Research Publications

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    Low-Cost, High-Precision Vibration Analysis: Enhancing SHM and Seismic Data Acquisition Systems
    (Institute of Electrical and Electronics Engineers Inc., 2025) Sashik, D; Iddamalgoda, A; Manchanayake, N; Prasanna, R; Abeygunawardhana, P.K.W
    The development of a low-frequency vibration detection device is essential for testing vibrations in crucial applications such as structural integrity, seismic activity detection and industrial machinery maintenance. Current data acquisition systems suffer from lack of sensitivity and high cost. This paper presents the design and development of a low-cost vibration detection device that uses a 3-axis accelerometer and a geophone with a resonant frequency of 4.5 Hz, where the signals are filtered using a second order low-pass filter with a 250 Hz cutoff frequency. The device is integrated with a 24-bit analog to digital (ADC) converter for ensuring a precise data acquisition and the device ensures to monitor real-time vibrations of x, y and z axis using a accelerometer and the z axis with a geophone. The effectiveness of the device was validated via experimental simulations. This developed device is a solid and cost-effective solution for engineers and professionals, where reliable low-frequency vibration monitoring is required in critical applications.
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    Vertical vibrations of an elastic foundation with arbitrary embedment within a transversely isotropic, layered soil
    (Elsevier, 2014) Labaki, J; Mesquita, E; Rajapakse, R. K. N. D
    Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the twophased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions for a transversely isotropic poroelastic soil half-space under a buried time-harmonic vertical load and a time-harmonic pore pressure discontinuity. These versatile fundamental solutions are derived by using Hankel integral transforms. They can be used to analyze a variety of dynamic problems in geomechanics. The fundamental solutions are then applied to solve the timeharmonic vertical vibration of a flexible circular foundation by using variational methods. Selected numerical results are presented to demonstrate the influence of soil anisotropy, poroelasticity, foundation flexibility, depth of embedment and frequency of excitation on the vertical dynamic response of foundation and the force transmitted to soil.
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    Vertical vibration of a circular foundation in a transversely isotropic poroelastic soil
    (Elsevier, 2020-05-01) Senjuntichai, T; Keawsawasvong, S; Rajapakse, R. K. N. D
    Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the two-phased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions for a transversely isotropic poroelastic soil half-space under a buried time-harmonic vertical load and a time-harmonic pore pressure discontinuity. These versatile fundamental solutions are derived by using Hankel integral transforms. They can be used to analyze a variety of dynamic problems in geomechanics. The fundamental solutions are then applied to solve the time-harmonic vertical vibration of a flexible circular foundation by using variational methods. Selected numerical results are presented to demonstrate the influence of soil anisotropy, poroelasticity, foundation flexibility, depth of embedment and frequency of excitation on the vertical dynamic response of foundation and the force transmitted to soil.