Running-in as an Engineering Optimization

Running-in is a process which can be found in daily lives. This phenomenon occurs after the start of the contact between fresh solid surfaces, resulting in changes in the surface topography, friction and wear. Before the contacting engineering solid surfaces reach a steady-state operation situation this running-n enhances the contact performance. Running-in is very complex and is a vast problem area. A lot of variable occurs in the running-in process, physically, mechanically or chemically. These transient phenomena should be optimized so that it is beneficial. In this paper the global analysis of running-in in term of engineering optimization is presented. Literature that reports of what have been published about knowledge and ideas, on the running-in topic by accredited scholars and researchers, are reviewed. The running-in model which can predict the real engineering surfaces in its operation is proposed

Deformation due to contact between a rough surface and a smooth ball

Theoretical and experimental results are presented to evaluate the deformation behavior of the contact between a real rough flat surface and a smooth ball. There are three deformation responses: plastic deformation of the asperities only, plastic deformation of the bulk only and combined plastic deformation of both the asperities and the bulk. The effects of the surface roughness and the Hertzian contact parameters on the effective contact pressure are presented. The experimental results confirmed the theoretical prediction very well. For a given Hertzian contact situation the surface roughness plays an important role in controlling the deformation behavior of the contacting surfaces. A criterion is presented to predict the deformation behavior of contacting engineering surfaces

Perancangan Dan Pembuatan Alat Keramas Portable Untuk Pasien Rumah Sakit Dengan Metode Morfologi

Comfort and personal treatment is one of a basic human need in healthy or in being treated condition.The aim of this paper is to develop a portable shampooing equipment for hospital patients. In product design, the variation of product involves specific parameters of the existing product in order to create a new product design. There are several methods of product design process for determining the best product. Product design method used in this study is morphological method.This method contains a list of all possible solutions to the non-quantitatively multi-dimensional problems. Several product design concepts are presented in this study and the process of selecting the best product concept is also demonstrated. A concept of portable shampooing product equipment that can be usedto treat hospital patients has been successfully developed and the prototype of such concept has been manufactured

Analisa Karakteristik Minyak Pelumas Jenis 15w-40 Produk Dalam Negeri Menggunakan Tribometer Pin-on-ring

Kemampuan mesin dalam mempertahankan performa terhadap penggunaan berulang merupakansalah satu hal penting dalam perancangan permesinan. Gesekan antar komponen mesin yang salingkontak menjadi fenomena yang sering menyebabkan penurunan performa dari mesin. Hal itudisebabkan oleh terjadinya aus pada komponen yang saling kontak tersebut. Salah satu cara yangefektif untuk mengurangi keausan komponen adalah dengan memberikan pelumas. Minyakpelumas mempunyai karakteristik yang berbeda-beda disesuaikan dengan penggunaan dan kondisilingkungannya. Kurva Stribeck merupakan kurva hubungan antara koefisien gesekan danlubrication number yang dapat digunakan untuk mengetahui karakteristik dari minyak pelumas.Pelumas jenis 15W-40 merupakan salah satu jenis pelumas yang cocok digunakan di iklim tropisseperti di Indonesia. Penelitian ini akan difokuskan pada analisa kurva Stribeck pelumas jenis15W-40 produk dalam negeri menggunakan tribometer pin-on-ring. Pengujian dilakukan darikecepatan 2-250 rpm dengan temperatur dikondisikan 40oC, beban yang diberikan 100 N, danviskositas yang digunakan 0,09924 Pa.s. Penelitian dilakukan selama kondisi running-in, yaitu darikondisi awal sampai kondisi tunak (steady state). Hasil yang diperoleh menunjukkan bahwakondisi running-in terjadi sampai pada pengujian keenam. Semakin besar kecepatan yangdiberikan, maka koefisien gesek yang dihasilkan semakin kecil. Regime yang terbentuk dalamkurva Stribeck pada penelitian ini adalah boundary lubrication dan mixed lubrication

Running-in of rolling contacts

This thesis deals with running-in of the pure rolling contact situation operating in the boundary lubrication regime, so that normal plastic deformation due to the contact between asperities is the main aspect. The change of the surface topography during the running-in process and the run-in surfaces are predicted locally. The main theme concerns the elastic-plastic asperity contact model. An asperity micro-contact model was considered due to its analytical nature and a well-ploughed study. A new single elliptic elastic-plastic asperity contact model has been proposed and demonstrated as the best prediction to the experimental results among the other models. Plastic deformation appears when the applied load is removed; therefore, the developed asperity contact model was extended to the unloading case

