Main Article Content
Looseness occurs in almost all machines and can changes the vibration of the machine. In this paper, experiments were conducted by using two sets of rotor model to observe the effects of looseness on vibration values and patterns on the spectrum of unbalance and misalignment conditions. Rotor model 1 was used to simulate unbalance condition by adding mass to the disk, while rotor model 2 was used to simulate misalignment by changing the position of the bearing housings. Looseness condition was achieved by loosening the bearing housing bolts. The result of vibration observations in unbalance machine showed that looseness changed the overall value and peak values of vibration spectrum. While in machine which has shaft misalignment condition, looseness changed the vibration patterns on the spectrum.
 S. Sutar, V. Warudkar, and R. Sukathankar, “Vibration analysis of rotating machines with case studies,” Int. J. Sci. Technol. Res., vol. 7, no. 7, pp. 70–76, 2018.
 M. A. Saleem, “Detection of Unbalance in Rotating Machines Using Shaft Deflection Measurement during Its Operation,” IOSR J. Mech. Civ. Eng., vol. 3, no. 3, pp. 08–20, 2012.
 G. K. Yamamoto, C. da Costa, and J. S. da Silva Sousa, “A smart experimental setup for vibration measurement and imbalance fault detection in rotating machinery,” Case Stud. Mech. Syst. Signal Process., vol. 4, pp. 8–18, 2016.
 B. K. Kumar, G. Diwakar, and M. R. S. Satynarayana, “Determination of Unbalance in Rotating Machine Using Vibration Signature Analysis,” Int. J. Mod. Eng. Res., vol. 2, no. 5, pp. 33415–33421, 2012.
 P. Vinh Dang, L. H. Toan Do, N. Thanh Vo, T. Nghi Ngo, and H. Nam Le, “Identification of Unbalance in Rotating Machinery Using Vibration Analyse Solution,” IOP Conf. Ser. Mater. Sci. Eng., vol. 841, no. 1, 2020.
 A. Yanto, “Studi Eksperimental Getaran Sistem Poros-Rotor Akibat Imbalance Experimental Study of Vibration of Shaft-Rotor System Due to Imbalance,” vol. 7, no. 2, 2017.
 M. Senthilkumar and S. Sendhilkumar, “Experimental Study on the Effects of Misalignment in a Rotor- Bearing System,” AENSI, vol. 10, no. 6, pp. 89–93, 2016.
 A. Kurniawan, “Respon Vibrasi Overall dan Temperatur Komponen Mesin Terhadap Misalignment Axial,” KILAT, 2020.
 H. F. Wang and G. Chen, “Asynchronous vibration response characteristics of connectors with looseness fault and its verification,” Gongcheng Lixue/Engineering Mech., vol. 33, no. 4, pp. 225–232, 2016.
 G. Yang, C. Che, S. Xiao, B. Yang, T. Zhu, and S. Jiang, “Experimental Study and Life Prediction of Bolt Loosening Life under Variable Amplitude Vibration,” Shock Vib., vol. 2019, 2019.
 H. Wang et al., “Characteristics analysis of rotor-rolling bearing coupled system with fit looseness fault and its verification,” J. Mech. Sci. Technol., vol. 33, no. 1, pp. 29–40, 2019.
 M. Nataraj and G. Baskaran, “Experimental Investigation of Misalignment and Looseness in Rotor Bearing System using Bartlett Power Spectral Density,” Exp. Investig. Misalignment Looseness Rotor Bear. Syst. using Bartlett Power Spectr. Density, vol. 76, no. 5, p. 313, 2017.
 S. Wei, W. Lu, and F. Chu, “Speed characteristics of disk–shaft system with rotating part looseness,” J. Sound Vib., vol. 469, 2020.
 X. An and F. Zhang, “Pedestal looseness fault diagnosis in a rotating machine based on variational mode decomposition,” Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci., 2017.