Stiffened panels are fundamental structural components that maintain the integrity of engineering structures subjected to torsional loading, making accurate strength assessment essential in design and evaluation. Conventional finite element method (FEM) analyses often involve complex geometric modeling and extensive pre-processing, which can reduce efficiency and limit practical applicability. This study presents a structured FEM-based framework supported by a Python-based interface that streamlines model generation while preserving analytical rigor. The interface assists in geometry definition, meshing, material assignment, and boundary condition implementation, thereby improving consistency and reducing pre-processing time without altering the numerical formulation. Nine stiffened panel configurations were investigated by combining three plate thicknesses with three longitudinal stiffener geometries. The results indicate that increasing plate thickness significantly enhances torsional resistance. Stiffener geometry also markedly influences structural response: the 80 & times; 80 & times; 8 stiffener provides the highest resistance under general torsional loading, whereas the 100 & times; 65 & times; 9 stiffener exhibits superior performance under pure torque conditions. Overall, the results demonstrate that the proposed framework provides a consistent and efficient approach for evaluating the torsional strength of stiffened panels.

Abstract The reliability of ship structures is essential for marine safety and operational efficacy, especially in extreme weather conditions. This study evaluates the dependability of corvette ship structures under random wave stresses. Two types of random load data, namely load stress and structural strength, could be examined and subsequently quantified into the relevant probability density function (PDF). Ansys AQWA use the Boundary Element Method (BEM) to compute sea loads, encompassing vertical and horizontal bending moments, in addition to torsional moments. The structural strength was assessed by referencing published material tests that included adjustments for residual stress and corrosion. The PDF of load and strength, expressed in stress units, were determined using normal and Rayleigh distributions. The Mean Value First Order Second Moment (MVFOSM) method was employed to evaluate the reliability of the ship structure and establish the safety index for different wave conditions and material properties. The research determined that utilizing AH36 material in the structure yields the most reliable conditions at a wave height of 4.2 m, with a safety index (β) of 3.68. The critical circumstances arise at a wave height of 5.5 m with ABS A material, where a negative β signifies an unstable structure. The selection of appropriate materials and scantlings was essential in the structure of ship to guarantee their safety during.

Stiffened panels are essential structural elements that play a critical role in maintaining the integrity of engineering structures, particularly when subjected to torsional loading. Ensuring their adequate strength is therefore a fundamental requirement in design and assessment. Conventional approaches to strength evaluation using the finite element method (FEM) often face challenges due to the complexity of modeling stiffened geometries and the time-consuming setup required, which can reduce efficiency and limit accessibility for practical applications. To overcome these limitations, this study introduces the development of a graphical user interface (GUI) specifically designed to facilitate FEM-based strength analysis of stiffened panels under torsional loads. The GUI, implemented in Python, automates essential modeling steps, streamlines the input process, and enhances user interaction through an intuitive interface, thereby making torsional strength analysis more efficient and user-friendly. Numerical simulations were carried out on nine panel configurations, systematically combining three variations of plate thickness with three variations of longitudinal stiffener geometry. The results demonstrate that plate thickness has a direct influence on torsional resistance, with thicker plates exhibiting significantly higher strength, while stiffener design was also found to strongly affect performance: the 80 x 80 x 8 stiffener provided the greatest resistance against general torsional loading, whereas the 100 x 65 x 9 stiffener displayed superior behavior under pure torque conditions. These findings are consistent with theoretical predictions, confirming the reliability of the developed approach, and overall, the proposed GUI proves to be an effective tool in supporting FEM-based strength assessment of stiffened panels, offering both accuracy and efficiency while highlighting the potential of integrating computational modeling with user-oriented interfaces to broaden the applicability of FEM in structural engineering practice, particularly in analyzing complex torsional behaviors of stiffened panel systems.

