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Evaluasi Faktor Intensitas Tegangan pada Ujung Retak dengan Lubang Penghambar Rambat Petak Purnowidodo, Anindito
Rekayasa Mesin Vol 1, No 1 (2010)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The evaluation of stress intensity factors in the crack tip interacting with stoping hole of crack growth was conducted by computer simulation, and this was carried out on vareid configuration of stopping hole. The results of the simulation show that the position and zise of stopping hole affect the magnitude of the stress intensity factor. The main cause of the fluctuation of the stress intensity factor is that the stoping hole configuration affects the interaction of stress in the vicinity of crack tip.Keywords : Hole Configuration, Stress Interaction, Stress Intensity Factors
Analisa Kegagalan pada Spindle Mesin Batch Centrifugal Purnowidodo, Anindito; Wahjudi, Ari; Prawira, Riza
Rekayasa Mesin Vol 2, No 1 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Failure analysis was conducted on the failure shaft of batch centrifugal. In the analysis the stress analysis was used to know the stress distribution, and in conjuction with stress analysis the life time of the component can be estimated. In addition, the fractography anlaysis together with mechanical properties test were carried out to understand the mechanism of the failure. With respect to the result of analysis shows that the failure was caused by fatigue crack initated on the surface of shaft due to the inhomogeneus mechanical properties, in this case, the hardness is lower than that on sub surface of the shaft. Besides that, the stress concentration was found take place on the surface of shaft on which the crack was initated. Further, it was known that during machining process, the material of shaft was heated on elevated temperature on the surface to ease the process. The heating reduced the hardness as well as the strength of the material.Keywords : Failure, Fatigue, Crack.
Hubungan Diameter Pasak, Lubang Sambungan Dan Ketebalan Plat Terhadap Distribusi Tegangan Sisa Wahjudi, Ari; Purnowidodo, Anindito; Pambudi, Wijil
Rekayasa Mesin Vol 2, No 3 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The discontinuities on the structures or members are often to be encountered such as, rivet and bolt holes as well as notches. These discontinuities are agents for stress raiser and itcan initiate cracks in the vicinity of holes or in the notch roots. It is well known that most of the fatigue failure is caused by cracks growth initiated from the discontinuities. To reduce possibilitythe initiation of crack in those stress raisers, the compressive residual stress, in general, is imposed to the region in which the stress concentrates. In the present study, using expansionhole technique carried out by aid of computer simulation, the effect of mandrel diameter and thickness of the blank to the residual stress in the vicinity of the hole is investigated. The result shows that the magnitude of the residual stress in the vicinity of the hole varies depending onthe magnitude of the expansion and the thickness of blank. In addition, in the certain distancefrom the hole, the tensile residual stress develops, hence, it may endanger a component because it causes the crack growth rate increase, as consequent, the life time of a componentis shorter.Keyword: mandrell diameter, hole diameter, thickness, residual stress distribution
Pengaruh Kuat Arus Dan Campuran Gas Argon – Co2 Pada Pengelasan Gmaw Terhadap Kekuatan Tarik Dan Impact Pada Baja Karbon Medium Fasa Ganda Suyono, Eko Hendry; Irawan, Yudy Surya; Purnowidodo, Anindito
Rekayasa Mesin Vol 2, No 2 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The function of shielding gas is the most importance in gas metal arch welding, because it protected the oxidation from out side. Argon and CO2 are the shielding gas that often used, choosing the CO2 on mixing shielding gas for some reasons that is readystock , cheap and good penetration.The aim of this research are to know the influence of welding current and mixing shielding gas Argon – CO2 against tensile strength and impact strength on weld of medium carbon steel dual phase. The method of this research as follow AISI 1045 steel forged on temprature 900°C - 950°C then dual phase on 770°C holding tome 90 minutes as dependent variables. The Welding currents are 80A, 100A and 120A , mixing shielding gas , Argon – CO2 : ( 0 – 100%), (100% - 0) and (50% - 50%). Both are as independent variables. Tensile strength and impact strength are as fixed variables.From this research, It can be concluded that welding current and shielding gas have the influenced toward heat input and caused the weld metal fusion or unfusion. This situation influenced toward tensile strength and impact strength.It was prooved that on 80A for the 3rd shielding gas had defect (incomplete fusion and porosity) so the tensile strength and impact strength was very low. On 120A, ArCO2 mixing shielding gas had the highest tensile and impact strength because no defect in it, good fusion. Keywords: Dual phase steel, welding current, mixing shielding gas Ar – CO2, GMAW, tensile strength, impact strength
