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IGN Wiratmaja Puja
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Mechanical Engineering

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ANALISIS MEDAN ELASTIS DI DALAM SETENGAH RUANG ISOTROPI MELINTAN G AKIBAT BEBAN NORMAL DI PERMUKAANNYA IGN Wiratmaja Puja
Mesin Vol. 13 No. 1 (1998)
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This paper evaluate the elastic field that induced by a uniform pressure applied over a circular area on the surface of an elastic half space. The half space is transversely isotropic, where the planes of isotropy are parallel to the surface. A potential function method is adopted where the elastic field is written in terms of three harmonic functions. The known point force Green functions are used to find the solution for uniform normal load over the area by quadrature. The elastic displacement and stress field are evaluated in term of closed form expressions containing complete elliptic integrals of the first, second and third kinds. Following limiting procedure allows the isotropic solution to be obtained. It is shown that the present results agree with the previous published solutions but the new solutions could be put in a more convenient form. Special consideration is also given to derive the limiting form of the stress field on the surface.
PENGARUH ARAH SERAT DAN SUSUNAN LAPISAN TERHADAP FAKTOR KONSENTRASI TEGANGAN PADA KOMPOSIT LAMINATE CARBONIEPOXY AS4/3501-6 BERLUBAN G LIN GKARAN DAN ELLIPS IGN Wiratmaja Puja; Satryo Soemantri B; Budi Riyanto
Mesin Vol. 13 No. 2 (1998)
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In recent years, fiber-matrix composite laminates have been widely used in mechanical structures. Due to functional design requirements, the laminates may contain holes that could cause stress concentration. Unlike isotropic plate, where the stress concentration depend upon geometric parameter and loading conditions, stress concentration factor of fiber-matrix composite is also depend on the anisotropic properties such as fiber direction and angle ply. This paper present intensive studies of the influence of the fiber direction and angle ply to the stress concentration factors for composite laminate containing circular and elliptical hole under uniaxial loading. The stress concentration factor curves are presented for various angle ply, fiber direction, and geometric parameter. These curves could be used by designer to obtain the optimum design of laminate structure containing hole.
PENGARUH ARAH SERAT TERHADAP FAKTOR INTENSITAS TEGANGAN PADA UNIDIRECTIONAL LAMINA YANG MENGANDUNG CENTER CRACK IGN Wiratmaja Puja; Yedi R Supriyadi
Mesin Vol. 15 No. 2 (2000)
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This paper presents the stress intensity factor (SIF) analysis for unidirectional fiber-matrix lamina containing center crack under uniaxial loading. Several variables are considered on the influence to the stress intensification factor i.e. fiber direction,θ, crack dimension parameter, 2a/L, fiber and matrix volume fraction, Vf, Vm, fiber and matrix stiffness ration, Ef/Em, and lamina thickness. The stress-strain equations for the lamina are derived using micromechanic approach. The governing equations are solved numerically using the finite element method with triangular type element. The element stifiness matrix is obtained using the polynomial shape functions. The software to calculate stress-strain in the lamina containing center crack is developed. Case studies jor numerical purposes consider the carbon-epoagz lamina with carbon type P-100. Numerical results for carbon epoxy lamina are presented in graphical form of SIF as a fimction of the fiber direction, fiber matrix stifihess ratio and volume ratio, and crack geometry.
KAJI EKSPERIMENTAL DAN NUMERIK TENTAN G FAKTOR KETANGGUHAN RETAK MODUS I DAN II PADA LAMINATE KARBON/EPOXY SERAT TERANYAM IGN Wiratmaja Puja; Rochim Suratman; Aditianto Ramelan; Hariadi Tri Prasetia
Mesin Vol. 15 No. 3 (2000)
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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.