Sektor kopi nasional, meskipun berposisi sebagai produsen global, masih menghadapi tantangan substansial pada level Usaha Mikro, Kecil, dan Menengah (UMKM), terutama terkait konsistensi mutu dan nilai tambah produk. Di Kecamatan Singosari, Kabupaten Malang, kendala utama yang teridentifikasi adalah praktik roasting yang masih tradisional dan tidak terstandar, mengakibatkan fluktuasi kualitas dan kesulitan menembus pasar premium. Selain itu, akses terhadap alat roasting modern berbiaya tinggi menjadi hambatan finansial yang signifikan bagi pelaku UMKM skala kecil. Kegiatan pengabdian masyarakat ini merespons kebutuhan tersebut melalui intervensi komprehensif: pengembangan alat roasting kopi inovasi berbasis monitor mekanis sederhana dan pelaksanaan program edukasi terstruktur. Alat inovasi dirancang dengan konsep compact integrated layout, menampilkan efisiensi ruang optimal, serta menggunakan borosilicate glass sebagai roasting chamber untuk transparansi visual dan monitor proses yang stabil. Selain pendampingan alat, workshop teori dan praktik diselenggarakan untuk meningkatkan pemahaman peserta mengenai parameter roasting (suhu, waktu, crack). Luaran yang diharapkan memicu kemandirian produksi melalui pemanfaatan teknologi tepat guna yang terjangkau.

Indonesia is an archipelago country which has more sea than land area that become a maritime trade route, so it is necessary to improve the safety of ship navigation, such as with ship detection for ship monitoring. As technology develops, remote sensing can be utilized in the maritime field using SAR data for ship detection. With the current advanced technology of computer vision, object detection can be progressively done using deep learning. The capture of these objects especially in the sea can be provided by SAR space-borne images. This research focuses on ship detection using variety of YOLO with 3 different datasets, such as model 1 using Sentinel-1 image with RGB composite which Sigma Nought VV polarization for red, Sigma Nought VH polarization for green, and Sigma Nought VV/VH polarization for blue. While Official-SSDD was used in model 2, and a combination of Sentinel-1 using Sigma Nought VH polarization and Official-SSDD was used in model 3. Then, ship detection model evaluated and validated using AIS (Automatic Identification System) data. The result shows Model 3 on YOLOv9 is the best model for ship detection in Surabaya area with mAP 43.90

The transition towards Net Zero Emissions (NZEs) is being accelerated by hybrid renewable technologies such as Floating Photovoltaic (FPV) systems and marine current turbines, which combine solar panels and cross-flow marine turbines mounted on floating structures for near-shore applications. Despite their innovative potential, these renewable technologies face significant challenges in stability and durability due to the effects of wind, waves, and ocean currents. Therefore, a flexible mooring system is essential to address these challenges. This research examines the influence of variations in the number of mooring lines and wave direction on the hydrodynamic response of FPV systems. Utilizing a catenary mooring system consisting of anchors, mooring lines, floats, and connectors, the study evaluates various configurations to determine the optimal solution for enhanced motion stability. Computational Fluid Dynamics (CFD) simulations are employed to analyze the dynamic response of FPV systems under different environmental conditions, represented on a sea-state scale, with a focus on pure oscillatory motions: heave, roll, and pitch. The findings aim to provide valuable insights for the design and operation of more stable and efficient FPV systems in marine environments, thereby supporting the advancement of sustainable renewable energy.

This research explores the application of NiTiNOL-steel (NiTi–ST) wire ropes as nonlinear damping devices for mitigating vibrations in composite stiffened panels. A dynamic model is formulated by coupling the composite panel with a modified Bouc–Wen hysteresis representation and employing the first-order shear deformation theory (FSDT), based on Hamilton’s principle. Using the Galerkin truncation method (GTM), the model is converted into a system of nonlinear ordinary differential equations. The dynamic response to axial harmonic excitations is analyzed, emphasizing the vibration reduction provided by the embedded NiTi–ST ropes. Finite element analysis (FEA) validates the model by comparing natural frequencies and force responses with and without ropes. A newly developed experimental apparatus demonstrates that NiTi–ST cables provide outstanding vibration damping while barely affecting the system’s inherent frequency. The N3a configuration of NiTi–ST ropes demonstrates optimal vibration reduction, influenced by excitation frequency, amplitude, length-to-width ratio, and composite layering.

Sandwich panel structures offer high structural efficiency and are increasingly used in ship superstructures. This study investigates the impact performance of a V-Core sandwich panel with varied faceplate and core thickness. The VCore configuration shows superior crashworthiness, achieving a peak force of 242 kN and Specific Energy Absorption (SEA) of approximately $0.575 \mathrm{~kJ} / \mathrm{kg}$. Analysis of deformation patterns and velocity graphs reveals an effective distribution of plastic deformation across the faceplates and core, contributing to significant energy dissipation. These results demonstrate that V Core successfully combines structural strength with lightweight efficiency, making it a promising design for resisting highvelocity impact loads in marine applications.

