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Studi Ukuran Grafit Besi Cor Kelabu Terhadap Laju Keausan Pada Produk Blok Rem Metalik Kereta Api Lilik Dwi Setyana
Jurnal Material Teknologi Proses: Warta Kemajuan Bidang Material Teknik Teknologi Proses Vol 1, No 1 (2015)
Publisher : Departemen Teknik Mesin, Sekolah Vokasi, Universitas Gadjah Mada.

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (288.339 KB) | DOI: 10.22146/jmtp.v1i1.12258

Abstract

Blok rem kereta api yang diproduksi di Ceper Klaten Jawa Tengah menggunakan besi cor kelabu.  Permasalahan yang sering dijumpai adalah ketahanan terhadap gesekan yang kurang baik sehingga mempengaruhi lama waktu penggunaanya, namun jika kekerasan blok rem tersebut terlalu tinggi maka roda kereta api yang akan lebih cepat aus.Penelitian  dilakukan dengan mengidentifikasi 20 blok rem kereta api yang dinyatakan lolos uji dan tidak lolos uji dari tingkat kekerasannya, kemudian diamati struktur mikronya. Kemudian diambil 5 spesimen dengan besar grafit yang berbeda. Pengujian yang dilakukan meliputi uji kekerasan, uji keausan dan pengamatan struktur mikro.Hasil penelitian menunjukkan bahwa kekerasan tertinggi (207 BHN) terjadi pada spesimen 1 dengan ukuran grafit terkecil sedangkan kekerasan terendah (113 BHN) terjadi pada spesimen 5 dengan ukuran grafit terbesar. Laju keausan terendah (2,1.10-4 mm3/kg.m) terjadi pada spesimen 5 dengan ukuran grafit terbesar (laju keausan turun hingga 76% dari spesimen 1). Sedangkan berdasar pengamatan struktur mikro, ukuran grafit dengan panjang rata-rata  40 hingga 70 µm dan lebar rata-rata 5 µm mempunyai nilai kekerasan standar untuk blok rem (175 hingga 197 BHN).
Integritas Struktur Alas Prostetik Pergelangan Kaki dengan Bahan Baja dan Aluminium Handoko; Lilik Dwi Setyana; Budi Basuki; Setyawan Bekti Wibowo; Bambang Hari Priyambodo; Yani Kurniawan; Rizky Kurniawan
Jurnal Engine: Energi, Manufaktur, dan Material Vol. 9 No. 2 (2025)
Publisher : Universitas Proklamasi 45

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30588/jeemm.v9i2.2465

Abstract

Leg prosthetics support the mobility of people with disabilities. Designing economical leg prosthetics is a major challenge for increasing accessibility for disabled people because the majority of them are from low income economy. Technically, the challenge is to make a cheap buat light weight prosthetics. Low cost metal raw material of prosthetics are often inversely proportional to the weight of components. One of the cheap materials, i.e. steel has a specific gravity 2.9 times higher than aluminum, which is lightweight but twice as expensive. This study examines the structural integrity of ankle prosthetic base components made of steel and aluminum when subjected to dynamic loads of the human body in a single step, using finite element method numerical computations. The goal is to determine whether the type of cheap material will be reliable in bearing the load. The computational results show that inexpensive materials such as mild steel and aluminum 6061 are able to support the mechanical structure of ankle prosthetic model to remain rigid while handling dynamic loads. The working stresses of both materials are still within safe limits, able to bear the load, even when multiplied by safety factor, the stresses are still below the yield stress value of each material. Aluminum 6061 is recommended for the production of lightweight versions of prosthetic models due to its maximum deflection that is really small as low as 4.41 x 10-3 mm, while mild steel is for the low-cost versions. Validation of the computational results was carried out using comparative literature data. Contact pressure value of 3 MPa from this research is in accordance with literature.