Pengaruh Temperatur Pelat Landasan Selama Proses Friction Stir Welding Terhadap Kekuatan Tarik Sambungan Las Lembaran HDPE Setiawan, Agus; Irawan, Yudy Surya; Purnowidodo, Anindito
Rekayasa Mesin Vol 2, No 3 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The purpose of this study was to determine the weld ability of HDPE sheets (High Density Polyethylene) through the method of welding FSW (Friction Stir Welding). FSW is a new welding process, where joined of the material occurs in the solid state. Samples were welded with vertical milling CNC machines, while the type of connection is a butt joint. This study used three process parameters, two parameters are combined and one parameter value is constant, the parameters combined are temperature backing plate (30; 70; 110 and 150 oC) and the welding tool rotation speed (2200; 2300 and 2400 rpm), while the parameters with constant value is the welding speed (30 mm / min). In this research experiment conducted observations and analysis of surface textures welded joints, weld surface temperature during the process in front of and behind the welding tools, macro-structure of the welded joints, the maximum tensile strength and fracture tensile test results. From the results of this study was obtained that temperature backing plate during FSW process affects the maximum tensile strength and homogeneity of HDPE sheets welded joints. The maximum tensile strength of welded joints higher is 28.52 MPa or 95.07% of the maximum tensile strength of HDPE material, the maximum ultimate tensile strength values were obtained on the condition temperature backing plate t = 150 oC and the welding tool rotation speed n = 2300 rpm. Heating the material HDPEby backing plate during FSW process insulator properties of the material that is an obstacle inthe process of forming a perfect weld can be resolved.Keyword: temperatur backing plate, friction stir welding, the tensile strength of welded joints,HDPE sheets.
Pengaruh Fraksi Volume Serat Pelepah Gebang (Corypha Utan Lamarck) Terhadap Sifat Mekanik Pada Komposit Bermatrik Epoksi Johanis Abanat, Jufra Daud; Purnowidodo, Anindito; Irawan, Yudy Surya
Rekayasa Mesin Vol 3, No 2 (2012)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Buri Palm trees (Corypha Utan Lamarck) is one of the many types of flora in Indonesia that has not been used optimally. At the leaf midrib of buri palm has fibers that have not been developed from the engineering side. There for in this study used buri palm leaf midrib fiber as an alternative reinforcement material for manufacturing of epoxy composites that can be useful for manufacturing the body of boat, the interior of boat and also for helmets. Thus, this study aims to determine the tensile strength and impact strength of the material in accordance with the desired application. Before being used the fiber from the buri palm leaf midrib should be tested of the tensile strength and the data obtained at 182,24 MPa. Then also tested Alkali treated fiber NaOH 5% and a maximum tensile strength obtained is 212,29 MPa on the sample by treatment for 2 hours. Base on these preliminary data then manufacturing of composite samples using fibers of alkaline NaOH 5% treatment for 2 hours. Variations of fiber volume fraction are from 0%, 10%, 20%, 30%, 40%, 50%, 60% and 70%. The tensile testing sample based on the ASTM D638-3 standard and impact test samples according to ISO 179-1 standard. From the test results is known that the tensile strength of composites increases with increasing fiber volume fraction up to 70% of fiber that is equal to 51,993 MPa. Impact strength also increased up to 70% fiber volume fraction and the maximum impact strength occured is 6,953 J.Keywords: composite, buri fiber, epoxy, volume fraction
Distribusi dan Interaksi Tegangan Sisa antar Lubang Setelah Proses Cold Expansion Hole Wahjudi, Ari; Purnowidodo, Anindito; P, Andika H
Rekayasa Mesin Vol 3, No 3 (2012)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

It is well known that the main cause of a failure of structure is initiated by cracks on a member. A crack may originate easily in a region with high stress concentration. Because in the rivet and the bolt joining method are usual with number of holes, and to reduce the stress concentration, the compressive residual stress is introduced in the region near by the hole. The cold expansion hole technique is used to developed compressive residual on the vicinity of the edge hole. The present study was carried out by the computer simulation based on finite element method to investigate the distribution and interaction residual stress in the region between holes related to the cold expansion hole. The result of the study suggests that the distance between holes influence the state of residual stress and its magnitude. These cause by the deformed material between holes interact each other.Keywords: residual stress distribution, stress interaction, region between holes