Floating photovoltaic (FPV) systems offer a promising renewable energy solution, particularly for coastal waters. This preliminary numerical study proposes a single-array pentamaran configuration designed to maximize panel installation and enhance stability by reducing rolling motion. The study investigates the effect of mooring length on the motion behavior of FPV systems and actual line tension using the Boundary Element Method (BEM) in both frequency and time domains under irregular wave conditions. The results demonstrate that the mooring system significantly reduces all horizontal motion displacements, with reductions exceeding 90%. Even with a reduction of up to 51% in the unstretched mooring length, from the original design (304.53 m) to the shortest alternative (154.53 m), the motion response shows minimal change. This is supported by RMSE values of only 0.01 m/m for surge, 0.02 m/m for sway, and 0.09 deg/m for yaw. In the time-domain response, the shortened mooring line demonstrates improved motion performance. This improvement comes with the consequence of stronger nonlinearity in restoring forces and stiffness, resulting in higher peak tensions of up to 15.79 kN. Despite this increase, all configurations remain within the allowable tension limit of 30.69 kN, indicating that the FPV’s system satisfies safety criteria.

BUMDes Mutiara Saghara mengembangkan usaha baru berupa Eduwisata Garam, yaitu wisata edukasi yang memperkenalkan proses pengolahan garam rakyat secara tradisional serta inovasi modernnya. Meskipun sektor garam berpotensi meningkatkan perekonomian warga Desa Bunder, saat ini kontribusinya masih belum optimal. Akibat dari minimnya kontribusi ini, produksi garam oleh petani tidak memberikan keuntungan ekonomis yang signifikan. Untuk mengatasi permasalahan tersebut, program pengabdian kepada masyarakat ini bertujuan mengintegrasikan sistem desalinasi air laut yang menghasilkan garam dan air hasil evaporasi. Pengabdian dilakukan secara bertahap mulai dari mendesain alat, mengadakan bahan baku, membuat alat, melakukan uji alat dan menyerahkan alat kepada mitra. Dalam proses utamanya, air hasil evaporasi yang memanfaatkan panas matahari akan dialirkan melalui pipa saluran ke bak penampung dan kemudian diproses dengan teknologi reverse osmosis (RO) untuk menghasilkan air bersih. Inovasi ini diharapkan dapat meningkatkan kualitas garam dan memberikan manfaat lain yaitu dapat menghasilkan air bersih. Sistem RO dirancang dapat menghasilkan air bersih 1000 gpd.

Energy supply is a critical variable affecting modern life. Indonesia has many renewable energy sources. One of them is ocean currents. Savonius turbines, which are effective in low-speed currents, have been widely studied in their vertical form, but there has been little progress on cross-flow Savonius turbines. In this study, the turbine performance was investigated in by observing the behaviour caused by the influence of depth immersion, given that the surface of the submersible medium and the surface of the bottom can influence the turbulence. Therefore, the cross-flow Savonius turbine was placed in three different depth conditions: 33%; 50% and 66% of water depth. An analysis was done with Computational Fluid Dynamics (CFD) software. The turbine's rotation direction was also set in two conditions (clockwise and counterclockwise). All these scenarios resulted in the turbine with 66% and the clockwise condition showed the highest results with a Coefficient of power (Cp) value of 0.249. The vortices flow pattern created by the clockwise configuration tended downward, in contrast to the counterclockwise which pointed upward. The cross-flow Savonius turbine worked optimally in a low Tip Speed Ratio (TSR) where its performance was greatly affected by torque.

Floating photovoltaic (FPV) systems offer a viable renewable energy solution due to easy installation and cost-effectiveness compared to other renewable energy generation methods. On the other hand, land-based solar photovoltaics face challenges such as space scarcity and environmental impacts. Shifting to nearshore locations unlocks vast ocean space potential, though waves expose significant challenges to FPV systems. Several novel FPV system designs are proposed, inspired by high-speed vessel multihulls, including catamaran, trimaran, quadrimaran, and pentamaran configurations, as floating supports for solar panels. Simulations were conducted to determine Response Amplitude Operators (RAOs) under various irregular wave spectrum conditions in a free-floating initial state. The FPV motion problem was solved using linear potential-flow theory with the Boundary Element Method (BEM) with Green-Function approach. Superposition of wave spectral energy and motion RAOs was used to obtain spectral structural responses. Motion in heave, roll, and pitch modes was evaluated across wave spectrum types. Results show that adding hulls reduces the significant amplitude response in all motion modes. In summary, valuable insights into floater designs and the hydrodynamic evaluation of FPV systems are presented.

