Journal articles: 'Ambient and Forced Vibration'

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Fujino, Yozo, Masato Abe, Hajime Shibuya, Masato Yanagihara, Masashi Sato, Shun-Ichi Nakamura, and Yoshifumi Sakamoto. "Forced and Ambient Vibration Tests and Vibration Monitoring of Hakucho Suspension Bridge." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (January 2000): 57–63. http://dx.doi.org/10.3141/1696-43.

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Forced and ambient dynamic tests of the Hakucho Bridge were carried out to study the dynamic characteristics of this suspension bridge. Dense-array measurement was employed in order to capture not only natural frequencies and damping, but also the mode shapes of the bridge. The natural frequencies and mode shapes obtained from the forced and ambient vibration tests agreed well with those calculated by a three-dimensional finite element model. A new method that combines the random decrement method with the Ibrahim time domain method is proposed to systematically identify the natural frequencies, damping, and mode shapes. This method is successfully applied to ambient vibration data. It is shown that the natural frequency of the first vertical bending mode decreases noticeably as the wind speed increases. It is also shown that the shape of the first vertical bending mode changes slightly near the towers, depending on the wind velocity; this finding indicates that the change may be associated with friction in the bearings at the towers. Finally, application of the Global Positioning System to measure static displacement of the girder is explained.

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Kharrazi, Mehdi H. K., and Carlos E. Ventura. "Vibration Frequencies of Woodframe Residential Construction." Earthquake Spectra 22, no. 4 (November 2006): 1015–34. http://dx.doi.org/10.1193/1.2360699.

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Different methods of vibration measurement, such as ambient and forced vibration techniques, have been used in existing woodframe houses to determine fundamental frequency, but because of the highly nonlinear nature of this type of structural system, the reported results vary significantly. This paper discusses some of the differences of frequency values observed in various experimental studies, and identifies the source of these differences by relating the measured fundamental period to the level of shaking. The experimental results from different full-scale tests of woodframe houses and single wood shear walls are used in this paper to gain an improved understanding of the dynamic characteristics of this type of construction and to help explain the differences in results from ambient and forced vibration techniques. A simple equation to estimate forced vibration periods from ambient vibration periods is presented, and its possible application in engineering practice is discussed.

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Jafari, Mohammad Kazem, and Mohammad Davoodi. "Dynamic characteristics evaluation of Masjed Soleiman Dam using in situ dynamic tests." Canadian Geotechnical Journal 43, no. 10 (October 1, 2006): 997–1014. http://dx.doi.org/10.1139/t06-059.

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The responses to forced vibrations, ambient vibrations, and large explosives were measured for Masjed Soleiman Dam, the highest embankment dam in Iran. Based on the results of these tests, the first 23 modal frequencies of the dam were measured and the related mode shapes for the first 16 modes were identified. A modal analysis of the dam body was also performed. The effects of reservoir water level variation, the rigidity and flexibility of the foundation and abutments and their depths and inertial properties, and the effect of material properties on the dynamic characteristics of the dam body were investigated, and the first eight modes of the dam body were identified. A comparison of the results of the numerical analysis with those from the tests indicates the best fit in lower modes occurs when the complete mass foundation is considered, whereas in higher modes the massless foundation model is a better fit.Key words: embankment dam, forced vibration test, ambient vibration test, explosion, modal properties.

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Wen, Q., XG Hua, ZQ Chen, JM Guo, and HW Niu. "Modal parameter identification of a long-span footbridge by forced vibration experiments." Advances in Structural Engineering 20, no. 5 (April 11, 2017): 661–73. http://dx.doi.org/10.1177/1369433217698322.

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Performing forced vibration tests on full-scale structures is the most reliable way of determining the relevant modal parameters in structural dynamics, such as modal frequencies, mode shapes, modal damping, and modal masses. This study describes the modal identification of a double-level curved cable-stayed bridge with separate deck systems for pedestrians and vehicles via forced vibration tests. The steady-state structural responses to sinusoidal excitations produced by an electrodynamic shaker are recorded under varying excitation frequencies, and the frequency response functions are established. The measured frequency response functions are curve fitted to estimate the modal parameters. The numerical simulation of frequency response function–based modal parameter identification of an elastically multi-supported continuous beam structure is carried out, and the emphasis has been placed on the evaluation of the effect of an additional shaker mass, excitation frequency step and range, multi-mode vibration, and noise on identification results. Finally, the modal parameters for the first lateral mode of a double-level curved cable-stayed bridge are identified by forced vibration experiments, and the results are compared with those from ambient vibration tests and free vibration tests. The effect of the unmeasured wind excitation on identification is discussed. It is shown that the effect of ambient vibration is minor for wind velocity of 3–5 m/s. The damping ratios identified by forced and free vibration tests are comparable, while those from ambient vibration are subject to large variations. The modal mass obtained from forced vibration tests is in good agreement with finite element prediction, which provides design basis for mass-type dampers.

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Paultre, P., J. Proulx, and T. Bégin. "Ambient and forced-vibration tests of the Beauharnois suspension bridge." Canadian Journal of Civil Engineering 27, no. 6 (December 1, 2000): 1162–72. http://dx.doi.org/10.1139/l00-051.

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Ambient and forced vibration tests were carried out on the Beauharnois Bridge, a unique, 177-m combined suspension and cable-stayed structure near Montreal. A rehabilitation program was completed on the bridge during which the deck was completely rebuilt with an orthotropic slab on two steel trusses. The rehabilitation program also included the addition of two pairs of stay cables on both towers, creating a hybrid suspension system. The paper presents a series of dynamic tests performed to evaluate the dynamic properties and the dynamic amplification factor (DAF) for the rehabilitated bridge. The experimental program involved the measurement of vertical, transverse, and longitudinal acceleration responses of the deck and tower under ambient and controlled traffic loads. Displacement, strain, and integrated acceleration DAFs were computed under different loading conditions. Modal properties were evaluated and used to correlate a three-dimensional finite element model for the bridge, including nonlinear cable behaviour. The paper discusses the experimental setup and the techniques used to evaluate vibration frequencies, mode shapes, and the DAF. Correlation of numerical dynamic properties and experimental results is also presented. Key words: cable-stayed bridge, dynamic amplification, dynamic testing, numerical correlation, modal analysis, suspension bridge.

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Aras, Fuat. "Ambient and forced vibration testing with numerical identification for RC buildings." Earthquakes and Structures 11, no. 5 (November 25, 2016): 809–22. http://dx.doi.org/10.12989/eas.2016.11.5.809.