ANALISIS KEGAGALAN DRUM REM PRODUKSI UKM UNTUK TRUK/BUS DENGAN DAYA MESIN 190 HP IGN Wiratmaja Puja; Rochim Suratman; Agus Suprihanto; Reza Reza; Henry Ako
Mesin Vol. 17 No. 2 (2002)
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Indonesian small and medium industries (UKM) have the ability to produce relatively cheap truck/bus brake drums, but the quality is needed to be improved. The drums usually fail in form of cracks or fractures before the design life is reached. This paper presents failure identification of the UKM's brake drums that is including material aspects, operational loading, and stress analysis. The mechanical and physical properties of the materials are studied by conducting tensile test, hardness test, chemical composition, and metallography. Fractography is also conducted to study the type and process of the failures. The brake loads are analyzed for various operational conditions such as straight, curved, and downhill path, with various value of decceleration. Stress analysis of the drum due to the applied loads is conducted using finite element method. The complete analysis shows that the UKM's drums are not strong enough for the applied braking load. It is also observed that the crack locations are in agreement with the highly computed stressed areas.
ANALISIS TEGANGAN THERMAL PADA TROMOL REM TRUK DENGAN KAPASITAS ANGKUT 6 TON IGN Wiratmaja Puja; Henry Ako Tampubolon; Untung Suhartanto
Mesin Vol. 18 No. 2 (2003)
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This paper presents drum brakes thermal stress analysis for 6 ton truck capacity, due to friction between shoe and drum for two leading shoe brakes type. The mechanical and thermal loading are analyzed for various road conditions such as straight path, curved, and downhill path, with various value of deceleration. Based on the transient heat transfer, the drum temperature distribution are calculated for various deceleration and braking time period. Using finite element techniques, the thermal stressses are obtained and the results are compared to the actual failures evidences of brake drums. It is obeserved that the real heat crack locations are in agreement with the computed stressed areas. Based on the pressure and temperature distribution, the wear rate can be obtained to estimate the technical life of the brake drum.
ANALISIS PERCABANGAN RETAK PADA MATERIAL KERAMIK PIEZOELEKTRIK IGN Wiratmaja Puja; Muhamad Hidayat; Qing Hua Qin
Mesin Vol. 20 No. 1 (2005)
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Crack branch or kink in piezoelectric body may occur due to mechanical or electric loading. This paper presents the analysis of crack branch for ceramic piezoelectric materials. This type of advanced materials is very advantageous for application in smart structures, measurements device and actuators. Utilizing the extended Stroh Formalism for elastoelectric, the boundary value problems are solved by way of Hilbert Transforms. The explicit expressions for the elastic, electric, stress and electric intesity factor, and strain energi density are presented in integral forms. These integrals are solved using Gauss-Chebysev-Quadrature. Numerical results for piezoelectric ceramics are presented to illustrate both qualitative and quantitative behaviour of the stress- electric intesity factors.
APLIKASI METODE RAIMONDI DAN BOYD PADA PERBANDINGAN ANALISIS PERFORMANSI JOURNAL BEARING LOKOMOTIF YANG MENGALAMI BEBAN IMPAK Bagus Budiwantoro; Ridha Firmansyah; IGN Wiratmaja Puja
Mesin Vol. 21 No. 2 (2006)
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Axle Lining is a type of journal bearing at wheel driver shaft in which makes locomotive traction motor possible to be supported on the mover shaft. According to hydrodynamic lubrication theory, journal bearing is designed to work under hydrodynamic lubrication condition. Film layer between journal and bearing surfaces can give less contact between those surfaces. When the bearing is working, all performance parameters such as minimum film thickness, eccentricity ratio, bearing friction coefficient, lubricant flow, maximum lubricant pressure, temperature rise of lubricant, have to be achieved thus the bearing can reach the desired life and performances. Impact load, which works to bearing, is one important factor to be noticed because it can affect bearing performance comprehensively. Using numerical Raimondi and Boyd method which developed in form of computer program, the process to determine journal bearing performance calculation can be easier and give more accurate result. The application of this method for the calculation performance import and local product show that imported journal bearing work under hydrodynamic condition for low value of impact load up to 1500 lbf (6,68 kN). Local product work under elastohydrodynamic condition for low value of impact load up to 1000 lbf (4,45 kN). Critical impact load is 1500 lbf (6,68kN) for both product which calculated using Trumpler criteria .
Co-Authors Aditianto Ramelan Agus Suprihanto Bagus Budiwantoro Budi Riyanto Hariadi Tri Prasetia Henry Ako Henry Ako Tampubolon Muhamad Hidayat Qing Hua Qin Reza Reza Ridha Firmansyah Rochim Suratman Satryo Soemantri B Untung Suhartanto Yedi R Supriyadi