Tankers are one of the popular modes of transportation associated with liquid cargo. Efficiency with respect to the volume of cargo transported by tankers is an essential consideration in the transportation business process, especially fuel oil, which has become a benchmark for the global economy recently. Various studies have been carried out to optimize cargo space. This study aims to define the factors that influence cargo compartment efficiency to increase the effectiveness in the transportation business. In this study, it is known that the transverse bulkhead arrangement affects the payload capacity, which is related to the criteria in the naval architect principle. The hopper design also influences the optimization of cargo volume, which can provide benefits in terms of payload. Excess cargo volume on existing ships due to hopper design optimization, the future ship design can reduce the length of the cargo compartments that still meet the desired payload. Reducing the length of the cargo hold will undoubtedly provide an opportunity to optimize the scantling analysis for longitudinal and transverse ship structures. This study is expected to be a reference and a more detailed discussion regarding the efficiency of cargo space on tankers in the future.

The objective of this study is to assess the ultimate strength of box girder using equivalent single layer (ESL) approach. Box girders, composed of stiffened panels, are subjected to a four-point bending load for the ultimate strength analysis. The results of ESL were validated using FEM and experiments. Modeling of ESL includes a single plate with the same stiffness as the actual stiffened panel topology, as opposed to traditional FEM modeling and test specimen, where the stiffener is explicitly modeled. For ESL approach, VUGENS subroutine in Abaqus software is used to define the non-linear stiffness properties. Material and geometric non-linearities were considered during simulations. The ESL stiffness matrix was derived from unit cell simulations under six loading conditions. In this case, a unit cell is a periodic structure that represents the entire stiffened panel model. Contact interaction is utilized to simulate the controlled movement of a hollow cylinder contacting a box girder, a precise modeling approach essential for comprehensive analysis. The explicit dynamic analysis is used to allow the large deformation and non-linear material behavior on stiffened panels. The effect of initial imperfection, residual stress, and stiffener slenderness on the ultimate strength was studied. The ultimate strength of a box girder is determined by its maximum bending moment. According to the results, the ESL model achieves results similar to the traditional FEM model and experiment. The accuracy of ESL to FEM in the ultimate strength assessment varies depending on the magnitude of residual stress and initial imperfection applied to the stiffened panel.

Program Sertifikasi Halal Gratis (SEHATI) merupakan program pemerintah pada tahun 2022 yang tertuang dalam Keputusan Kepala BPJPH No.33 Tahun 2022 sebagai program percepatan sertifikasi halal bagi pelaku usaha UMKM. Kegiatan Pengabdian Kepada Masyarakat Abmas ITS ini dilakukan untuk mendorong pertumbuhan ekonomi UMKM sebagai prioritas utama ekonomi Masyarakat, diperkuat peraturan Undang-Undang Nomor 20 Tahun 2021 tentang Jaminan Produk halal yang mewajibkan setiap pelaku usaha untuk wajib memiliki sertifikasi halal dimana Usaha Mikro Kecil dan Menengah (UMKM) memiliki peran krusial dalam peningkatan ekonomi lokal guna pencipataan kesejahteraan masyarakat desa beberapa Kota dan Kabupaten di Jawa Timur Surabaya, Sidoarjo, Nganjuk, Kediri, dan Mojokerto. Proses sertifikasi halal dilakukan dengan menggunakan metode self-declare dan pendampingan kepada pelaku UMKM di Jawa Timur yang dilakukan bertahap dengan total 68 UMKM yang memperoleh fasilitas dalam pendaftaran sertifikasi halal secara gratis dan sebanyak 39 UMKM yang telah memperoleh sertifikat halal. Beberapa produk yang telah mendapatkan sertifikat halal antara lain Martha’s Salad, Sanra Cookies, Pecel Mbok Yem, Es Boba Satu Hati, dan beberapa produk lainnya.