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PENG, XUE-LIN, and HONG HAO. "A NUMERICAL STUDY OF DAMAGE DETECTION OF UNDERWATER PIPELINE USING VIBRATION-BASED METHOD." International Journal of Structural Stability and Dynamics 12, no. 03 (May 2012): 1250021. http://dx.doi.org/10.1142/s0219455412500216.

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This paper presents a numerical investigation of the feasibility of condition monitoring of untrenched pipelines at seabed through ambient vibration measurements. A finite element (FE) model is developed to calculate the dynamic responses of pipelines to ambient wave forces. The model takes into consideration the interaction between the ocean waves, submarine pipeline, and seabed. The fluid around the pipeline is simulated using the acoustic fluid elements, while soil is simulated by springs and dashpots. The ambient hydrodynamic force in the marine environment is simulated based on the Joint North Sea Wave Observation Project (JONSWAP) spectrum. The transfer function from the wave surface elevation to the wave force is used to get the wave force spectrum. The dynamic responses of the pipe structure with different assumed damage conditions to the ambient wave forces are calculated. The calculated dynamic responses are assumed as measured ambient vibration data in condition monitoring to extract the pipeline vibration properties, which in turn are used in the FE model updating calculation to identify the pipeline conditions. Different noise levels are introduced into the calculated dynamic responses to simulate uncertainties that may arise from measurement and ambient hydrodynamic environment. The effect of noise levels on the extraction of pipeline vibration properties, and on the identification of the pipeline conditions is investigated.

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Beskhyroun, Sherif, Niusha Navabian, Liam Wotherspoon, and Quincy Ma. "Dynamic behaviour of a 13-story reinforced concrete building under ambient vibration, forced vibration, and earthquake excitation." Journal of Building Engineering 28 (March 2020): 101066. http://dx.doi.org/10.1016/j.jobe.2019.101066.

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Ozcelik, O., and C. Amaddeo. "System Identification of a Base-Isolated Bridge by Ambient and Forced Vibration Tests." Journal of Testing and Evaluation 45, no. 6 (January 24, 2017): 20150505. http://dx.doi.org/10.1520/jte20150505.

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Hariri-Ardebili, Mohammad Amin, Hamid Rahmani Samani, and Masoud Mirtaheri. "Free and Forced Vibration Analysis of an Infilled Steel Frame: Experimental, Numerical, and Analytical Methods." Shock and Vibration 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/439591.

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Structural frames with masonry infill panels make up a significant portion of the buildings constructed in earthquake-prone areas prior to the developing of the seismic design standards. In this paper, the effects of masonry panels on the vibration response of an infilled steel-frame building are investigated. Various ambient and steady state forced vibration tests are carried out to realize the dynamic characteristics of the system. 3D finite element models of the building with and without infill panels are provided based on marcomodeling theorem. A set of analytical approximate formulas are also derived to estimate the vibrational period. The natural frequencies of the building are computed using numerical, analytical, and experimental methods. The results show that neglecting the effect of infill panels leads to considerable error. Moreover, it is shown that there is good agreement among the results obtained by the three methods considering the effect of infill panels.

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Fritzen, Claus Peter. "Vibration-Based Structural Health Monitoring – Concepts and Applications." Key Engineering Materials 293-294 (September 2005): 3–20. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.3.

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This paper gives an overview on the current status of vibration-based methods for Structural Health Monitoring. All these methods have in common that a structural change due to a damage results in a more or less pronounced change of the dynamic behavior. The use of modal information is discussed, as well as the direct use of forced and ambient vibrations. From this information, different strategies can be deduced which depend on the type of measurement data (time/frequency domain) but also on the frequency spectrum. The incorporation of actuation and sensing devices into the structure leads to modern concepts of Smart Structural Health Monitoring. Examples from civil and aerospace engineering show the applicability of these methods.

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Ono, Kyosuke, and Masami Yamane. "Experimental and Theoretical Investigation of Bouncing Vibrations of a Flying Head Slider in the Near-Contact Region." Journal of Tribology 129, no. 2 (November 15, 2006): 246–55. http://dx.doi.org/10.1115/1.2464131.

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We experimentally and theoretically investigated in detail bouncing vibrations of a flying head slider in the near-contact region between the head and disk surface. By changing the Z-height in the experiment, we evaluated the effect of the pitch static angle on the ambient pressure at which unstable bouncing vibration starts and stops. We found that the touch-down and take-off pressure hysteresis decreased as the pitch static angle increased even though the flying height at the trailing edge decreased slightly. From detailed measurement of the slider dynamics at the threshold of the bouncing vibration, we found that the trailing edge of the slider was first attracted to the disk. As the pitch static angle decreased, the magnitude of the first drop of the trailing edge increased and the bouncing vibration amplitude increased more rapidly. We also measured the mode of the bouncing vibration by using two laser Doppler vibrometers simultaneously. By using an improved two-degree-of-freedom slider model, in which the small micro-waviness and the shearing force of the lubricant were taken into account, we could analyze the touch-down/take-off hysteresis, mode, and destabilization process of the bouncing vibration similar to the experimental results. We also theoretically found that either self-excited bouncing vibration with lower pitch frequency or forced vibration with higher pitch frequency was generated, depending on the magnitudes of the micro-waviness and the disturbance.

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Song, Mingming, Seyedsina Yousefianmoghadam, Mohammad-Ebrahim Mohammadi, Babak Moaveni, Andreas Stavridis, and Richard L. Wood. "An application of finite element model updating for damage assessment of a two-story reinforced concrete building and comparison with lidar." Structural Health Monitoring 17, no. 5 (November 7, 2017): 1129–50. http://dx.doi.org/10.1177/1475921717737970.

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This article investigates the performance of finite element model updating to identify the induced damage in a two-story reinforced concrete masonry-infilled building using vibration data as well as lidar (light detection and ranging) scans. The building, located in El Centro, California, was severely damaged due to the 2010 El Mayor–Cucapah (Baja California, Mexico) Earthquake, and it was planned to be demolished following a number of ambient and forced vibration tests. The forced vibration tests were performed using an eccentric mass shaker. During the testing sequence, damage was induced to the building by removing four exterior walls. The modal parameters of the structure are estimated using the ambient vibration and forced vibration measurements at the reference state and damaged state. Lidar data are also used to detect surface defects and quantify the temporal changes of surface defects caused by the wall removal and forced vibration tests. Based on site inspections, geometry measurements, and material test data, two initial finite element models are built, namely the un-tuned initial model and the tuned initial model. The tuned initial model implements stiffness reduction factors to account for the observed damage in the building at its reference state while the un-tuned model does not. Two sets of reference models are calibrated to represent the structure at the reference state using the un-tuned and tuned initial models. The reference models are then updated to fit the measured data at the damaged state of the building with damage being estimated as the loss of stiffness in updating substructures. The estimated damage is compared to the nominal value of induced damage and surface defects detected by lidar scans. The analysis of the results indicates that the un-tuned and tuned initial models provide similar updated models and damage identification results which are in good agreement with the nominal values of damage and lidar detection results.