Upaya Peningkatan Sifat Mekanik Baja Mild Steel Melalui Perbaikan Kualitas dengan Heat Treatment Annealing dan Holding Time pada Heat Treatment dengan Taguchi Method Rahmadianto, Febi; Purnowidodo, Anindito; Soenoko, Rudy
Rekayasa Mesin Vol 5, No 1 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

The purpose of this study was to determine the ability of the mechanical tensile strength and hardness and microstructure of the steel material Mild Steel. The electrodes used were a new electrode, the electrode was added calium compound is then heated to 100 °C, 100 ° C and heated electrode. Strong currents are used 75 A, 85 A, and 95 A, for a distance of specimen 3 mm, 4 mm and 5 mm. This study used an experimental methodology and the research conducted in the laboratory. The test results showed that the maximum tensile strength is in the condition of the electrode plus a calium compound and heated at 100 ° C, 95 A current and a distance of 5 mm , with Heat Treatment 20 minutes is 278 N/mm2 . Similarly , for the region of weld metal hardness indicates the optimal hardness using electrodes were added and heated calium compounds 100oC , current 95 A and a distance of 5 mm , with Heat Treatment 20 minutes , which is 185 VHN . HAZ hardness to areas with the same test conditions with Weld Metals, hardness value is 371 VHN.Keywords: SMAW, current, Taguchi, optimum treatment.
Perilaku Rambat Retak di Daerah Lubang yang Terekspansi pada Aluminium Alloy Syahrizal, Syahrizal; Purnowidodo, Anindito; Soenoko, Rudy
Rekayasa Mesin Vol 5, No 1 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Mechanism of crack propagation is done by loading the cycle against the perforated metal material will be difficult to avoid, to fatigue crack growth rate can be a way to expand its peg with the hole that normally uses metal balls as an alternative. By using a materials testing machine type cantilever bending eccentric crank, life time of the materials are determined. Research using the method of cold expansion hole in the aluminum alloy metal material to a hole with a diameter of 5 mm in expansion using pin with variation of  5,1 mm,  5,15 mm and  5,2 mm made that crack found on the side of the hole would be difficult to propagate due to residual stress comparison. The result shows that there are residual stresses around the hole which varies depending on the diameter of the pin. In addition, there is growing tensile residual stress within a certain distance of the specimen being tested resulted in a faster growth rate, this causes the material usage time will be shorter.Keywords: cold expansion hole, materials testing machine, aluminumalloy, comparison residual stress, life time.
Perubahan Sifat Mekanis Komposit Hibrid Polyester yang Diperkuat Serat Sabut Kelapa dan Serat Ampas Empulur Sagu Leiwakabessy, Arthur Yanny; Purnowidodo, Anindito; Sugiarto, Sugiarto; Soenoko, Rudy
Rekayasa Mesin Vol 4, No 3 (2013)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Filler composite material with natural fibers is ranging widely known in the manufacturing industry. Environmentally friendly material, able to be recycled, as well as able to destroy it self by nature is a technological demands of today. Coco fiber and pith of sago pulp fiber are natural fibers that derived from the processing of waste coconut and sago palms are abundant in the Moluccas and they have not been used optimally. Both of these materials can be used for the manufacture of composite, using polyester resin as the matrix. The research emphasis to get the maximum value of variation of fiber volume fraction and fiber coir pith of sago waste to the value of bending strength and impact strength, according to the desired application. Research methods Lay Hands Up in the manufacture of hybrid fiber composites with a combination of coconut fiber (SSK): sago pith pulp fibers (SES) with a variation of 10% SSK: SES40%, 20% SSK: SES30%, 30% SSK: SES20%, 40% SSK: SES10%. Dependent variable in the study is the bending strength and impact strength. The result is that an increase in bending strength and impact strength with increasing volume fraction, which is higher than the hybrid fiber coir fiber and coconut fiber pith of sago waste. The highest bending strength of the fiber volume fraction of 30%SSK: SES20%, amounting to 97 354 MPa, and the lowest bending force on the fiber volume fraction of 10% SSK: SES40% of 73 701 MPa, while the highest value of impact strength at SSK fiber volume fraction of 40% :SES10%, at 0178 J/mm², and the lowest value of the impact strength on the fiber volume fraction of 10% SSK : SES40% at 0.053 J/mm².Keywords: Mechanical Properties, composites hybrid, polyester, coconut coir fiber, fiber pulp sago pith.