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Composite material is a well-known structural material which is increasingly adopted as an engineering structure material. Glass fiber reinforced polymer offers the lightweight and high strength characteristics that is required for the modern industry, such as aviation, automotive, wind power, and marine technology. One of the important mechanical characteristics of the composite materials are the tensile properties, because it is well known as the material strength. Therefore, the investigation of mechanical response on the glass fiber reinforced polymer (GFRP) tensile test using numerical analysis is important for the estimation of structural response of the GFRP complex structure, such as boat construction. The objective of this research is to assess and estimate the mechanical response of the GFRP composite material subjected to tension load using finite element method. The linear transversely isotropic model is developed to estimate the unidirectional glass fiber GFRP with the configuration of fiber orientation angles of 0°, 30°, 45°, 60° and 90°. The results show that FE simulation are capable to detect the specimen response during the tensile test. The maximum discrepancy of the estimated stress strain diagram is about 16.5% to 32% compared to experimental data. The larger orientation angle has shown the larger discrepancy value. It is found that the increment of discrepancy value is generated by the nonlinearity behavior of the material due to the domination of polymer material behavior on the large orientation angle. Otherwise, the FE models have estimated accurately the ultimate strength, maximum displacement and fracture load. It can be concluded that the linear transversely isotropic model is adequately accepted as the estimation method of the GFRP composite structure response.

Hybridization of natural and synthetic fibers has the ability to improve composite performance. It means that the combination of natural fibers such as coir, jute, bamboo, and sisal with synthetic or glass fiber can broaden the role of the composite material, especially for structural application. This study developed a finite element simulation to investigate the damage to the bow structure of the fishing boat hull, which was produced using hybrid coir-glass fiber composite (HCGFRP) material subjected to front collision load. The experimental measurement was conducted to determine the mechanical properties of four hybrid composite laminates defined based on the differences in their layers number, fiber types, and orientation angle. Moreover, a numerical simulation model was applied to the traditional fishing boat colliding with fishery harbor quay, and the scenario was defined by varying the boat speed and the types of laminates adopted on the hull structure. The results showed the damage level for the bow structure of the HCGFRP boat due to the collision accidents, while the numerical findings are expected to be used as the basic knowledge in applying the hybrid coir-glass fiber laminates composite as an alternative hull construction material.

Tulisan ini menjelaskan bahwa hand sanitizer digunakan sebagai agen pembersih untuk bakteri, kuman atau virus yang bekerja secara efektif, sederhana karena dapat digunakan secara langsung tanpa harus membilasnya. Tujuan pelatihan dan pembuatan hand sanitizer adalah untuk memberikan pengetahuan dan teknologi yang tepat guna kepada masyarakat di Desa Bulusan Semarang, selain membuat hand sanitizer untuk keperluan tersebut, juga dapat dijual sehingga dapat meningkatkan pendapatan. Hasil dari kegiatan ini adalah hand sanitizer yang memiliki bau wangi peppermint dan daun sirih serta lemon, dengan pH 5 sesuai dengan standar yang ditetapkan SNI 2588-2017, ketika digunakan di tangan tidak menimbulkan iritasi.

Several advantages of multihull, such as catamaran, have been extensively discussed in the previous research. Therefore, this research focuses on developing a catamaran hull form for the fish processing vessel hull. The initial stage is determining the principal dimension and exploring the configurations of catamaran hull forms. The existing high-speed craft catamarans have been adopted to determine the parent model main dimensions using a linear regression equation model. Otherwise, the catamarans single demi-hull geometry was developed by converting and modifying the parent model hull form with enlarging the hull displacement to achieve the deadweight capacity and service speed requirements. The demi-hull spacing configuration with s/L 0.17, s/L 0.20, s/L 0.30, and s/L 0.40 on the resistance characteristics, intact stability, and sea-keeping behaviour were also explored. Furthermore, the comparisons with the previously proposed monohull were presented. Regarding the hull resistance performance, the analysis indicated that the catamaran hull form had better total resistance characteristics than the monohull on the service speed over 23 knots. In the case of intact stability, the analysis results presented that the catamaran hull form has better intact stability characteristics than the monohull. The dynamic stability of the catamarans also gave better dynamic stability at the heeling angle below 41.57°. Otherwise, the catamarans with s/L 0.17 and s/L 0.20 have lower dynamic stability than the monohull at the heeling angle larger than 41.57° and 58.03°, respectively. In the sea-keeping performance, the catamaran hull has shown an excellent rolling motion required for the offshore environment loading/unloading process. The large demi hull spacing of the catamarans hull can reduce the effect of the wave creating load on the roll motion response at the Beam Sea.