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Ni, Yan-Chun, and Feng-Liang Zhang. "Fast Bayesian approach for modal identification using forced vibration data considering the ambient effect." Mechanical Systems and Signal Processing 105 (May 2018): 113–28. http://dx.doi.org/10.1016/j.ymssp.2017.11.007.

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Geier, R., G. De Roeck, and R. Flesch. "Accurate cable force determination using ambient vibration measurements." Structure and Infrastructure Engineering 2, no. 1 (March 2006): 43–52. http://dx.doi.org/10.1080/15732470500253123.

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Ono, Kyosuke, Masami Yamane, and Hiroshi Yamaura. "Experimental and Analytical Study of Bouncing Vibrations of a Flying Head Slider in a Near-Contact Regime." Journal of Tribology 127, no. 2 (April 1, 2005): 376–86. http://dx.doi.org/10.1115/1.1843165.

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This paper presents an experimental and analytical study of bouncing vibrations of a flying head slider in near-contact and contact regimes. In our experiment we showed that, by reducing the ambient pressure, the slider begins to touch-down and exhibit bouncing vibrations, and by increasing the ambient pressure thereafter, the slider continues to vibrate until an ambient pressure higher than the touch-down pressure. In the analysis we used a two-degrees-of-freedom slider model with linear front and rear air-bearing springs and dashpots. In a numerical simulation of slider dynamics, we considered rough surface contact of the trailing air-bearing pad with a disk, including bulk deformation, adhesion force of lubricant and friction force. The disk is assumed to have no microwaviness. From the simulation of decreasing and increasing nominal flying height, we found that the slider exhibits a bouncing vibration and touch-down/take-off hysteresis as seen in the experiment. The frequency spectrum characteristics of the bouncing vibration agree well between numerical analysis and the experiment. From a parametric study of the bouncing vibration excited by initial spacing deviation, we found that the unstable flying height range can be decreased by increasing the air-bearing stiffness and can be completely eliminated if the lubricant adhesion force or the frictional coefficient is decreased to certain small values.

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Ni, Yan-Chun, and Feng-Liang Zhang. "Uncertainty quantification in fast Bayesian modal identification using forced vibration data considering the ambient effect." Mechanical Systems and Signal Processing 148 (February 2021): 107078. http://dx.doi.org/10.1016/j.ymssp.2020.107078.

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Valdés-González, Jesús, Jaime De-la-Colina, and Carlos Alberto González-Pérez. "Experiments for seismic damage detection of a RC frame using ambient and forced vibration records." Structural Control and Health Monitoring 22, no. 2 (June 26, 2014): 330–46. http://dx.doi.org/10.1002/stc.1678.

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Mitchell, M. R., R. E. Link, Abdurrahman Şahin, and Alemdar Bayraktar. "SignalCAD: A Digital Signal Processing Software for Forced and Ambient Vibration Testing of Engineering Structures." Journal of Testing and Evaluation 38, no. 1 (2010): 102458. http://dx.doi.org/10.1520/jte102458.

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D’Ambrisi, A., V. Mariani, and M. Mezzi. "Seismic Assessment of a Historical Tower with Advanced Numerical Model Tuned on Ambient Vibration Data." Advanced Materials Research 133-134 (October 2010): 617–22. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.617.

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This paper deals with the dynamic characterization and the evaluation of the seismic response of the medieval civic tower of Soncino (Cremona, Italy). The dynamic characteristics and the mechanical properties of the masonry tower are evaluated through ambient vibration tests, which provide results in a fast and non destructive way with respect to the traditional methods such as forced vibration tests. Nonlinear static and dynamic analyses are performed on a finite element model of the tower calibrated on the results of the dynamic identification. The damage levels and the seismic capacity of the structure are also evaluated. The obtained results allow to predict the seismic behaviour of the tower and to define possible strengthening and restoration interventions.

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Li, Wei Zhao, Zong Lin Wang, and Da Wei Sun. "Dynamic Assessment about Simple-Supported Girder Bridge." Applied Mechanics and Materials 105-107 (September 2011): 1272–75. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1272.

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The objective of this study is to introduce a dynamic assessment method about simple-supported girder bridge .This paper introduces the dynamic test contents, test methods, test results and the assessment index. The dynamic tests included ambient vibration tests which were used to identify the bridge modal parameters and forced vibration tests based on controlled traffic loads which were used to obtain the and vibratory response. The analytical results showed that the dynamic performance was in good condition and the bridge had great potential of carrying capacity. This method provided effective means for the assessment of the existing simple-supported girder bridge.

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Soyoz, Serdar, Ertugrul Taciroglu, Kutay Orakcal, Robert Nigbor, Derek Skolnik, Hilmi Lus, and Erdal Safak. "Ambient and Forced Vibration Testing of a Reinforced Concrete Building before and after Its Seismic Retrofitting." Journal of Structural Engineering 139, no. 10 (October 2013): 1741–52. http://dx.doi.org/10.1061/(asce)st.1943-541x.0000568.

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Kohler, Monica D., Paul M. Davis, and Erdal Safak. "Earthquake and Ambient Vibration Monitoring of the Steel-Frame UCLA Factor Building." Earthquake Spectra 21, no. 3 (August 2005): 715–36. http://dx.doi.org/10.1193/1.1946707.

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Dynamic property measurements of the moment-resisting steel-frame University of California, Los Angeles, Factor building are being made to assess how forces are distributed over the building. Fourier amplitude spectra have been calculated from several intervals of ambient vibrations, a 24-hour period of strong winds, and from the 28 March 2003 Encino, California ( ML=2.9), the 3 September 2002 Yorba Linda, California ( ML=4.7), and the 3 November 2002 Central Alaska ( Mw=7.9) earthquakes. Measurements made from the ambient vibration records show that the first-mode frequency of horizontal vibration is between 0.55 and 0.6 Hz. The second horizontal mode has a frequency between 1.6 and 1.9 Hz. In contrast, the first-mode frequencies measured from earthquake data are about 0.05 to 0.1 Hz lower than those corresponding to ambient vibration recordings indicating softening of the soil-structure system as amplitudes become larger. The frequencies revert to pre-earthquake levels within five minutes of the Yorba Linda earthquake. Shaking due to strong winds that occurred during the Encino earthquake dominates the frequency decrease, which correlates in time with the duration of the strong winds. The first shear wave recorded from the Encino and Yorba Linda earthquakes takes about 0.4 sec to travel up the 17-story building.

