Jamari Jamari
Jurusan Teknik Mesin, Fakultas Teknik, Universitas Diponegoro Jl. Prof. Sudharto, Kampus UNDIP Tembalang, Semarang 50275

Published : 44 Documents
Articles

ANALISA KONTAK STATIS PERMUKAAN KASAR BERBASIS ELEMEN HINGGA Jamari, Jamari
ROTASI VOLUME 13, NOMOR 2, APRIL 2011
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (447.431 KB) | DOI: 10.14710/rotasi.13.2.13-17

Abstract

Teori kontak permukaan kasar telah lama dikembangkan oleh banyak peneliti. Pengembangan kontak elastis, elastoplastis dan plastis telah banyak dilakukan. Umumnya pemodelan permukaan kasar diwakilkan oleh asperiti. Asperiti sering diwakilkan dengan bentuk sederhana setengah bola (hemisphere). Untuk memodelkan permukaan kasar yang sesungguhnya, seperti hasil pengukuran, merupakan sebuah usaha yang tidak mudah. Paper ini bertujuan untuk memodelkan kontak permukaan kasar sesungguhnya akibat beban statis menggunakan metode elemen hingga. Pemodelan permukaan kasar sesungguhnya dilakukan dengan cara memanfaatkan software CAD. Geometri permukaan kasar hasil pengukuran masih berupa titik-titik dengan ketinggian tertentu. Software CAD mengubah geometri permukaan kasar ke dalam bentuk geometri solid tiga dimensi. Model permukaan kasar kemudian digunakan untuk analisa kontak. Beberapa parameter utama kontak seperti luas permukaan kontak, deformasi, dan lain-lain ditampilkan pada kontak antar permukaan kasar dengan sebuah bola.
Sliding Wear Modeling of Artificial Rough Surfaces Syafa’at, Imam; Setiyana, Budi; Muchammad, Muchammad; Jamari, Jamari
International Journal of Science and Engineering (IJSE) Vol 4, No 1 (2013)
Publisher : Chemical Engineering Diponegoro University

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Abstract

Surface roughness plays an important role in machine design. In the micro-scale when two engineering surfaces are brought into contact, the real contact area occurs at isolated point of asperity. Wear is one of some effects of contacting surfaces. This paper presents a modeling of sliding wear at asperity level on the artificial rough surfaces. The surface roughness is represented by spherical asperities at the hemispherical pin that is developed from the existing model. The wear model is based on the simple analytical solution. The combination of Archard’s wear equation and finite element simulation is performed to predict the wear. Results show that the increasing of sliding distance give the increasing of wear depth, wear scar diameter and wear volume of the asperity. Wear at the center of the contacting rough surface is higher than the its surrounding. [Keywords: Rough Surface; Sliding Wea; Wear Scar Diameter; Wear Volume]
ANALISA KONTAK ANTAR HEMISPHERES PADA DAERAH ELASTIS-PLASTIS MENGGUNAKAN METODE ELEMEN HINGGA Yusra, Arda; Haryanto, Ismoyo; Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 10, Nomor 2, April 2008
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

Analisa kontak antar hemispheres (bentuyk setengah bola) pada daerah elastis-plastis menggunakan metode elemen hingga akan dipresentasikan pada paper ini. Permukaan kontak yang dianalisa diasumsikan sebagai kontak tanpa gesekan (frictionless contact). Hubungan antara beban kontak, tekanan kontak rata-rata dan luas permukaan kontak rata-rata adalah beberapa parameter yang akan ditunjukkan pada analisa kontak elastis-plastis antar hemispheres tersebut. Hasil dari analisa ini akan dibandingkan dengan teori kontak elastis-plastis dari model-model yang telah dipublikasikan pada jurnal-jurnal internasional.
MEASUREMENT OF THE SURFACE TOPOGRAPHY CHANGE ON A BOUNDARY LUBRICATED RECIPROCATING SLIDING CONTACT Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 10, Nomor 2, April 2008
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

