Anders Brandt¹, Marta Berardengo², Stefano Manzoni³, Marcello Vanali², Alfredo Cigada³

Sound & Vibration, Vol.52, No.3, pp. 18-22, 2018, DOI:10.32604/sv.2018.03872

Abstract Methods for scaling mode shapes determined by operational modal analysis (OMA) have been extensively investigated in the last years. A recent addition to the range of methods for scaling OMA mode shapes is the so-called OMAH technique, which is based on exciting the structure by harmonic forces applied by an actuator. By applying harmonic forces in at least one degree-of-freedom (DOF), and measuring the response in at least one response DOF, while using at least as many frequencies as the number of mode shapes to be scaled, the mode shape scaling (modal mass) of all modes of interest may be… More >

Deborah Fowler¹, Garrett Lopp², Dhiraj Bansal³, Ryan Schultz⁴, Matthew Brake⁵, Micah Shepherd⁶

Sound & Vibration, Vol.52, No.3, pp. 12-17, 2018, DOI:10.32604/sv.2018.03864

Abstract Acoustoelastic coupling occurs when a hollow structure’s in-vacuo mode aligns with an acoustic mode of the internal cavity. The impact of this coupling on the total dynamic response of the structure can be quite severe depending on the similarity of the modal frequencies and shapes. Typically, acoustoelastic coupling is not a design feature, but rather an unintended result that must be remedied as modal tests of structures are often used to correlate or validate finite element models of the uncoupled structure. Here, however, a test structure is intentionally designed such that multiple structural and acoustic modes are well-aligned, resulting in… More >

Xi Liu, Xinjun Dong, Yang Wang^*, Jacob Dodson, Bryan Joyce

Sound & Vibration, Vol.52, No.3, pp. 6-11, 2018, DOI:10.32604/sv.2018.03857

Abstract This article reports the latest development of a wireless sensing system, named Martlet, on high-g shock acceleration measurement. The Martlet sensing node design is based on a Texas Instruments Piccolo microcontroller, with clock frequency programmable up to 90 MHz. The high clock frequency of the microcontroller enables Martlet to support high-frequency data acquisition and high-speed onboard computation. In addition, the extensible design of the Martlet node conveniently allows incorporation of multiple sensor boards. In this study, a high-g accelerometer interface board is developed to allow Martlet to work with the selected microelectromechanical system (MEMS) high-g accelerometers. Besides low-pass and high-pass… More >

Matthew Muirhead, Iswandaru Widyatmoko

Sound & Vibration, Vol.52, No.3, pp. 2-5, 2018, DOI:10.32604/sv.2018.03846

Abstract Road traffic noise can have a significant impact on the quality of life for residents close to major road networks. One of the most effective measures for reducing the noise from road traffic, particularly on high-speed roads, is to ensure the use of a low noise road surface. Research on pavement construction and the measurement of its acoustic properties has shown that significant noise reductions can be achieved through the use of certain road surface types. However certain low noise road surfaces do not exhibit the desired durability associated with more traditional pavements, leading to costly and disruptive maintenance regimes.
… More >

Jinshan Lin^a*, Chunhong Dou^b, Qianqian Wang^a

Sound & Vibration, Vol.52, No.2, pp. 11-15, 2018, DOI:10.32604/sv.2018.03653

Abstract A method for gearbox fault diagnosis consists of feature extraction and fault identification. Many methods for feature extraction have been devised for exposing nature of vibration data of a defective gearbox. In addition, features extracted from gearbox vibration data are identified by various classifiers. However, existing literatures leave much to be desired in assessing performance of different combinatorial methods for gearbox fault diagnosis. To this end, this paper evaluated performance of several typical combinatorial methods for gearbox fault diagnosis by associating each of multifractal detrended fluctuation analysis (MFDFA), empirical mode decomposition (EMD) and wavelet transform (WT) with each of neural… More >

Claude Prost, Bruno Abdelnour

Sound & Vibration, Vol.52, No.2, pp. 7-10, 2018, DOI:10.32604/sv.2018.03641

Abstract Wire Rope Isolators (WRI) are well known and used for the protection of sensitive equipment against non-contact underwater explosions (UNDEX) on board Naval Ships, amongst others, which are extremely destructive and can comple`tely impair the ship’s combat capability.
Traditional WRI exhibit a number of definite advantages, such as large deflection capability, modularity and insensitivity to aggressive environment when proper materials are used. However, their inherent nonlinearity does not always provide the best solution in terms of shock attenuation. (Stiffening tension characteristics)
Fortunately, there are ways to overcome this problem, namely increasing their damping and/ or changing their aspect ratio. It… More >

Brian Schwarz, Patrick McHargue, Mark Richardson

Sound & Vibration, Vol.52, No.2, pp. 1-6, 2018, DOI:10.32604/sv.2018.03637

Abstract In this paper, we show how Operating Deflection Shapes (ODS’s) and mode shapes can be obtained experimentally from measurements that are made using only two sensors and two short wires to connect them to a multi-channel acquisition system. This new test procedure is depicted in Figure 1. Not only is the equipment required to do a test much more cost effective, but this method can be used to test any sized test article, especially large ones.
The testing method introduced here involves moving a pair of sensors along together in a prescribed manor, and calculating the Transmissibility between them. The… More >

David E. Soine, Richard J. Jones, Jr., Julie M. Harvie, Troy J. Skousen, Tyler F. Schoenherr

Sound & Vibration, Vol.52, No.1, pp. 9-12, 2018, DOI:10.32604/sv.2018.03629

Abstract Qualification of products to their vibration and shock requirements in a laboratory setting consists of two basic steps. The first is the quantification of the product’s mechanical environment in the field. The second is the process of testing the product in the laboratory to ensure it is robust enough to survive the field environment. The latter part is the subject of the “Boundary Condition for Component Qualification” challenge problem. This paper describes the challenges in determining the appropriate boundary conditions and input stimulus required to qualify the product. This paper also describes the step sand analyses that were taken to… More >

Julie Harvie, Peter Avitabile

Sound & Vibration, Vol.52, No.1, pp. 3-7, 2018, DOI:10.32604/sv.2018.03618

Abstract Impedance modeling is often utilized to generate frequency response functions of an assembled system using modal characteristics of individual components. Sometimes slight inaccuracies are manifested in the characteristics of the components. Although those inaccuracies may seem minor in regards to the component for a traditional modal model, the inaccuracies can be amplified when impedance modeling is performed. Frequency based substructuring involves inversion of the frequency response functions and therefore requires considerable accuracy for the measurement, particularly in the area of anti-resonances.
For this study, some aspects of frequency based substructuring were explored, namely difficulties that might be encountered in experimental… More >

Raj Singh

Sound & Vibration, Vol.52, No.1, pp. 1-1, 2018, DOI:10.32604/sv.2018.03601

Abstract This article has no abstract. More >