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Yu, Eunjong, Derek Skolnik, Daniel H. Whang, and John W. Wallace. "Forced Vibration Testing of a Four-Story Reinforced Concrete Building Utilizing the nees@UCLA Mobile Field Laboratory." Earthquake Spectra 24, no. 4 (November 2008): 969–95. http://dx.doi.org/10.1193/1.2991300.

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The nees@UCLA mobile field laboratory was utilized to collect forced and ambient vibration data from a four-story reinforced concrete (RC) building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively. Floor accelerations, interstory displacements, and column and slab curvature distributions were monitored during the tests using accelerometers, linear variable differential transformers (LVDTs) and concrete strain gauges. The use of dense instrumentation enabled verification of common modeling assumptions related to rigid diaphragms and soil-structure-interaction. The first six or seven natural frequencies, mode shapes, and damping ratios were identified. Significant decreases in frequency corresponded to increases in shaking amplitude, most notably in the N-S direction of the building, most likely due to preexisting diagonal joint cracks that formed during the Northridge earthquake.

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Liu, Kun-Sung, and Yi-Ben Tsai. "Observed Natural Frequencies, Damping Ratios, and Mode Shapes of Vibration of a 30-Story Building Excited by a Major Earthquake and Typhoon." Earthquake Spectra 26, no. 2 (May 2010): 371–97. http://dx.doi.org/10.1193/1.3385471.

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The safety of building structures and contents, as well as the comfort of occupants, under such strong forces as earthquakes and typhoons remain major engineering concerns. In order to improve our understanding of building structural responses, records of a structural array in the 30-story PS Building in Taipei from the M7.6 Chi-Chi earthquake and Typhoon Aere are analyzed. In addition, wind data measured at the Taipei Meteorological Station are also used. First, the field measurement data clearly demonstrate that serviceability of the PS Building met the criteria for occupant comfort during Typhoon Aere. Secondly, several structural vibration parameters of this highrise building, including the transfer functions, natural frequencies, damping ratios and mode shapes, excited by the Chi-Chi earthquake, Typhoon Aere, and ambient vibrations are also determined and compared. The results show the frequency of the first mode for the longitudinal components is approximately 8.6% lower for the earthquake than the ambient vibrations. The transverse mode frequencies behave similarly. In contrast, frequency changes from the typhoon to ambient vibrations are in the third decimal (1.3% and 0.9% lower in the longitudinal and transverse directions, respectively), indicating little nonlinearity. The damping ratios of the PS Building apparently increase with vibration amplitudes. Finally, results of a spectral ratio analysis of the Chi-Chi earthquake data do not indicate significant SSI effects in the longitudinal and transverse directions.

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Ta, Minh-Nghi, Joseph Lardiès, and Berthillier Marc. "Natural Frequencies and Modal Damping Ratios Identification of Civil Structures from Ambient Vibration Data." Shock and Vibration 13, no. 4-5 (2006): 429–44. http://dx.doi.org/10.1155/2006/625927.

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Damping is a mechanism that dissipates vibration energy in dynamic systems and plays a key role in dynamic response prediction, vibration control as well as in structural health monitoring during service. In this paper a time domain and a time-scale domain approaches are used for damping estimation of engineering structures, using ambient response data only. The use of tests under ambient vibration is increasingly popular today because they allow to measure the structural response in service. In this paper we consider two engineering structures excited by ambient forces. The first structure is the 310 m tall TV tower recently constructed in the city of Nanjing in China. The second example concerns the Jinma cable-stayed bridge that connects Guangzhou and Zhaoqing in China. It is a single tower, double row cable-stayed bridge supported by 112 stay cables. Ambient vibration of each cable is carried out using accelerometers. From output data only, the modal parameter are extracted using a subspace method and the wavelet transform method.

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Feng, M. Q., J. M. Kim, and H. Xue. "Identification of a Dynamic System Using Ambient Vibration Measurements." Journal of Applied Mechanics 65, no. 4 (December 1, 1998): 1010–21. http://dx.doi.org/10.1115/1.2791895.

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This paper demonstrates how ambient vibration measurements at a limited number of locations can be effectively utilized to estimate parameters of a finite element model of a large-scale structural system involving a large number of elements. System identification using ambient vibration measurements presents a challenge requiring the use of special identification techniques, which can deal with very small magnitudes of ambient vibration contaminated by noise without the knowledge of input forces. In the present study, the modal parameters such as natural frequencies, damping ratios, and mode shapes of the structural system were estimated by means of appropriate system identification techniques including the random decrement method. Moreover, estimation of parameters such as the stiffness matrix of the finite element model from the system response measured by a limited number of sensors is another challenge. In this study, the system stiffness matrix was estimated by using the quadratic optimization involving the computed and measured modal strain energy of the system, with the aid of a sensitivity relationship between each element stiffness and the modal parameters established by the second-order inverse modal perturbation theory. The finite element models thus identified represent the actual structural system very well, as their calculated dynamic characteristics satisfactorily matched the observed ones from the ambient vibration test performed on a large-scale structural system subjected primarily to ambient wind excitations. It is noted that newly developed optical fiber accelerometers were used for this ambient vibration test. The dynamic models identified by this study will be used for design of an active mass damper system to be installed on this structure for suppressing its wind vibration.

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Ventura, C. E., A. J. Felber, and S. F. Stiemer. "Determination of the dynamic characteristics of the Colquitz River Bridge by full-scale testing." Canadian Journal of Civil Engineering 23, no. 2 (April 1, 1996): 536–48. http://dx.doi.org/10.1139/l96-058.