As a sovereign maritime country, Indonesia has an obligation to protect, maintain, and manage marine and fishery resources. Patrol boats as the primary means of monitoring marine and fishery resources are needed in response to several problems and threats that may occur, such as illegal fishing, destructive fishing, violations of zoning in fisheries conservation areas and others. Apart from having to be adequate on the number of units, the patrol boats must also have suitable technology to support pursuit operations and suppress violations. The main objective of this research is to investigate the total resistance and intact stability behavior of the developed axe bow hull geometry for the patrol boat hull. The preliminary design is started with the determination of the principal dimension of the patrol boat. Then the hull geometry configurations were made with the variation of the depth of bow and the water line spline type. In the case of the depth of bow, the bow with the additional depth of 30%, 40% and 50% of the draft was investigated. Otherwise, the water line spline type was configured as convex spline, concave spline and straight spline. According to the numerical analysis, the axe bow hull with the depth of bow of 30% and the straight spline type was presented the smallest total resistance performance. However, in the case of intact stability performance, all developed axe bow hull presented a similar righting moment lever arm (GZ curve). It is indicated that the total resistance of the axe bow hull is influenced by the depth of bow and water line spline type. Furthermore, those variables have a slight influence on intact stability performance.

This research is focused on the development of the design and prototype of monohull fish processing vessel hullform to support fishing activities such as catching fish, collecting fish from the smaller boats and processing fish catches. The extensive on-board facilities in the fish processing vessel are maintaining the freshness of the catch and improving the quality of catch fish than traditional fishing boat. The initial stage of this study is determining the principal dimension and exploring of the configurations of monohull hull forms. Furthermore, the investigation of resistance characteristics, intact stability and seakeeping behavior was carried out using strip theory and computational fluid dynamic methods. Regarding the performance of the hulls resistance, the analysis indicates that the hull form with smaller block coefficients showed better resistance characteristics. In the case of intact stability, the results of the analysis showed that the model 2 of monohull hull form showed better intact stability characteristics compared to the other models.

The main objective of the research was to investigate the structural response of the Glass Fiber Reinforced Plastic modular pontoon unit due to the impact load during the drop test. The impact load was defined as the drop phenomena that might be occurred while GFRP modular pontoon unit is being packaged, stacked and transported. Numerical simulation was performed using nonlinear finite element method to obtain the response characteristics. The maximum effective (Von Mises) stress of the GFRP modular pontoon unit was estimated as a design consideration for the structure strength. The external dynamics parameter which includes as the drop orientation and drop velocity which is equivalent to the drop height is being considered on the simulation analysis. According to the simulation result, it can be found that the maximum effective stress is occurred on the corner side drop position. The magnitude of maximum effective stress is larger than the yield strength of the GRFP material. Therefore the plastic deformation is observed on the corner side of the modular pontoon unit. The results of simulation analysis present that the most vulnerable drop position is the corner side position. It is recommended that the corner side of the modular pontoon unit is the important part for design improvement to increase the structure reliability during the drop phenomena.