This paper presents experiments to study the change of the surface topography on a boundary lubricated reciprocating sliding contact system. A  Micromap 512 optical profilometer is employed for measuring surface characteristics. The change of the surface topography before and after the experiment is determined in detail and accurate (microscopically) by the Matching and Stitching method.  Plot of the profile of the surface roughness for a certain number of running-in cycles were presented in a figure for before, after and difference, so that analysis of the surface topography change can be accurately performed
WEAR PREDICTION USING GIWM (GLOBAL INCREMENTAL WEAR MODEL) METHOD Jamari, Jamari
ROTASI Volume 11, Nomor 4, Oktober 2009
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (320.015 KB) | DOI: 10.14710/rotasi.11.4.1-4

Abstract

Wear is very important parameter in an engineering design. A model for predicting the wear behaviour is presented in this paper. The model, which is called global incremental wear model (GIWM), is build upon an iterative procedure. This study considers the pin-on-disc sliding contact system. The model for computing wear on pin is based on the idea of successively computing the contact radius and thus the contact area due to the flattening of the spherical tipped pin. In order to verify the developed model, the results are plotted together with the published results. There are two publisher results, numerically and experimentally. Results show that the developed GIWM model predicts the wear behavior very well.
AN ELASTIC-PLASTIC MICROCONTACT MODEL OF ASPERITIES Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 8, Nomor 2, April 2006
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

In this paper a theoretical model for the elastic-plastic microcontact model of asperities is presemted. Relationof the contact parameters, such as the mean contact pressure, the contact area and the contact load as a function of thecontact interference are modeled in the elastic, elastic-plastic and fully plastic contact regime. The model is verified bythe experimental results and is compared with published theoretical models. Very good agreement between the presentmodel and the experimental results are found compared to the prediction of the other contact models.
AN ELLIPTIC ELASTIC-PLASTIC ASPERITY MICRO-CONTACT MODEL Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 8, Nomor 3, Juli 2006
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

A theoretical model for the elastic-plastic contact of ellipsoid bodies is presented in this paper. Contactparameters, such as the mean contact pressure, the contact area and the contact load as a function of the contactinterference are formulated and modeled in the three different contact regimes: elastic, elastic-plastic and fully plastic.The model introduces a new simple method to analyze the complexity of the elliptical integral by an accurateapproximation so that the calculation can be executed very fast.
MATCHING AND STITCHING FOR SURFACE IDENTIFICATION Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 8, Nomor 4, Oktober 2006
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

An algorithm to determine changes in surface topography on asperity level has been developed in this paper. The software tool stitches small but detailed images together to create one large image. If such an image is made before and after an experiment, their difference shows a direct 3D view of the changes in micro-geometry, rather than a change in surface parameters such as RMS or CLA roughness. The algorithm is described in detail and demonstrated by appling to real rough surfaces.
ANALISA KONTAK ELASTIS ANTAR HEMISPHERES MENGGUNAKAN METODE ELEMEN HINGGA Yusra, Arda; Haryanto, Ismoyo; Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 10, Nomor 1, Januari 2008
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

Pada paper ini akan dipresentasikan analisa kontak antar hemispheres (bentuk setengah bola) pada daerah elastis menggunakan metode elemen hingga. Analisa dilakukan dengan mengasumsikan permukaan kontak tanpa gesekan (frictionless contact). Hubungan antara beban kontak, tekanan kontak rata-rata dan luas permukaan kontak rata-rata adalah beberapa parameter yang akan ditunjukkan pada analisa kontak elastic antar hemispheres. Hasil dari analisa ini akan dibandingkan dengan teori kontak elastic Hertz atau yang lebih dikenal dengan kontak Hertz (Hertzian contact) yang menganalisa kontak secara analitik.
POWER SPECTRAL DENSITY ANALYSIS OF STEEL SURFACE TOPOGRAPHY CHANGE ON A BOUNDARY LUBRICATED RECIPROCATING SLIDING CONTACT Jamari, Jamari
ROTASI "JURNAL TEKNIK MESIN" Volume 10, Nomor 1, Januari 2008
Publisher : ROTASI "JURNAL TEKNIK MESIN"

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Abstract

Study the change of the surface topography using spectral density analysis was done by performing experiments on ball-on-plate steel under boundary lubricated reciprocating sliding contact. Measurement of the surface topography was executed by an optical profilometer: Micromap 512. Matching and Stitching computer code method was employed in order to get more detailed information about the surfaces before and after the experiment. The profile evolutions of the surface for a certain number of running cycles were presented on the PSD (Power Spectral Density) and spatial frequency form. In the analysis, results show that the surface changes more in the running direction than in the traverse direction.