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This paper presents the results of full-scale tests performed at the Colquitz River Bridge near Victoria, British Columbia (B.C.), Canada, during September 1992 to determine the dynamic characteristics of the structure. The five-span bridge was completed in 1954 and is part of the Trans-Canada Highway. It is 82.68 m long and 11.89 m wide, and has six continuous steel girders supporting a 175 mm thick concrete deck. This particular bridge was chosen for testing because of its typical nature of many B.C. bridges, its location in an area of high seismic risk, and its excellent site accessibility. The tests included extensive measurements of ambient vibrations induced by traffic and other sources to determine the dynamic characteristics of the bridge. The most significant vertical and lateral mode shapes and associated periods of vibration were determined from vibration measurements at more than 50 different locations of the deck, piers, and abutments. Although a large amount of data were collected, they were quickly processed and analyzed with an innovative system developed at The University of British Columbia. One of the important features of this system is that it permits the identification of the principal modes of vibration immediately after the data have been collected. In addition to the ambient vibration tests, quick release pullback tests were conducted to verify modal frequencies determined from the ambient vibration tests and to determine the damping of the fundamental modes. These tests consisted of loading the bridge at a selected location with a force of about 90 kN and then releasing this load very quickly to induce free vibrations. The information obtained from the field tests was used to refine a computer finite element model of the bridge, which, in turn, was used to gain insight into the dynamic behaviour of specific components of the bridge. Further, this information was used later by the bridge owner to evaluate the bridge's expected response during an earthquake. Key words: steel bridges, dynamic response, full-scale tests.

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Pan, Bo, Wei Zhang, Shuai Zheng, Ming-liang Zhou, Chun-fa Zhao, and Billie F. Spencer. "Modelling Ambient Vibration Responses Induced by Operation of Metro Train on Curved Rail Segment with Small Curvature Radius." Mathematical Problems in Engineering 2020 (February 22, 2020): 1–17. http://dx.doi.org/10.1155/2020/1584624.

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The torsional effect of the tracks on curved segment intensifies the ambient vibration response induced by Metro operation. This paper studies the ambient vibration responses induced by the operation of the Metro train on curved rail segments. By taking the curved segment of Hangzhou Metro Line 1 of China as an example, the wheel-rail model employing the multibody dynamics is demonstrated; the dynamic wheel-rail force of a B-type vehicle passing through a 350 m radius curved segment is also calculated. A finite element method model of the track-tunnel-soil-building is developed and verified by comparing the measured results with the simulated ones. Then, we analyzed the ambient vibration responses induced by the Metro operation. The results show that the horizontal vibration induced by the Metro train, on curved segments, cannot be ignored. When propagating on the ground, the variation trend of the horizontal vibration acceleration is greater than that of the vertical vibration. The horizontal vibration attenuates faster than the vertical vibration. The secondary vibration along the horizontal direction yields a significant amplifying effect upon the building. The vibration level increases with the height of the building, along the horizontal direction, but the vertical vibration level changes negligibly. The insight exhibits the influence level of the horizontal action of the Metro train wheels to the tracks, which can be referred by the practitioners for the planning and operation.

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Lin, A. N., and B. A. Verser. "Microcomputer Based Data Acquisition System for Dynamic Testing." Earthquake Spectra 3, no. 2 (May 1987): 299–313. http://dx.doi.org/10.1193/1.1585430.

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The availability of capable and relatively inexpensive microcomputers and versatile expansion devices has revolutionized education, research, and practice in engineering. A data acquisition and analysis system for use in full scale and large model dynamic testing based on a popular series of microcomputer has been developed. “Quick-look” and preliminary frequency analysis of data are completed in the microcomputer environment, while more detailed frequency domain analysis of single and dual channel data are completed in the mainframe environment. The system has been used for ambient and forced vibration testing of several prototype structures and large models.

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LIVAOGLU, RAMAZAN, ALPER TURAN, M. HESHAM EL NAGGAR, and ADEM DOGANGUN. "THE NUMERICAL AND EMPIRICAL EVALUATION OF STRUCTURAL PERFORMANCE OF ELEVATED TANKS CONSIDERING SOIL–STRUCTURE INTERACTION EFFECTS." Journal of Earthquake and Tsunami 06, no. 02 (June 2012): 1250008. http://dx.doi.org/10.1142/s179343111250008x.

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Water tanks are an essential lifeline whose continuing availability and serviceability immediately after earthquake events are crucial for providing undisrupted emergency services. Their seismic performance is, therefore, of paramount importance. The seismic response of an elevated liquid tank situated on a soft soil deposit was studied by means of field vibration tests and numerical simulations. The ambient and forced vibration tests were conducted to identify the soil–structure interaction (SSI) effects on the small strain dynamic behavior of the structure. A series of time domain numerical analyses were performed to evaluate the seismic performance of these structures from a performance based design point of view. The results showed that consideration of SSI increased the displacement demand significantly. Thus, the calculated maximum displacement demand for supporting frame components of the tank may be underestimated significantly when the SSI effects are neglected. In addition, the seismic induced shear forces considering SSI effects were much smaller than the seismic shear forces for the fixed based case. For some soil types, the effect of this reduction on the overall response may become more prominent than the structural ductility mechanism. This resulted in the failure mechanism being initiated by a coupled compression — bending moment effect, rather than shear failure. Finally, the sloshing response is significantly increased due to the SSI.

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SILVA, M. S., and F. A. NEVES. "Modal identification of Bridge 44 of the Carajás Railroad and numerical modeling using the finite element method." Revista IBRACON de Estruturas e Materiais 13, no. 1 (February 2020): 39–68. http://dx.doi.org/10.1590/s1983-41952020000100005.

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Abstract Regular use and the effects of time can affect the behavior of a structure. Over time, problems such as the occurrence of small fissures, oxidation of steel elements, and excessive displacements at some points may arise in a structure. In this context, the monitoring of structures through experimental tests has gained more importance, because it allows for the identification of the dynamic characteristics (natural frequencies, mode shapes, and damping rate) of structures. The dynamic characteristics can be obtained through forced vibration tests, which are based on measuring the response of a structure subjected to an excitation of known magnitude, or through tests in which only the structural response is measured, such as free vibration and ambient vibration tests. The present study aims to identify the modal parameters of bridge 44 of the Carajás Railroad, using experimental data obtained on site by monitoring the vibration caused by a group of people jumping, and it compares them with the results obtained through numerical modeling performed using the finite element method, developed in CSiBridge. The modal parameters were obtained using the commercial software ARTeMIS Modal, and stochastic subspace identification was used for modal identification.

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Liebold, Florian, Stephan Wiegand, and Ronny Käso. "Reaction Wheel Disturbance Characterization by Analysis of Micro-Vibration Measurements." Applied Mechanics and Materials 232 (November 2012): 445–49. http://dx.doi.org/10.4028/www.scientific.net/amm.232.445.

