Pengaruh Fraksi Massa Sabut Kelapa Terhadap Kekuatan Mekanik Material Komposit Sebagai Filler Helm Safety Sesuai Standar Sni Dengan Metode Hand Lay Up

The Effect Of Coconut Husk Mass Fraction On The Mechanical Strength Of Composite Materials Used As Filler In Safety Helmets In Accordance With Sni Standards Using The Hand Lay Up Method

Tingginya angka kecelakaan kerja di Indonesia menunjukkan pentingnya penggunaan alat pelindung diri, khususnya helm safety, yang mampu memberikan perlindungan terhadap risiko benturan pada kepala. Di sisi lain, pemanfaatan serat alam sebagai penguat komposit dapat menjadi alternatif material yang lebih ekonomis dan ramah lingkungan, salah satunya serat sabut kelapa yang tersedia melimpah di Indonesia. Penelitian ini bertujuan untuk mengetahui pengaruh variasi fraksi massa serat sabut kelapa terhadap kekuatan impak dan kekuatan bending material komposit serta mengetahui kemampuan prototipe helm safety dengan komposisi terbaik dalam menerima benturan berdasarkan SNI ISO 3873:2012. Penelitian menggunakan metode eksperimen dengan serat sabut kelapa sebagai penguat dan resin poliester sebagai matriks yang difabrikasi menggunakan metode hand lay up dengan variasi fraksi massa serat 30%, 40%, 50%, dan 60%. Pengujian impak dilakukan berdasarkan ASTM D5942 dan pengujian bending berdasarkan ASTM D790. Fraksi massa dengan sifat mekanik terbaik selanjutnya digunakan untuk membuat prototipe helm safety yang diuji redam kejut menggunakan energi benturan sebesar 50 J. Hasil penelitian menunjukkan bahwa fraksi massa 40% menghasilkan sifat mekanik terbaik dengan energi serap sebesar 11,428 J, kekuatan impak 0,115 J/mm², beban maksimum bending 354,93 N, dan kekuatan bending 134,14 MPa. Pada fraksi massa 50% dan 60%, sifat mekanik mengalami penurunan karena berkurangnya kemampuan matriks dalam membasahi dan mengikat serat secara optimal. Prototipe helm safety dengan fraksi massa serat 40% tidak mengalami kegagalan struktur setelah menerima benturan sebesar 50 J dan hanya mengalami matrix cracking. Berdasarkan hasil tersebut, dapat disimpulkan bahwa fraksi massa serat 40% merupakan komposisi optimum dalam penelitian ini. Hasil penelitian menunjukkan bahwa komposit serat sabut kelapa berpotensi dikembangkan sebagai material alternatif cangkang helm safety berbasis serat alam, dengan penelitian lanjutan diperlukan untuk mengoptimalkan desain dan memenuhi keseluruhan persyaratan helm safety.

The high number of occupational accidents in Indonesia highlights the importance of using personal protective equipment, particularly safety helmets, to provide protection against the risk of head impacts. On the other hand, the utilization of natural fibers as composite reinforcement offers an alternative material that is more economical and environmentally friendly, including coconut coir fiber, which is abundantly available in Indonesia. This study aims to determine the effect of coconut coir fiber mass fraction variations on the impact strength and bending strength of composite materials and to evaluate the ability of a safety helmet prototype with the optimum composition to withstand impact based on SNI ISO 3873:2012. This study employed an experimental method using coconut coir fiber as reinforcement and polyester resin as the matrix, fabricated using the hand lay-up method with fiber mass fractions of 30%, 40%, 50%, and 60%. Impact testing was conducted according to ASTM D5942, while bending testing was performed according to ASTM D790. The mass fraction exhibiting the best mechanical properties was subsequently used to fabricate a safety helmet prototype, which was subjected to an impact absorption test with an impact energy of 50 J. The results showed that the 40% mass fraction produced the best mechanical properties, with an absorbed energy of 11.428 J, impact strength of 0.115 J/mm², maximum bending load of 354.93 N, and bending strength of 134.14 MPa. At mass fractions of 50% and 60%, the mechanical properties decreased due to the reduced ability of the matrix to adequately wet and bond the fibers. The safety helmet prototype with a 40% fiber mass fraction did not experience structural failure after receiving a 50 J impact and exhibited only matrix cracking. Therefore, the 40% fiber mass fraction was concluded to be the optimum composition in this study. These findings indicate that coconut coir fiber composites have the potential to be developed as an alternative natural fiber-based material for safety helmet shells, although further research is required to optimize the design and satisfy the overall safety helmet requirements.