Friction Analysis on Scratch Deformation Modes of Visco-Elastic-Plastic Materials

Understanding of abrasion resistance and associated surfaces deformation mechanisms is of primary importance in materials engineering and design. Instrumented scratch testing has proven to be a useful tool for characterizing the abrasion resistance of materials. Using a conical indenter in a scratch test may result in different deformation modes, like as elastic deformation, ironing, ductile ploughing and cutting. This paper presents the friction analysis of some deformation modes of visco-elastic-plastic behaving polymer materials, especially PEEK (poly etheretherketone). In general, it is accepted that the friction consist of an adhesion and a deformation component, which can be assumed to be independent to each others. During a scratch test, the friction coefficient is influenced by some parameters, such as the sharpness of indenter, the deformation modes and the degree of elastic recovery. Results show that the adhesion component strongly influences the friction in the elastic and ironing deformation mode (scratching with a blunt cone), friction for the cutting deformation mode (scratching with a sharp cone) is dominantly influenced by the deformation component. From the analysis, it can be concluded that the adhesion friction model is suitable for ironing - elastic deformation mode and the deformation friction model with elastic recovery is good for cutting mode. Moreover, the ductile ploughing mode is combination of the adhesion and plastic deformation friction model

Friction Reduction in Lubricated-MEMS with Complex Slip Surface Pattern

AbstractMany types of micro-electro-mechanical-system (MEMS) based products are currently employed in a variety of applications. However, high friction in these systems is a problem which limits the development of MEMS devices in which sliding contacts are involved. The aim of this research is to evaluate the effect of boundary slip on the hydrodynamic friction in a low load lubricated MEMS, in particular when boundary slip takes places in the certain region of the lubricated sliding contact, i.e. complex slip surface pattern. The effectiveness of the boundary slip in reducing friction is highlighted. The results indicate that the deterministic complex slip pattern has a beneficial effect on decreasing friction

Karakteristik Aisi 304 sebagai Material Friction Welding

Stainless steel tipe austenitic dipilih sebagai material untuk sebuah produk karena sifat tahan korosi, non magnetic dan weldability yang baik. Beberapa peneliti menggunakan AISI 304 sebagai material riset yang disambung dengan material lain seperti alumunium dan copper dengan metode friction welding. Pengelasan gesek menggunakan parameter seperti friction time, friction pressure, upset time, upset pressure dan putaran spindle. Untuk memudahkan analisa struktur mikro, Sathiya membagi spesimen menjadi 3 region, sedangkan Ozdemir membagi zona menjadi fully plastic deformed zone (FPDZ), partial deformed zone (PDZ) dan deformed zone (DZ). Nilai kekerasan daerah sekitar sambungan AISI 304 menurut Paventhan adalah 490HV, Mumin Sahin nilai Hardness 225-250HV. Nilai kekerasan AISI 304-AISI 202 yang disambung dengan friction time 30 dan 40 detik mempunya nilai kekerasan pada AISI 304 kekerasan HAZ sebesar 686 HV dan 567 HV. Nilai kekerasan yang berbeda didipengaruhi oleh friction time serta prosentase Cr didalam komposisi kimia materia

Sliding Wear Modeling of Artificial Rough Surfaces

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.

Surface Hardening Characterization Of Transmission Gears

This paper is presented to compare the transmission gear products from SME (UKM gear) and national scale manufacturer (OEM gear) especially on the surface hardening characterization. Both gears were heat treated with different methods. The gear product of SME was heat treated by pack carburizing and quenching whereas the OEM gear was predicted to be heat treated using induction heating with high frequency. The surface hardening characterization was conducted by investigating the hardening thickness, the hardness number and the microstructure observation on the gear surfaces. The result of the hardening thickness investigation reveals a distinction on the depth of hardening penetration. The heat treatment using long interval pack carburizing of UKM gear produces a deeper penetration and the higher hardness number on the gear surface whereas the OEM gear has a thin hardness penetration and lower hardness number. The microstructure of the both gears depicts the different types of phase. The SME gear shows the present of the carbon infiltration on the martensitic phase structure boundary whereas the OEM gear exhibits lower bainite phase on the gear surface. With this condition the OEM gear is predicted to behave a better contact stress distribution during operation