KAJI EKSPERIMENTAL CIRI GETARAN PADA BANTALAN ROL DENGAN PEMBEBANAN STATIK

Any rolling bearing defect has a certain vibration response signature which can be observed through its waveform as well as frequency spectrum, such as the sideband frequencies, which indicate there is modulation phenomena among the vibration response signals. This research was carried out to study the vibration response signatures in the roll bearings due to the interaction between the static load and bearing inner/outer race waviness. This experimental research consists of FRF (Frequency Response Function) measurements to obtain the dynamic characteristics of the rolling bearing vibration, and power spectrum testing to measure the vibration response that occurs in the bearing. The shaft speed and static loads (vertical, horizontal, combination) are varied during the experimental study. Experimental results reveal Roll Passage Frequency (RPF) and its sidebands caused by the static load, and it was also found that waviness in the order of 4 at  the inner race and in the order of 6 at the outer race of the bearing

EVALUASI POLA FUNGSI RESPON FREKUENSI PADA RESPON GETARAN BANTALAN GELINDING

Rolling bearing is a mechanical component which is commonly used in industrial machinery to suppress mechanical losses due to friction. Health condition of those machines are monitored by measuring its vibration responses as normally conducted in predictive maintenance (PdM) technology. There are two important steps in PdM, i.e. frequency spectrum analysis for diagnostic purpose and control trip value which is based on the root mean square (RMS) vibration level evaluation of the machine in operation. The vibration response measuring results show, the floor noise level contributs to the increase in RMS vibration level. Floor noise found in the frequency spectrum of the rolling bearings vibration resembles the pattern obtained from the frequency response function (FRF) measurements of the rolling bearing assembly unit. The objective of this study is to evaluate the FRF patterns detected in the vibration response of a new rolling bearing installed in the measuring set up. The vibration response and FRF measurements were performed and the frequency spectrum is measured for various shaft rotating speeds as well as static loads. Floor noise signal obtained from frequency spectrums measurement shows a pattern which resembles the FRF curve of the roller bearing measuring set up. The FRF pattern of the floor noise is caused by rolling friction phenomena which generates random vibration excitation signals on the tested rolling bearing and its supporting structure

CRACK DETECTION USING OPERATING DEFLECTION SHAPE

This research presents development of vibration-based crack detection method using operating deflection shape (ODS) analysis from data measured by a Laser Doppler Vibrometer (LDV). Two types of work are conducted in this research. The first work is a numerical study, while the second work is an experimental study to verify the proposed method. In the numerical study, two types of specimen are used to simulate 2-Dimensional and 3-Dimensional problems using NASTRAN code. For the 2-Dimensional model, beams with two types of crack are tested, namely center and edge cracks. For the 3-Dimensional model, a plate specimen is tested. The length of the cracks and their locations are used as parameters to observe the ability of the proposed method to detect the existence and the location of the cracks. The results of numerical study show that the existence of cracks can be detected by using the natural frequency drops and the location of the cracks can be pinpointed by using the proposed S.Sd.D.Ms method (Square of the Second Derivative of the Deviation of the Mode Shape). In order to test the reliability of the proposed method, an experimental study is required. In this experimental study, FRF ODS measurements are conducted to derive the mode shape. Three types of specimen are measured, namely intact beam, center cracked beam, multiple center cracked beam and multiple edge cracked beam. The results of experimental study confirm that the proposed method can be used to detect the location of the cracks

MEASURING AND COMPENSATING FOR OFF-LINE TO RUNNING MACHINERY MOVEMENT

Actually, all rotating equipments which connected one to each other undergo a change in position during start-up (off-line) and this condition will affect the alignment of the shafts while running. The off-line to running movement characteristics of the vast majority of rotating machinery in industries have never been measured. It is very important to know how much movement occurred before concluding that it is insignificant and can be ignored. This paper will show the characteristics of both cold and hot misalignment. The purpose of this work is to analyze the influence of temperature to misalignment of rotating equipments that has been mentioned in some references but never been investigated. The objective of this work is to find out the characteristics of hot misalignment and to compensate for Off-Line to Running (OL2R) machinery movement. The results of the experiments and analysis show that the misalignment condition changes during operation and it strongly influences on the vibration level of the rotating machinery. In this case, the smaller the misalignment value, the smaller vibration level of the rotating machinery