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Structural stability of satellites is of vital significance for the operation of sophisticated payload systems. Therefore manufacturers of satellite components, such as reaction wheels, make huge efforts to assure the convenient vibration behavior of their products. To meet that demand a device for the detection of mechanical oscillations with very small amplitudes was developed. The described micro-vibration test-bench allows the detection of vibrations with amplitudes > 10 5 Newton in a frequency range of < 20 kHz generated by a test item with a mass up to 30 kg. The quality of the thereby obtained data makes it possible to identify the sources of the observed vibration. The high information content of the measurements originates from a set of high resolution force sensors, variably arranged on a mechanically isolated platform. The sensitivity of the used equipment (charge cables, charge amplifiers and signal analyzers) and its resistance to ambient disturbances allow the high accuracy of the measurement as mentioned above. The described micro-vibration test-bench additionally provides opportunity to detect production errors non-destructively and helps to reduce the inherent noise of the item under test. It therefore represents a reliable measurement device to quantify and assess detrimental vibrations.

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Fu, Qinghong, Xianhua Chen, Degou Cai, and Liangwei Lou. "Mechanical Characteristics and Failure Mode of Asphalt Concrete for Ballastless Track Substructure Based on In Situ Tests." Applied Sciences 10, no. 10 (May 20, 2020): 3547. http://dx.doi.org/10.3390/app10103547.

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Asphalt concrete paved on the surface of a roadbed as a ballastless track substructure has an excellent waterproofing and vibration attenuation performance. However, the mechanical characteristics and the failure mode of this structure under the actions of a cyclic train load and ambient air temperature changes are still unclear. Therefore, a test section of an asphalt concrete substructure was constructed based on a high-speed railway ballastless track project in north China. In situ forced vibration tests and temperature-induced deformation monitoring tests were performed to investigate the mechanical responses of the asphalt concrete, respectively. Test results show that the bottom of the asphalt concrete layer is in the tensile state under the action of the cyclic train load. The surface of the asphalt concrete in contact with the base plate is subjected to tensile stress near the expansion joint under the action of the negative temperature gradient. Changes in the ambient temperature lead to more significant mechanical responses of the asphalt concrete substructure than the cyclic train load, especially near the expansion joint of the base plate. Therefore, the passive tensile failure mode may occur near the expansion joint of the base plate. However, it has also proved that setting isolation layers under the base plate near the expansion joint is an effective method to significantly reduce responses near the expansion joint in this research.

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Trigona, C., N. Dumas, L. Latorre, B. Andò, S. Baglio, and P. Nouet. "Exploiting Benefits of a Periodically-Forced Nonlinear Oscillator for Energy Harvesting from Ambient Vibrations." Procedia Engineering 25 (2011): 819–22. http://dx.doi.org/10.1016/j.proeng.2011.12.201.

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FUJINO, Yozo, Masato ABE, Tomonori NAGAYAMA, and Kenji IKEDA. "Detection of Unsteady Aerodynamic Forces in a Suspension Bridge from Ambient Vibration Monitoring." Wind Engineers, JAWE 2003, no. 94 (2003): 37–49. http://dx.doi.org/10.5359/jawe.2003.37.

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Lin, Ji-Tzuoh, Barclay Lee, and Bruce W. Alphenaar. "Acceleration Threshold Reduction for Nonlinear Energy Harvesting." International Journal of Structural Stability and Dynamics 14, no. 08 (November 25, 2014): 1440013. http://dx.doi.org/10.1142/s0219455414400136.

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Nonlinear coupling of a piezoelectric cantilever to an external magnetic force increases the power harvested from a broadband vibration source for relatively large acceleration vibrations. A threshold exists in the minimum acceleration needed for enhancement of the cantilever response. Below this threshold the nonlinear coupling damps the cantilever motion, and the power output is reduced compared to the noncoupled cantilever. By reducing the size of the coupling magnet, the acceleration required to scavenge usable power can be greatly reduced. The smaller diameter magnet decreases the spatial extent of the magnetic force, reducing the acceleration required to surmount the local potential barrier. The experiments result in a six-fold decrease in the acceleration threshold, to levels comparable to those observed in ambient environmental vibrations. The results are in good agreement with numerical calculations.

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Shrestha, Ramila, and Sudip Karanjit. "Comparative study on the fundamental time period of RC buildings based on codal provision and ambient vibration test – a case study of Kathmandu Valley." Journal of Science and Engineering 4 (April 3, 2017): 31–37. http://dx.doi.org/10.3126/jsce.v4i0.22378.

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For the proper design of any structure, its fundamental properties should be known. The fundamental time period is a primary consideration for seismic design. Generally empirical relations given by code are used in design of building structure, where time period is the function of height and lateral dimension in most cases. But, these empirical relations given by codes are not verified in the context of Nepal. For existing structures, in addition to code formulas and available analytical tools, such as modal analyses, various methods of testing, including ambient and forced vibration testing procedures may be used to determine fundamental time period. In this study, the fundamental period of the 31 RC infill buildings located in Kathmandu valley was identified using ambient motions recorded at each building. Ambient vibration measurements of buildings have been performed by using geophone. Fundamental time periods evaluated experimentally and calculated by different codal formulas were compared. Single variable regression analysis was done, and time period in relation with height is evaluated. In this analysis, codal time period was found higher than experimental one. Multi-variable regression analysis was also done, and the relation between time period, height and lateral dimension was formulated. From multivariable regression formulation, it was concluded that the effect of base dimension of building to fundamental time period is very less. It can be concluded that the fundamental time period of RC building in our current practice can be better correlated by height only relation (T = CHa) than by height and base-dimension relation (T = C H/√D) given by code. Fundamental time period calculated from codal formula for RC building with infill and from experiment was found near in most cases.

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Majer, Zdeněk, Oldřich Ševeček, Kateřina Štegnerová, Ondřej Rubeš, Pavel Tofel, and Zdenek Hadas. "Analysis of Maximal Operation Amplitudes of Piezoelectric Vibration Energy Harvesters." Key Engineering Materials 827 (December 2019): 324–29. http://dx.doi.org/10.4028/www.scientific.net/kem.827.324.

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The paper deals with an analysis of maximal operation amplitudes of piezoelectric energy harvesting systems generating electrical energy from ambient vibrations. Energy harvesting systems could be very interesting alternative for autonomous powering of ultra-low power electronics, sensors and wireless communication. A design of piezoelectric vibration energy harvester is based on the cantilever beam design with active piezoelectric layers. The output power is proportional to an amplitude of relative oscillation of this resonance mechanism. This paper presents an analysis based on the simulation model of multidisciplinary piezoelectric energy harvesting device, enabling an optimization of its key parameters ensuring a maximal efficiency of the system. Such analysis is also essential for development of new energy harvesting systems formed of new smart materials and structures which could be integrated in future development processes.

