according to Faherty (1999) that the moisture content of specimens have a significant effect on mechanical properties.
From the results of measurements of moisture content and analyzed by Completely Randomized Design (CRD), then the difference in moisture content in the specimen does not have a significant effect, because of the calculation results (F-count) showed that the differences were not significantly, both on the confidence interval 95% confidence or 99%. For more details the differences between the moisture content of the specimen can be seen in the following figure.
Figure 3. Moisture Content of Specimens
Material properties are important for the construction of wooden ships is density or specific gravity. From the measurement results obtained showed that the bamboo laminated has a higher density compared to the solid wood or wood laminated. But the difference in density after analyzed by Completely Randomized Design was not significantly, both at the confidence interval of 95% and 99%. For more details can be seen in the following picture.
Figure 4. Density of Specimens
The other phisycal properties of the material for wooden ship is the swelling and shrinkage materials at the width direction. In this direction need to know because it will affect the impermeable hull during wet and dry at the wooden ships in the full and empty load, or in a state of the waves and not taxable. So that changes wet to dry or vice versa can cause cracks in the hull section connections, therefore the material has a high shrinkage will cause a large gap and leakage will occur.
0 2 4 6 8 10 12 14 16
SOLID WOOD
LAM 3 LAM 5 BAMBOO LAM
MC (%)
T EAK RED MERANT I MAHAGONI BAMBOO
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
SOLID WOOD
LAM 3 LAM 5 BAMBOO LAM
DENSITY (kg/dm3)
T EAK RED MERANT I MAHAGONI BAMBOO
Figure 5. Measurement of Shrinkage
From the results obtained that the bamboo laminated have a smaller shrinkage than solid wood or teak, red meranti and mahogany wood laminated.
b. Mechanical Properties.
Results of Static Bending Strength testing, indicated that the bamboo laminated has higher strength than the solid wood or wood laminated. This is due to the character of bamboo have higher elasticity than the elasticity of wood, even with the steel (see figure 1).
With Completely Randomized Design analysis, indicated that the strength of bamboo laminated higher than the solid wood. It is shown the results of calculations (F-count) is higher than that the F-table.
For details the differences between the static bending strength of solid wood and bamboo laminated can be seen in the following figure.
Figure 6. Static Bending Strength
For result of tensile strength testing showed similar results with static bending strength, which bamboo laminated has a tensile strength higher than the solid wood.
This is because the properties of bamboo fibers have better tensile strength than the tensile strength as well as wood fiber. From the analysis with Completely Randomized Design, showed that the tensile strength of solid wood and bamboo laminated have differences that are not so obvious. Differences in tensile strength of solid wood and bamboo laminated can be seen in the following figure.
0 0.5 1 1.5 2 2.5 3 3.5
SOLID WOOD
LAM 3 LAM 5 BAMBOO LAM
SHRINKAGE (%)
T EAK RED MERANT I MAHAGONI BAMBOO
0 20 40 60 80 100 120 140
SOLID WOOD
LAM 3 LAM 5 BAMBOO LAM
STRENGTH (kg/cm2)
T EAK RED MERANT I MAHAGONI BAMBOO
Figure 7. Tensile Strength
Other requirement of the mechanical properties of material’s for the wooden ships is at the properties of impact bending strength. From the results of testing, indicated that the impact bending strength of the bamboo laminated has resistance at a better than solid wood. Bamboo fibers have better strength than the strength of wood fiber
Figure 8. Impact Bending Strength
CONCLUSIONS AND SUGGESTIONS.
From the test results of solid wood and bamboo laminated can be concluded that :
1. Bamboo Laminated has physical properties and mechanical properties better than the physical properties and mechanical properties of solid wood..
2. Although bamboo laminated has higher density, but the ratio between its strength and density of bamboo laminated is still high. According to Wooden Ship BKI regulations, the use of wood with a greater density compared to the requirement, the construction size may be reduced in accordance with the ratio of its density. Because with increasing strength of the composite bamboo, its use on the vessel will reduce the volume of material. So overall weight of the material will not increase.
Therefore, laminated bamboo qualifies for a wooden boatbuilding material.
0 500 1000 1500 2000 2500 3000
SOLID WOOD
LAM 3 LAM 5 BAMBOO LAM
STRENGTH (kg/cm2)
T EAK RED MERANT I MAHAGONI BAMBOO
0 10 20 30 40 50 60 70
SOLID WOOD LAM 3 LAM 5 BAMBOO LAM
STRENGTH (kg/cm2)
T EAK RED MERANT I MAHAGONI BAMBOO
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