Delamination or interlaminar fracture often occurs in composite laminate due to several factors such as high interlaminar stress, stress concentration, impact stress as well as imperfections in manufacturing processes. In this study, finite element (FE) simulation of mode I delamination in double cantilever beam (DCB) specimen of carbon fiber/epoxy laminate HTA/6376C is investigated using cohesive zone model (CZM). 3D geometry of DCB specimen is developed in ANSYS Mechanical software and 8-node interface elements with bi-linear formulation are employed to connect the upper and lower parts of DCB. Effect of variation of number of elements on the laminate critical force is particularly examined. The mesh variation includes coarse, fine, and finest mesh. Simulation results show that the finest mesh needs to be employed to produce an accurate assessment of laminate critical force, which is compared with the one obtained from exact solution. This study hence addresses suitable number of elements as a reference to be used for 3D simulation of delamination progress in the composite laminate, which is less explored in existing studies of delamination of composites so far.

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Composite material is a material that has a multi-phase system composed of reinforcing materials and matrix materials. Causes the composite materials to have advantages in various ways such as low density, high mechanical properties, performance comparable to metal, corrosion resistance, and easy to fabricate. In the marine and fisheries industry, composite materials made from fiber reinforcement, especially fiberglass, have proven to be very special and popular in boat construction because they have the advantage of being chemically inert (both applied in general and marine environments), light, strong, easy to print, and price competitiveness. Thus in this study, tensile and impact methods were used to determine the mechanical properties of fiberglass polymer composite materials. Each test is carried out on variations in the amount of fiberglass laminate CSM 300, CSM 450 and WR 600 and variations in weight percentage 99.5% -0.5%, 99% -1%, 98.5% -1, 5%, 98% -2% and 97.5%-2.5% have been used. The results showed that the greater the number of laminates, the greater the impact strength, which was 413,712 MPa, and the more the percentage of hardener, the greater the impact strength, which was 416,487 MPa. The results showed that the more laminate the tensile strength increased, which was 87.054 MPa, and the more the percentage of hardener, the lower the tensile strength, which was 73.921 MPa.

Pada industri perkapalan maupun dirgantara material aluminium banyak diaplikasikan sebagai bahan baku pembuatan kapal maupun pesawat. Aluminium dipilih karena memiliki kekuatan tarik relatif tinggi, sifat mampu bentuk yang baik, tahan terhadap korosi dan logam ringan. Penelitian ini bertujuan untuk mengembangkan teknik penyambungan logam pada aluminium. Pengelasan merupakan metode penyambungan yang sudah dilakukan sejak lama. Metode pengelasan semakin berkembang sesuai kebutuhan industri. Pengelasan FSW (Friction Stir Welding) salah satu yang dikembangkan oleh TWI. Penelitian ini bertujuan untuk mengetahui kekuatan tarik pengelasan Friction Stir Welding dengan varisi laju pengelasan. Proses pengelasan menggunakan putaran tool 2000 RPM, dengan laju pengelasan 50 mm/min,, 100 mm/min, dan 200 mm/min. Proses FSW dilakukan pada sambungan tumpul (butt joint) Hasil penelitian menunjukan bahwa pada laju pengelasan 50mm/min memiliki kekuatan tarik paling baikk. Kekuatan tarik menurun seiring meningkatnya kecepatan pengelasan.

Microstructural analysis has been performed on magnesium alloy electrodes, the material used for saltwater lantern batteries. This research aims to obtain detailed and accurate information needed to support the analysis of magnesium alloy corrosion resistance caused by the electrolysis process using various analytical methods in SEM(Scanning Electron Microscopy). It is a tool that uses an electron beam to display the surface structure and composition of a test material. The test carried out on this magnesium alloy electrode is to crush the electrode into a fine powder. Then the powder is put into a container for SEM-EDS testing. Magnifications start from 1,000xuntil 15,000x. The results showed that the greater the magnification on the microscope, the more it was seen that the lumps looked brittle. Then on the surface of the magnesium alloy electrodes, 58.00 wt% magnesium material is contained.