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Jiang, Junxiang, Shaogang Liu, Lifeng Feng, and Dan Zhao. "A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics." Micromachines 12, no. 4 (April 14, 2021): 436. http://dx.doi.org/10.3390/mi12040436.

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Piezoelectric vibration energy harvesting technologies have attracted a lot of attention in recent decades, and the harvesters have been applied successfully in various fields, such as buildings, biomechanical and human motions. One important challenge is that the narrow frequency bandwidth of linear energy harvesting is inadequate to adapt the ambient vibrations, which are often random and broadband. Therefore, researchers have concentrated on developing efficient energy harvesters to realize broadband energy harvesting and improve energy-harvesting efficiency. Particularly, among these approaches, different types of energy harvesters adopting magnetic force have been designed with nonlinear characteristics for effective energy harvesting. This paper aims to review the main piezoelectric vibration energy harvesting technologies with magnetic coupling, and determine the potential benefits of magnetic force on energy-harvesting techniques. They are classified into five categories according to their different structural characteristics: monostable, bistable, multistable, magnetic plucking, and hybrid piezoelectric–electromagnetic energy harvesters. The operating principles and representative designs of each type are provided. Finally, a summary of practical applications is also shown. This review contributes to the widespread understanding of the role of magnetic force on piezoelectric vibration energy harvesting. It also provides a meaningful perspective on designing piezoelectric harvesters for improving energy-harvesting efficiency.

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Majer, Zdeněk, Oldřich Ševeček, Zdeněk Machů, Kateřina Štegnerová, and Michal Kotoul. "Optimization of Design Parameters of Fracture Resistant Piezoelectric Vibration Energy Harvester." Key Engineering Materials 774 (August 2018): 416–22. http://dx.doi.org/10.4028/www.scientific.net/kem.774.416.

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This paper is focused on an analysis of a multilayer ceramic-based piezoelectric vibration energy harvester, which could be excited by ambient vibrations or external forces and thus provide a useful source of electricity for modern electronics. The proposed multilayer concept of the energy harvester enables introduction of tensile / compressive residual stresses inside particular layers. These stresses are intended to be used for enhancement of the harvester ́s fracture resistance and simultaneously for the improvement of the energy gain upon its operation. A crack arrest, by means of compressive residual stresses (in the outer “non-piezo” layer), will be utilized to this end. Primarily, the extended classical laminate theory (taking into account the piezoelectric characteristics of selected layers) will be used to define various designs of particular layers with various levels of residual stresses inside them. The weight function method is subsequently employed to select a design, which is most resistant to propagation of preexisting cracks. Selected laminate configurations are verified by means of FE simulations. Such analysis is essential for development of new energy harvesting systems formed of new smart materials and structures, which could be integrated in future development processes.

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Sequera Gutierrez, Diego, Luis Felipe Solano Rodríguez, Edgar Eduardo Muñoz Díaz, Yezid Alexander Alvarado Vargas, Jesús Daniel Villalba Morales, and Isabel Gasch Molina. "Updating the finite element model of a Colombian Bridge with Ansys." DYNA 87, no. 212 (January 1, 2020): 209–18. http://dx.doi.org/10.15446/dyna.v87n212.79785.

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Updating structural model is a knowledge field that have been studied in the last decades to guarantee the reliability on the model defined to represent the behavior of a structure, but generally implies the use of different software to carry out the different parts of the process. This paper presents the updating of the finite element model of a curve-alignment reinforced concrete bridge located near to the city of Ubaté in Colombia by using the optimization tool available in software Ansys and ambient vibration measurements. The use of such type of information avoids to carry out forced-vibration test, which affect the normal operation of the bridge. The objective function corresponds to the minimization of the error between analytical and experimental natural frequencies of the bridge. The design variables correspond to the material properties of the concrete and the elastomeric bearings. Results show that the error was decreased to less than 2%. The sensibility analysis allowed to determine which variables are more sensible to affect the natural frequencies in the structure.

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Wang, Jian, Cong Zhao, Shi Ming Zhang, and Jiang Bo Zou. "Quartz Crystal Double-Ended Tuning Fork Resonator for High Resolution Force Sensing." Key Engineering Materials 609-610 (April 2014): 1181–84. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.1181.

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This paper reports a novel piezoelectric quartz crystal double-ended tuning fork (DETF) resonator with vibration attenuation structure, which is suitable for high resolution force sensing. The DETF resonator was designed to work in the fundamental flexure mode, and manufactured along the Y direction based on the Z-cut quartz crystal wafer using photolithographic and anisotropic chemical etching of quartz crystal. The resonance frequency of the DETF resonator is 39.1KHz. Vibration amplitude of the DETF resonator was measured and the experimental results show that vibration amplitude of the joint of DETF resonator is almost three orders of magnitude lower than that of midpoint of DETF, and the quality factor is up to 7750 at ambient condition and 59600 in vacuum, respectively.

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Lee, B. S., S. C. Lin, and W. J. Wu. "Fabrication and Evaluation of a MEMS Piezoelectric Bimorph Generator for Vibration Energy Harvesting." Journal of Mechanics 26, no. 4 (December 2010): 493–99. http://dx.doi.org/10.1017/s172771910000469x.

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ABSTRACTWe present the development of a MEMS piezoelectric bimorph generator, a cantilever type bimorph which was formed by laminating two PZT piezoelectric layers. Our bimorph generator can scavenge mechanical energy from ambient vibrations and transform it into useful electrical energy. Two poling configurations of the PZT piezoelectric layers of our bimorph MEMS generator were fabricated and tested. A tip proof mass used for adjusting the resonance frequency was also demonstrated. Experimental results confirm that our device possessed a maximum open-circuit output voltage of 1.91VP-P and a 3.42VP-P for a parallel polarization device and a serial polarization device, respectively with a 2g externally applied vibration. At an optimal resistive load, the maximum output power was 1.548μ–W and 1.778μ–W for a parallel polarization device and a serial polarization device, respectively.

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Stromquist-LeVoir, Gannon, Kevin F. McMullen, Arash E. Zaghi, and Richard Christenson. "Determining Time Variation of Cable Tension Forces in Suspended Bridges Using Time-Frequency Analysis." Advances in Civil Engineering 2018 (June 5, 2018): 1–13. http://dx.doi.org/10.1155/2018/1053232.