In 2016, the Laboratory of Ship Structures and Construction Diponegoro University organized a research group to develop an alternative hull form for the tsunami lifeboat. The research group proposed a cone capsule shaped portable tsunami lifeboat to support tsunami evacuation system, especially to give a portable protection facility that easily accessed by disable person, senior citizens and children.In order to fulfill the requirement that the lifeboat structure should be able to withstand the impact load, the aimed of the study is focused on the performance of the drop impact test of the developed portable tsunami lifeboat using numerical simulation.The tsunami lifeboat has to maintain its structural integrity when dropped on 3m free fall height. The orientation configurations are considered for the numerical analysis includes end drop, side drop and reversed drop. The explicit finite element with penalty method contact analysis is used to evaluate the drop test performance.The results show that the maximum effective stress and plastic strain is found in the side drop condition.It is indicated that the side structure is more vulnerable than the top and bottom structure. The maximum absorbed rupture energy is occurred on the frame structure for reversed drop condition, however it is transmitted effectively to all of the connected frames, outer-shell and inner-shell structures. According to the results of simulation analysis, it can be concluded that the structure of the cone capsule tsunami lifeboat is reliable to withstand the severe load during the tsunami disaster.

Since roro passenger ships have specific characteristics in handling cargo with the roll-on-roll-off loading and unloading system that must be equipped with a ramp door. Therefore, it is important to conduct the ultimate strength analysis by considering local loads and global loads to ensure the level of safety and reliability of the ship structure. The aim of this research is focused on the investigation of the structural response and the ultimate strength of the roro passenger ship using the non-linear finite element method. The dynamic explicit method is conducted to estimate the large displacement of the deformed structures such as the hull girders, deck girders and plates. In the structural response analysis, the results shows that maximum stress was occurred on the deck girders due to the sagging bending moment load. In the ultimate strength analysis, it is identified that hydrostatic load have reduced the ultimate strength about 33 %. Otherwise, the ultimate strength is increased about 1 %, in the sagging condition. HIGHLIGHTS The nonlinear behavior of the roro passenger ship ultimate strength due to the combined global and local load is presented On the hogging condition, the addition of local load (hydrostatic pressure) reduce the roro ship ultimate strength about 33 % compare to the pure global ultimate bending load On the sagging condition, the hydrostatic pressure have slightly increased the ultimate strength around 1 % GRAPHICAL ABSTRACT

Permintaan pasar kerajinan batu ambar yang begitu besar membuat UKM “Amber Biru” masih kewalahan dalam mengejar proses produksi perhiasaan batu ambar.Peningkatan produktivitas diharapkan dapat dicapai melalui perbaikan pada proses polishing batu ambar. Perancangan alat yang menunjang proses penghalusan dan pengkilapan dilakukan dengan menggunakan penggerak dinamo seperti halnya mesin gerinda. Namun mata gerinda memiliki kekasaran yang tidak dapat digunakan sebagai alat poles, sehingga diperlukan proses modifikasi agar dapat memenuhi kebutuhan proses polishing dan pengkilapan yang berkualitas. Upaya pengembangan peralatan polishing dalam kegiatan pengrajin batu ambar di lingkungan UKM “Amber Biru” dan Kelompok Binaan-nya “Ambar Bulusan” menjadi fokus penelitian ini. Peningkatan produktivitas produksi perhiasan batu ambar akan dicapai melalui rancang bangun peralatan polishing yang handal, efisien dan ergonomis.

Berdasarkan hasil observasi di lapangan dan diskusi dengan kelompok pengrajin flanel yang tergabung dalam UKM “Toko Ijo Asesoris” yang berlokasi di Bukit Kencana Jaya, Kelurahan Meteseh, Kecamatan Tembalang, Semarang mengakui adanya beberapa persoalan yang dihadapi dikalangan pengrajin flanel yaitu: terjadinya ketidakakuratan dalam proses pemotongan dengan menggunakan gunting, sehingga menyebabkan banyak bahan flanel yang terpaksa harus dibuang atau dimanfaatkan untuk sesuatu menurunkan nilai produk.Upaya peningkatan produktivitas melalui pengembangan dan penerapan alat potong kain mekanik untuk bentuk pola akan menjadi fokus penelitian ini. Penerapan alat potong mekanik diharapkan dapat meningkatkan kecepatan potong dan menurunkan kesalahan akibat pemotongan secara manual dengan menggunakan gunting khusunya bagi pengrajin pemula

