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Rochim Suratman
Guru Besar Teknik Mesin ITB

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KAJI EKSPERIMENTAL DAN NUMERIK TENTAN G FAKTOR KETANGGUHAN RETAK MODUS I DAN II PADA LAMINATE KARBON/EPOXY SERAT TERANYAM Puja, IGN Wiratmaja; Suratman, Rochim; Ramelan, Aditianto; Prasetia, Hariadi Tri
Mesin Vol 15, No 3 (2000)
Publisher : Mesin

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Abstract

This paper presents experimental and numerical analysis on the influence of crack orientations to the fracture toughness of mode I and mode II for woven type carbon/epoxy four ply laminate. The experimental procedure is carried out through off axis tensile test (ASTM D 3039-76) with nine variation of crack orientations i.e. 5°, 10°, 15°, 30°, 45° 65°, 75°, 80°, and 90°. Three rail shear test (ASTM D 4255-83) is utilized for zero degree crack orientation. The stress and strain contours around crack tips are obtained numerically using the finite element method. Numerical and experimental results of the mode I (KI) and mode II (KII) fracture thoughness are presented in graphical form as a function of crack directions. Adopting Wu’s(11) Criteria for unidirectional lamina and Hahn’s[6] Criteria for general anisotropic lamina, a new mixed mode fracture toughness criteria is developed for woven fiber matrix laminate.
PROTOTIPE MESIN UJI LELAH Muchsin, Muchsin; Suratman, Rochim; Sutjiatmo, Bambang; Surdia, Tata
Mesin Vol 3, No 4 (1984)
Publisher : Mesin

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Abstract

Prototipe mesin uji lelah dengan beban tarik bolak-balik dari jenis mekanis direncanakan dan dibuat. Mekanisme beban awal statis terdiri dari baut, puli-mur, tali dan masa pembeban. Spesimen dipegang dengan pasak-pasak yang dapat dikencangkan. Pegas pembeban dipasang seri dengan spesimen. Beban bolak-balik dibangkitkan dengan engkol atur. Batang-batang penghubung, batang transmisi, bersama-sama engkol atur menyusun mekanisme pembebanan.
Sifat Mekanik Packaging Kertas Berbahan Dasar Selulosa Alga Cladophora Mardiyati, Mardiyati; Steven, Steven; Suratman, Rochim; Santosa, Sigit Puji
Mesin Vol 27, No 1 (2018)
Publisher : Mesin

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Abstract

Alga cladophora merupakan salah satu alga yang banyak tumbuh di pesisir pantai Indonesia. Alga cladophora memiliki kandungan selulosa yang cukup tinggi sehingga sangat berpotensi untuk dimanfaatkan sebagai bahan baku material packaging kertas. Tujuan dari penelitian ini adalah mempelajari sifat mekanik kertas yang berbahan dasar selulosa alga cladophora. Pada penelitian ini, selulosa alga cladophora diekstraksi melalui beberapa tahapan proses yang meliputi proses alkalisasi dan proses hidrolisis. Proses alkalisasi dilakukan dengan merefluks alga cladophora didalam larutan NaOH (1%, 5%, 10%, 15% dan 17.5%) pada temperatur 100 ? selama 2 jam. Proses hidrolisis dilakukan dengan merefluks alga cladophora hasil alkalisasi didalam larutan asam sulfat 1 M pada temperatur 100 ? selama 2 jam. Proses pembuatan kertas dilakukan dengan metode solution casting. Kandungan selulosa diukur dengan menggunakan metode Chesson-Datta. Sifat mekanik dari kertas selulosa alga cladophora diukur dengan pengujian tarik. Dari hasil pengukuran kandungan selulosa dapat disimpulkan bahwa selulosa yang diekstrasi dengan menggunakan larutan NaOH 17.5% memiliki tingkat kemurnian yang paling tinggi, yakni 94. 76%. Selulosa yang diekstraksi dengan menggunakan larutan NaOH 17.5% menghasilkan kertas dengan permukaan yang paling halus serta memiliki kekuatan tarik dan kekakuan yang paling tinggi dibandingkan dengan kertas lainnya yang dihasilkan dalam penelitian ini, yakni 57.68 MPa dan 10.12 GPa.
PENGARUH PENAMBAHAN UNSUR Cr DAN Cu TERHADAP KEKUATAN TARIK BESI COR KELABU FC20 Suprihanto, Agus; Satrijo, Djoeli; Suratman, Rochim
ROTASI Volume 9, Nomor 1, Januari 2007
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (315.469 KB) | DOI: 10.14710/rotasi.9.1.17-24

Abstract

The mechanical properties of grey cast iron are influenced by cooling rate, thickness of casting, heat treatment,liquid treatment and alloying. Some aplications of its materials need high strength grey cast iron. To improve itstensile strength usually its added with unsures which known as carbide promoteur ie. Cr and Cu.In these research the effect of Cr and Cu on the mechanicals properties of grey cast irons has been evaluated.Base material FC 20 which alloyed with Cr 0,23 %, 0, 32% and 0,47% and Cu between 0,6% to 0,7% have beentested. The tensile test and metallographyc examinations have been conducted to known of its efects.From tensile test there is an improvement of tensile strength about 20% from 191MPa to 232MPa. However themicrostructure of specimens are same which are pearlitic grey cast irons, with graphite type VII (flake), Adistributions and size of graphite are 3-5.
PENGARUH PENAMBAHAN KROMIUM DAN TEMBAGA TERHADAP KEKUATAN LELAH BESI COR KELABU Suprihanto, Agus; Suratman, Rochim
ROTASI Volume 8, Nomor 1, Januari 2006
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (517.577 KB) | DOI: 10.14710/rotasi.8.1.1-7

Abstract

The mechanical properties of grey cast irons can be modified with alloying elements. Cr and Cu have beenknown as elements that can improve tensile strength of grey cast irons. The improvement of tensile strength can beinfluence of fatigue strength. The goal of this research is to study the effect of alloying Cr and Cu on the fatiguestrength.Four materials of grey cast irons have been conducted to high cycle fatigue testing on the rotating bendingmachine. The first material is grey cast irons without added Cr and Cu, and the other have added. The percentages ofCr have been added are 0,23% wt, 0,32%wt and 0,47%wt and Cu 0,6%wt to 0,7%wt. The metallographyc examinationsand tensile test also have been conducted.The result of this research are the material has the same microstructure. The microstructures of its materials arepearlitic grey cast irons with graphite type VII, distribution A and size of graphite 3-5. The tensile, endurance andfatigue strength of materials, which added Cr and Cu significantly rising, compared with base materials. The tensilestrength rose from 191MPa to 232MPa and the endurance strength raised from 94 MPa to 110MPa. However threemodified materials, which added Cr, and Cu has the same effects.