In addition to corrosion, the use of steel as a material on offshore structures also has a significant effect on the loads carried by the structures, especially at the top of the platform. Fiberglass reinforced can be divided into many categories based on the mixture of fiberglass with other materials. One of the applications of GFRP in offshore structures is to replace steel gratings with GFRP gratings used as a drain cover on the offshore platform.
One of the tests is the performance of GFRP under abrasive conditions, which investigates the effectiveness and impact of the GFRP grating under abrasion. Apart from the fact that the steel will be subject to corrosion, another problem with using a large amount of steel as an offshore material is the increase in bulk weight on the top side of the offshore platform. The scope of the study is to determine the performance of GFRP materials under abrasive conditions.
RELEVANCY OF THE PROJECT
To perform abrasion resistance test on GFRP materials, consisting of polyester, vinyl ester and phenolic, using an abrasion resistance testing machine according to ASTM G65 standard. To identify the best GFRP materials under abrasive conditions, three different resins were used: polyester, vinyl ester and phenolic. In addition, these materials are also immersed in salt water with a controlled temperature and time according to the Arrhenius equation to accelerate the aging of the materials.
Then the same test will be tested and the wear and time relationship will be identified in this project. With all the necessary experimental laboratory equipment such as the wear test machine, sieving and aging test tank available in UTP, it is believed that this project is feasible in terms of resources. In terms of time, the research should be completed within 28 weeks, where the first 14 weeks will focus on developing the wear machine, while the last 14 weeks will focus on experimental GFRP samples.
Fiber-reinforced polymer (FRP) is a polymer matrix resin reinforced with fibers and has a lower modulus of elasticity compared to steels. Fiber reinforced polymer (FRP) can be composites consisting of glass, carbon and aramid, where the fibers remain bonded together in a matrix of epoxy, polyester, vinyl ester and many other resins. Nowadays there are many applications that use fiber reinforced polymer as one of their essential materials in their products.
The properties of the fiber reinforced polymer are highly dependent on the amount and type of polymer used in the composite. Although fiber-reinforced polymer has many advantages, there are disadvantages in using fiber-reinforced polymer, especially when used in structural reinforcement [5, 6]. One of the examples is polyester fiber reinforced polymer that exhibits brittle failure under normal working conditions .
GLASS FIBER REINFORCED POLYMER (GRFP) .1 GLASS FIBER
Then the shape of the final product is determined by the configuration of the mold, and the resin is then polymerized. Depending on the chemical structure, polyester can be a thermoplastic or thermosetting, there are also polyester resins that are hardened by hardness, but the most common polyester is thermoplastic. Polyester is probably the most consistent in terms of the process by which it is polymerized.
They are easy to handle at room temperature and have similar mechanical properties to epoxy resins. Other thermosetting resins, such as epoxies or urethanes, may be more flexible than phenolic resins, but are only used in limited finishing applications. When testing the abrasiveness of samples, there are many international standards that can be used as a guide, such as the American Society for Testing and Materials (ASTM), the International Organization for Standardization (ISO), the Japanese Standards Association (JSA), the German Institute for Standardization (DIN ). ) and many others.
This test method can be carried out in the laboratory to determine the abrasion resistance of the samples using dry sand and a rubber wheel. The force applied to press the test piece against the wheel is 130 N and the test is carried out at 6000 revolutions of the wheel at 200 rpm. The sample is weighed before and after the test and the weight loss can be used directly or converted into volume loss .
The abrasive is introduced between the test specimen and a rotating wheel with a rubber band or rim of a specified hardness. The rotation of the wheel is such that its contact surface moves in the direction of the sand flow. Note that the axis of rotation of the lever arm lies within a plane approximately tangent to the rubber wheel surface, and perpendicular to the horizontal cross-section along which the load is applied.
The duration of the test and the force exerted by the lever arm vary according to the sample category.
- RESEARCH METHODOLOGY
- Abrasion Testing Machine Dimension and Components
Therefore, the rubber wheel used should have the optimum hardness of the cured rubber, such as Durometer A-60, a range of A58 to 62 is acceptable. When preparing for the experiment, all parameter measures must be fully defined and tested. Because this experiment was performed with different standards of the machine, it is very difficult to meet all the parameters of the ASTM G65 guideline.