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A feasibility study was conducted to develop a novel method to determine the temporal changes of tensile forces in bridge suspender cables using time-frequency analysis of ambient vibration measurements. An analytical model of the suspender cables was developed to evaluate the power spectral density (PSD) function of a cable with consideration of cable flexural stiffness. Discrete-time, short-time Fourier transform (STFT) was utilized to analyze the recorded acceleration histories in both time and frequency domains. A mathematical convolution of the analytical PSD function and time-frequency data was completed to evaluate changes in cable tension force over time. The method was implemented using acceleration measurements collected from an in-service steel arch bridge with a suspended deck to calculate the temporal variation in cable forces from the vibration measurements. The observations served as proof of concept that the proposed method may be used for cable fatigue life calculations and bridge weigh-in-motion studies.

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Fang, Yao-Min, and Jun-Ping Pu. "Field Tests and Simulation of Lion-Head River Bridge." Shock and Vibration 14, no. 3 (2007): 181–228. http://dx.doi.org/10.1155/2007/348640.

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Lion-Head River Bridge is a twin bridge in parallel position. The east-bounded was designed and constructed as a traditional prestress concrete box girder bridge with pot bearings; and the west-bounded was installed with seismic isolation devices of lead rubber bearings. The behavior of the isolated bridge is compared with that of the traditional bridge through several field tests including the ambient vibration test, the force vibration test induced by shakers, the free vibration test induced by a push and fast release system, and the truck test. The bridges suffered from various extents of damage due to the Chi-Chi and the Chi-I earthquakes of great strength during the construction and had been retrofitted. The damage was reflected by the change of the bridges' natural frequencies obtained from the ambient vibration tests. The models of the two bridges are simulated by the finite element method based on the original design drawings. Soil-structure interaction was also scrutinized in this study. The simulation was then modified based on the results from the field tests. Dynamic parameters of bridges are identified and compared with those from theoretical simulation. The efficiency is also verified to be better for an isolated bridge.

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Liu, Bing, and Li Guo Sun. "Modal Parameter Identification and Numerical Simulation for Self-anchored Suspension Bridges Based on Ambient Vibration." E3S Web of Conferences 38 (2018): 03033. http://dx.doi.org/10.1051/e3sconf/20183803033.

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This paper chooses the Nanjing-Hangzhou high speed overbridge, a self-anchored suspension bridge, as the research target, trying to identify the dynamic characteristic parameters of the bridge by using the peak-picking method to analyze the velocity response data under ambient excitation collected by 7 vibration pickup sensors set on the bridge deck. The ABAQUS is used to set up a three-dimensional finite element model for the full bridge and amends the finite element model of the suspension bridge based on the identified modal parameter, and suspender force picked by the PDV100 laser vibrometer. The study shows that the modal parameter can well be identified by analyzing the bridge vibration velocity collected by 7 survey points. The identified modal parameter and measured suspender force can be used as the basis of the amendment of the finite element model of the suspension bridge. The amended model can truthfully reflect the structural physical features and it can also be the benchmark model for the long-term health monitoring and condition assessment of the bridge.

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Omrani, Roshanak, Ralph E. Hudson, and Ertugrul Taciroglu. "Story-by-story estimation of the stiffness parameters of laterally-torsionally coupled buildings using forced or ambient vibration data: I. Formulation and verification." Earthquake Engineering & Structural Dynamics 41, no. 12 (December 20, 2011): 1609–34. http://dx.doi.org/10.1002/eqe.1192.

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Lai, S. K., C. Wang, L. H. Zhang, and Y. Q. Ni. "Realizing a Self-powered Real-time Monitoring System on High-speed Trains." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 6 (August 1, 2021): 434–41. http://dx.doi.org/10.3397/in-2021-1476.

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The development of the worldwide high-speed rail network is expanding at a rapid pace, imposing great challenges on the operation safety. Recent advances in wireless communications and information technology can integrate the Internet of Things and cloud computing to form a real-time monitoring platform of high-speed trains. To realize this system, a sustainable power source is indispensable. In this case, an ideal solution is to deploy a vibration-based energy harvester instead of batteries for the electrical supply of wireless sensors/devices, as vibrations induced by rail/wheel contact forces and vehicle dynamics are an abundant energy source. To address this challenge, a multi-stable, broadband and tri-hybrid energy harvesting technique was recently proposed, which can work well under low-frequency, low-amplitude, and time-varying ambient sources. In this work, we will introduce our idea, following the recently proposed energy harvester and the dynamic responses of a train vehicle, to design a self-sustained sensing system on trains. Supported by this self-powered system, accelerometers and microphones deployed on an in-service train (in axle boxes/bogie frames) can measure vibration and noise data directly. The correlation of the vibration and noise data can then be analyzed simultaneously to identify the dynamic behavior (e.g., wheel defects) of a moving train.

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Prażnowski, Krzysztof, Andrzej Bieniek, Jarosław Mamala, and Adam Deptuła. "The Use of Multicriteria Inference Method to Identify and Classify Selected Combustion Engine Malfunctions Based on Vehicle Structure Vibrations." Sensors 21, no. 7 (April 2, 2021): 2470. http://dx.doi.org/10.3390/s21072470.

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Internal combustion engines are among the most commonly used propulsion units for drive systems in various industries such as land transportation, maritime transportation, and power generation. Their operation involves a continuous change of technical condition as a result of not only the combustion process but also their operation under conditions of variable load or ambient impact. It is therefore important to monitor the technical condition of internal combustion engines to ensure high performance and reliability over their lifetime. The article presents the test results obtained from incorrect operation of an internal combustion engine as a result of forced failures of the ignition and injection system. On this basis, a multicriteria comparison of the signal analysis of engine block vibrations was made, after the transformation of the signal from the time domain to the frequency domain, by using the induction technique obtained from the operation of decision tree algorithms. For this purpose, the amplitude spectrum in the frequency domain, scaled to absolute values of discretization for which teaching and testing data tables were created for successive harmonics, was determined for the engine block vibration signal being tested. On the basis of the developed algorithm using decision trees, a multicriteria data table was analyzed for which a compatibility path for the analyzed engine block vibration signal is created. In this way, it is confirmed with a specified degree of effectiveness, depending on the point of operation of the engine resulting from its crankshaft speed, that there is a possibility of detecting a preset ignition or injection system malfunction in the technical condition of the internal combustion engine with a probability up to about 72%.

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Journal articles on the topic 'Ambient and Forced Vibration'

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