Telah banyak diteliti metode stophole untuk menghambat pertumbuhan retak pada bahan logam, namun belum ada penelitian tentang metode stophole ini untuk menghambat retak pada bahan komposit. Penelitian ini mengguankan komposit epoxy dan serat kaca dengan katalis epoxy hardener (polyaminoamide), arah serat yang digunakan adalah serat acak, lapisan komposit terdiri dari 4 lapis,  dengan komposisi 30% serat, 69.7% resin, dan 0,3% katalis digunakan. Spesimen uji menggunakan CTS sesuai standar pengujian ASTM E 647 dengan retak awal sepanjang 20 mm dengan variasi diameter lubang stophole 2mm, 3mm, 4mm, dan 5mm serta jarak lubang dan retak 5mm, 10mm, dan 15mm. Hasilnya didapatkan jarak lubang yang paling optimum yang menyebabkan tegangan tarik tertinggi terletak pada jarak 10mm dari ujung retak, dan diameter optimumnya adalah 5mm dengan kekuatan tarik maksimum 22.74 Mpa, lebih tinggi daripada kekuatan tarik maksimum tanpa stophole (13.3 Mpa). Sehingga dapat disimpulkan adanya variasi stophole mempengaruhi tegangan tarik maksimum komposit epoxi serat gelas, karena pada ujung retak dan sisi lubang terdapat pemusatan tegangan, dan juga perbedaan mode patahan.

This research proposes a new idea of the preventive maintenance method of the lathe by analyzing the vibration on the fixed gear gearbox of the Maximat lathe. From the results of the vibrations that occur, checks are carried out on the lubricating oil, disability of the existing gears and bearings, and then repairing the gear and bearing and replacing the lubricating oil. To find out the magnitude of vibration that occurs in this maximat lathe, rotation variations are carried out by 1000 (rpm), 1500 (rpm) and 2000 (rpm). The highest average amplitude value at 1000 RPM engine speed is on the Bu04 machine with a value of 0.034 mm / s RMS while the lowest value is obtained on the Bu03 lathe with a value of 0.029 mm / s RMS. At 1500 RPM engine speed, the highest average amplitude value is obtained on the Bu03 lathe with a value of 0.045 mm / s RMS. On the Bu02 lathe with a value of 0.032 mm / s RMS. At 2000 RPM engine speed, the highest average value of amplitude was obtained in the Bu03 lathe with a value of 0.069 mm / s RMS. While the lowest value obtained on the Bu02 lathe with a value of 0.050 mm / s RMS. The lower the vibration of the lathe, the more optimal the results of turning. There is an influence between the speed of the engine against the vibrations that occur. Lathe with a high amplitude level indicates that there are components that need attention

The strength of material is a parameter to show mechanical material characteristic, which is determined based on the endurance of supporting external force. In materials science, it is know as the various meanings of strength based on how far external force causes the impact on the material. Resin material is a polymer produced by chemical industry and is used in various applications, among other are packing, textile (example: rope, thermal clothing, and carpet), while banana stalk which contain water has not been used in engineering. The mixture of banana stalk fiber with catalyst resin is called composite. Composite is a solid material produced by the combination between two or more diffrent materials to obtain better characteristic which cannot be obtained from every component.Testing method of composite is done by being pressed with long , thick, wide size based on the standard. The up and down part of the material is clamped and then the testing instrument pulls the tested object so that can show maximum pulling power of 10.2 x 105 kg/m2 with a speed of 100 mm/minute.