KAJI KOMPUTASIONAL PENGARUH BEBAN DAN KEAUSAN TERHADAP KEKAKUAN BANTALAN ROL

This paper explores the study of numerical determination of roller bearing stiffness as a result of wear increment by using contact Hertzian method. This study is part of the research on the determination of roller bearing vibration response as a result of wear increment. In this paper, wear is assumed as diametral clearance, Cd, and force work in radial direction. Computational method shows that increasing wear causes the decrease of stiffness. The relationship between deflection and stiffness, radial load and stiffness as a function of Cd can be determined

Respons Getaran Non-Linier pada Sistem Poros-rotor Bagian I: Pengaruh Celah Bantalan

Sari. Dalam kegiatan anaiisis ini diiakukan permodelan sistem getaran dengan gaya eksitasi yang berasal dari ketidakseimbangan rotor dan ketaksesumbuan poros. Gaya eksitasi ini kemudian diteruskan ke bantalan dan selanjutnya melulaui bantalan diteruskan ke rumah bantalan. Ketaklinieran kekakuan sistem bantalan yang berasal dari celah (clearance) bantalan tersebut akan menghasilkan ciri sendiri sehinngga ciri ini dapat digunakan untuk mengidentifikasi keausan bantalan yang digunakan. Hasil analisis teoritik ini selanjutnya dibandingkan dengan data gertaran domain waktu (waveform) yang diperoleh dari kaji eksperimental pada sistem poros-tutor. Mechanical Signature Analysis of Synchronous and synchronous Excited Rotating Rotor Supported by Rolling Element BearingAbstract. An analytical model of a rotor shaft vibration system subjected to rotor unbalance and shaft misalignment excitation forces has been developed. Those excitation forces are transmitted to a bearing housing through a roller bearing housing where the vibration response is measured. The non-linearity of the bearing stiffness due to the bearing clearance reveals some specific vibration signatures, which can be utilized for bearing, wear identification. The theoretical results obtained in this study are compared with those obtained from experiment.

KONSTRUKSI MESIN PERKAKAS KONVENSIONAL DAN NC

Mesin perkakas merupakan tulang punggung suatu proses manufakturing maupun suatu sistem produksi, kualitas produk yang dihasilkan tergantung pada interaksi yang terjadi antara benda kerja, perkakas potong dan mesin perkakasnya, dalam hal ini mesin perkakas merupakan salah satu faktor dominan yang mempengaruhi ketelitian benda kerja yang dihasilkan, karenanya mesin perkakas disebut juga sebagai induk dari mesin-meisn yang ada, Dalam makalah ini dibahas pula secara singkat hasil-hasil pengkajian baik eksperimental maupun teoritik yang telah dirintis selama ini di Laboratorium Teknik Produksi, Jurusan Teknik Mesin FTI-ITB

PENERAPAN ANALISIS MODUS GETAR EKSPEFNMENTAL UNTUK IDENTIFIKASI PARAMETER MODUS GETAR STRUKTUR MEKANIK

Dalam analisis modus getar eksperimental peranan aspek pengukuran Fungsi Respon Frekuensi adalah penting karena hasilnya digunakan sabagai acuan dalam menguji keabsahan model teoritik (misal: model elemen hingga) analisis dinamik suatu struktur mekanik. Keluaran yang diperoleh dari analisis di atas adalah berupa parameter modus getar yakni: frekuensi pribadi, perbandingan redaman dan bentuk modus getar dari struktur mekanik tersebut. Besaran tersebut diperoleh melalui proses curve fitting. Dalam pengkajian ini dilakukan analisis modus getar eksperimental atas suatu struktur mekanik dan pengernbangan proses curve-fitting data eksperimental dalam domain waktu

Seminar Cad/cam

p.100,.;ill;30 cm