In the North Coastal Region of Central Java, the traditional fishing boat is a primary object that generates the economics activities of the social community. As an artisanal fishery, the boats generally adopt the tradition to build technique from their predecessor. Therefore the lack of practice to determine the propeller design which considered the hydrodynamic relation within the boat dimension, hull form geometry and propeller is observed. Presently, there is no a standard propeller design that particularly well designed considering the hull shape geometry for the traditional boat. The aim of the research is to identify the propeller that would be applied to the fishing boats typically found in the North Coastal Region of Central Java using B-Series marine propeller. Computational Fluid Dynamics (CFD) analysis for assessing the performance of thrust and torque of the developed propeller was performed.

This study has aimed to analyze the effect of alkali treatment and drying method on the surface morphology and tensile properties of single coir fibers. The treatments of the coir fibers have been configured on the concentration of alkali solution, the soaking period, and the drying method. Furthermore, they have been soaked in 2 wt% and 6 wt% sodium hydroxide solution at room temperature for 1- and 2-hours soaking periods. The drying procedures adopted have been air, oven, and sun-drying. Observations with a scanning electron microscope (SEM) show that the coir surface is coarser, especially on fibers treated with 6 wt% sodium hydroxide solution. The properties such as tensile strength and strain, as well as tensile modulus of the different samples have been measured. The results have showed that the treated coir fiber with the 2 wt% concentration alkali solution has lower tensile strength than the untreated one. The treated coir with 6 wt% sodium hydroxides has the most considerable tensile strength. The effect of the soaking period on the tensile properties has been influenced by the drying method. Therefore, the appropriate combination of the soaking period and the drying method increase single coir fibers tensile properties. Slow drying (air-drying) has generated better tensile properties than the fast method (oven and sun-drying).

In the shipbuilding and ship repair industry, the most common surface preparation technique used is abrasive blasting. The abrasive blasting and the other surface preparation techniques are the significant sources of shipyard waste and air pollution. The one of any kind techniques to reduce the hazardous air contaminant associated with the abrasive media is blasting room. The abrasive blasting operation is isolated by the blasting room to reduce the exposure to the shipyard environment. The portable blasting room design has been developed using the modular wall panel system. The research is focused on the strength analysis of portable modular blast room using glass reinforced plastics as the wall panels. The research method has two main steps during the strength analysis of the portable blast room. At first, the geometric form of the modular blast room was developed and defined to obtain the finite element model. Secondly, the load and boundary condition was defined, considering the wind load and the structure weight which are exerted to the blast room structure. The displacement method was adopted for the numerical analysis.

The size of net cages increases rapidly, reaching volumes above current experience. More exposed locations are used for fish production, introducing higher loads on the net cage and fish farm from strong water currents and large waves. Strength analysis can be a useful tool for development of net-cage designs to avoid escape of fish and ensure sufficient volume for good fish welfare and water quality. The main objectives of this research are to investigate the structural response of modular pontoon collar floating cage due to the current load to support the fish farming activities. Strength analysis was performed using commercial explicit finite element software to calculate the distribution of loads in the net cage due to current, weights and gravity. The net cage was modeled using truss elements that represented several parallel twines. Sub-elements allowed the trusses to buckle in compression, and only negligible compressive forces were seen in the numerical results. Resulting drag loads and cage volume were shown to be dependent on the net cage size and collar shape.

Composite materials have offered some improvements on the performance of hydrodynamic and structures of marine constructions. The high strength to weight and stiffness to weight ratio might be tailored through the exploitation of the fiber orientation in order to reduce the load and the stress distribution of the structure. In order to fully explore the performance of the developed glass fiber reinforce plastics (GFRP) B-series propeller for traditional purse seine boat in the North Coast of Central Java, the aim of the research is focused on the comparison of the rigid and the flexible model adopted for the simulation analysis of the propeller performance. The thrust force, the torque moment and the efficiency of the two propeller models are discussed.