At present, energy transition is a reality in the journey towards achieving net zero emission. Among others, the development of floating solar photovoltaic (FPV) power plants is one of many possible renewable energy technologies that received considerable attention. One of the reasons for that is attributed to land acquisition which can lead to conflicts, whilst the use of sea is more flexible. Therefore, the development of floating solar PV situated at the near shore (later can be moved offshore) is promising particularly in order to withstand the harsh environment. The study aims to demonstrate such an innovative design of a floating structure and two types of hulls (monohull and twin-hull) are considered and focused on the seakeeping performance of the two bodies. BEM approach with Green-Function based on the 3-D diffraction panel method together with the use of the Joint North Sea Wave Project (JONSWAP) wave spectrum is carried out to accomplish the seakeeping characteristic. The final computational simulation results show that the twin-hull model has more advantages than the monohull design. The trend of the RAO pattern, response spectra, and significant response for heave and pitch motion represent only slight differences between the two proposed designs. However, substantial disparity emerges in roll motion, with the difference in response values in prevailing 0o -roll heading standing at 53%, 39%, 27%, and 18% for sea states 1 through 4, respectively. Moreover, in 45o wave heading (quartering sea) it demonstrates a slightly lower disparity compared to the 0o wave heading (following sea) through sea-state 1-4 standing for 50%, 37%, 24% and 16% respectively.

The focus of this study is to demonstrate the applicability of equivalent single layer (ESL) approach for the ultimate strength assessment of stiffened panels under various loading types. In the ESL approach, the stiffened panel is replaced with a single plate, which has the equivalent stiffness of the original panel. Recent investigations have shown that removal of tertiary stiffening elements from the numerical model facilitates time-savings in pre-processing and FE analysis stage, but only limited range of loading types have been considered. Therefore, this paper investigates in more detail the effect of loading type on ESL accuracy. Panels were subjected to combinations of uniaxial (longitudinal and transverse), biaxial and shear load components. Moreover, ESL analysis are conducted both in Abaqus implicit (UGENS subroutine) and explicit (VUGENS subroutine) to provide comparison in terms of numerical efficiency and analysis accuracy between the two numerical schemes.

This study aims to determine the effect of adding variations of fin stabilizers on the hydrodynamic characteristics of the ship design. It compares the hull without modification with the hull modified by a fin stabilizer on a prototype scale. The results of this study is assessed to obtain the best performance of ships with various models to be used in the design of ship realization. The research method is conducted by numerical approach, including simulation of resistance, stability, and seakeeping. The hull design references chosen are the Fast Police Boat and SMIT Patrol Boat with a Length Overall value of 1 m. The fin stabilizer uses hydrofoil type NACA-0015 with an aspect ratio of 0.7. Then the length variations are 3 cm, 4 cm, and 5 cm, with angle variations being 25°, 30°, and 35°. The results showed that adding a fin stabilizer could increase the ship’s stability. The best fin stabilizers variations are fins with a length of 5 cm and an angle of 30° for the prototype design of the Fast Police Boat hull and fins with a length of 5 cm and an angle of 35° for the prototype design of the SMIT Patrol Boat hull.

Ship structure composed of stiffened plates is subjected to a variety of loading conditions during service, which can lead to buckling. As a result of panel buckling, the overall strength of the ship hull girder is reduced, which is what determines the ultimate strength of the hull girder. The ultimate strength analysis can be accomplished with finite element (FE) simulation, but detailed modeling can be time-consuming. Due to these reasons, it is more advantageous and costeffective to replace the three-dimensional (3D) stiffened panel model with a two-dimensional (2D) equivalent single layer (ESL) plate. This shift from 3D to 2D is premised on the accuracy of ESL in representing the various buckling modes of stiffened panels, which are determined by panel topology and boundary conditions. Therefore, an equivalent single layer plate (ESL) that represents a stiffened panel is evaluated in different buckling modes. Considering that ESL is asymmetric in nature, any modification of the stiffened panel's geometry has a significant effect on the buckling modes. In this paper, we are concerned with two modes of buckling: (i) local buckling within the stiffeners of the plate and web, and (ii) local lateraltorsional buckling within the stiffeners. According to the results, ESL is capable of accurately predicting the effect of local buckling in combination of biaxial compression and lateral pressure.

This study aims to analyse the effect of variations in the addition of bilge keel on the value of resistance, ship stability, and seakeeping performances. The research method is carried out by designing and analysing the hull design of the fast patrol boat type with variations in the addition of a bilge keel. Variations made on the bilge keel include length and width. The length variations are considered by applying 4 m, 5 m, and 6 m, while the variations in width include 0.3 m, 0.4 m, and 0.5 m. This study indicates that the nine variations of the bilge keels model with a combination of length and width do not show a significant difference in the resistance value on each ship. Then, for the stability criteria, the bilge keel model IX, with a length of 6 m and a width of 0.5 m, has the best stability value compared to other variations. Meanwhile, the addition of bilge keel in the seakeeping simulation did not show a significant difference. The parameters of this analysis consider the primary needs of fast patrol boats to support the development of shipping technology.