Therefore, some adjustments need to be made, but the test procedures and objectives will be the same as ASTM G65. The guideline calls for the test to be performed with a force of 130 Newtons against the sample, 2000 wheel revolutions and 1436 meters of linear abrasion with a constant 200 revolutions per minute of wheel rotation. Although these stated parameters are very difficult to achieve, the main point of the test is to determine that the mass loss of the sample under standard linear abrasion is achievable.
Therefore, for this experiment, a load of 120 Newtons will be applied with 700 rpm of wheel rotation, because this is the limit of the performance of AC motor drives. Due to the increase in revolutions per minute, the duration of the experiment will be shorter. The duration is calculated based on the linear abrasion of the wheel, that is, the linear abrasion achieved is 1436 meters.
The starting speed of the motor can be controlled by the AC motor drives, the frequency of which can be set from 0.0 to 600 Hertz. But through this experiment the speed and revolution per minute of the engine under the load acting on it, more important. This tachometer is positioned perpendicular to the engine to measure the revolutions per revolution of the wheel. minute.
Measure the final weight of the sample and compare the initial weight and the final weight to obtain. The specimen holder is attached to the lever arm to which weights are added, so that a force is applied along the horizontal diametrical line of the wheel. The figure illustrates that the tachometer is used to determine the rotation of the tire wheel.
RESULT AND DISCUSSION
WEIGHT OF MOLDED GFRP SPECIMENS BEFORE AND AFTER AGING
From graph 4.1.1, we can see the differential weight of the GFRP specimens before and after the specimens go through the aging process, where the specimens are soaking in salt water at a temperature of 60 degrees Celsius for 2 months. From the recorded data, the polyester specimens had shown slightly decreasing weight after undergoing the aging process. Vinyl ester and phenolic had shown weight gain after undergoing the aging process.
For the vinyl ester there is a slight weight increase of about 0.25g, while the phenolic examples have increased by about 5.245g. In addition, by observation, the aging process of the samples caused the degradation of the surface of the samples and the change in color. This may be due to the salt water and temperature used during aging, which caused a change in the surface of the samples.
CALCULATING AND REPORTING RESULTS
Figure 4.3.1 shows that polyester has the least average mass loss, namely 3.84 g compared to other resins. The polyester has the least volume loss compared to the other resins. This shows that the cast polyester has the highest wear resistance compared to cast vinyl ester and cast phenolic. Figure 4.4.1 shows that polyester has the least average mass loss, namely 4.11 g compared to other resins.
The polyester has the least volume loss compared to the other resins. This shows that the pultruded polyester has the highest wear resistance compared to pultruded vinyl ester and pultruded phenol. Average adjusted volume loss after 2 months of cast GFRP soaked in salt water at 60 degrees Celsius. Figure 4.5.1 shows that polyester has the least average mass loss, namely 3.11 g compared to other resins.
The phenol shows the highest mass loss compared to the polyester and vinyl ester, which is 6.365 g. Based on the result, the polyester and vinyl ester have almost the same volume loss, which means that both samples have the same strength to resist abrasion. Based on figure 4.5.5, the comparison between adjusted volume loss of control molded GFRP and 2 months aging molded GFRP has been made.
For the polyester type samples, the control cast adjusted volume loss is 1982.98 mm 3 and the aging adjusted volume loss is 1667.53 mm 3 . The difference between control and aged specimens is 315.45 mm3, which shows that the control shaped polyester GFRP specimen has higher adjusted volume loss compared to the 2 months aged polyester GFRP specimen. For the vinyl ester type samples, the control vinyl ester sample has 2014.79 mm3 adjusted volume loss and the aged vinyl ester sample has 1686.607 mm3 adjusted volume loss.
As with polyester, the aging vinyl ester shows the lowest loss in adjusted volume loss, which is 328.183 mm3 less than the vinyl ester control sample. For the wine ester, the pultruded has a higher adjusted volume loss compared to the molded sample by 415.27 mm3. In the case of phenol, the control showed a higher adjusted volume loss compared to the pultruded one by 919.3 mm3.
CONCLUSION AND RECOMMENDATIONS
19] Free Dictionary by Farlex, Wear Resistance, Retrieved September 4 at 04:00, http://encyclopedia2.thefreedictionary.com/Wear+resistance.