Recently the diversity of fish populations in the waters Karimunjawa Island is only appreciated by those who have the ability to play diving and snorkeling. It is due to the unavailability of a vehicle that is specially made to delight in the fascination of the underwater panorama. One of the alternative solutions is using the glass bottom boat technology which is using transparent bottom that might look out the underwater scenery instead of swimming and snorkeling. The paper has focused on the study of intact stability and seakeeping characteristics of glass bottom boat trimaran in Karimunjawa Island. The intact stability characteristics will be investigated at the various load cases and weight distribution configurations which are influenced by the passenger positions and fuel tank condition. Regarding the seakeeping performance analysis, the ITTC-Bretschneider will be adopted as the wave spectrum at the wave parameters defined from the operational environment. The influence of the parameters on the stability and seakeeping of the glass bottom boat trimaran are presented and discussed.

Modular floating pontoon is a floating device commonly used as civil and marine construction. Pontoon is usually made of steel and high-density polyethylene (HDPE). Although the steel and HDPE has its own advantages and disadvantages in terms of economic, strength, and capacity. However the study of alternative raw materials for modular floating pontoon construction as multipurpose floating equipment is needed. Ferrocement which is familiar in the used for building construction material is an alternative material. Since the material is easy to find and it is such a versatile material that can be mass produced and has the mechanical strength that is simillar to steel and other materials. Following that condition the research is focused on the application of ferrocement technology for modular floating floating pontoon. The results show that the principal dimension of modular floating pontoon are length 80 cm, width 80 cm, height 75 cm, with the lightweight draft of pontoons is 30 cm. The material proportions for the modular floating pontoon are sand 48.2%, cement 34.5% and water 17.3%. Modular floating pontoon series consists of four Pontoons Square compiled with interlink (hook) so that the total of the package pontoon has a 160 cm long, 160 cm wide and 75 cm high.

Aulia Windyandari, in paper simulation model of development method for passenger savety evaluation of freefaal lifeboat explain that since the launching procedure of Freefall Lifeboat (FFL) may have an impact with the water surface, the occupant injury is possible be occured in the evacuation process of the offshore structures. The FFL shock acceleration has been conducted by the impact force when the lifeboat entry the water surface. If the shock acceleration over the human conciousness allowance, the serious injury will be happened during the FFL launching.According to the conditions, the IMO regulations have standard for the acceptance criteria of FFL shock acceleration induced by water entry impact load. The results measurement of Combined Acceleration Ratio Index (CAR) or Combined Dynamic Response Ratio Index (CDRR) should be comply with the IMO index criteria.In this paper, the methodology of FFL acceleration response prediction by the simulation model analysis will be proposed. The simulation model will be developed by using LS-Dyna code. The Simplified Arbitratry Lagrangian Eulerian Coupling will be used to define the coupling analysis between the Lifeboats (Lagrangian elements) with Water Fluids (the Eulerian Elements)Keywords: Free Fall Lifeboat, Response Acceleration, Impact Load

The freefall lifeboats have been designed to be fast and reliable evacuation system. Once the occupants have gone onboard, the lifeboat is simply sliding from a skid before the freefall. Some second after the water impact, the propulsion system can be started and the lifeboat can sail away from parent vessel. During the launching process, trajectories of freefall lifeboats can be divided into such categories, depending on the headway and advance speed after water entry and surfacing of the lifeboats. The aim of the paper is investigating the influence of the launching parameters such as, sliding distance, angle of skid and the falling height on the motion pattern of the freefall lifeboats by using Fluid Structure Interaction (FSI) analysis. The fluid structure interaction analysis is simulated using penalty coupling algorithm. The fluid is treated on a fixed mesh using a Single Material Arbitrary Lagrangian Eulerian formulation and the lifeboat structure on a rigid shell element mesh using a Lagrangian formulation. The results of the numerical simulations provide the magnitude of launching parameters for safely launching of the freefall lifeboat.