Archive

A CHEBYSHEV SPECTRAL COLLOCATION FRAMEWORK FOR GUIDED WAVES IN FLUID-LOADED CORTICAL BONE: EFFECTS OF ANISOTROPY AND POROSITY

Authors:

M. S. L. R. Mallika, G. Sudheer, N. Aparna

DOI NO:

https://doi.org/10.26782/jmcms.2026.08.00014

Abstract:

Bone quantitative ultrasound (QUS) relies on the dispersion of guided waves propagating in the cortical shell of long bones. Analytical fluid–solid–fluid trilayer models obtain the dispersion relation from a characteristic determinant whose roots must be located numerically, a procedure that becomes delicate near mode osculations and for anisotropic cortical bone. Here the fluid–solid–fluid waveguide is reformulated as a linear generalized eigenvalue problem using a Chebyshev spectral-collocation method. Each layer is discretized on a Chebyshev–Gauss–Lobatto grid, and the interface and free-surface conditions are imposed directly by row replacement. For a prescribed wavenumber, the eigenvalue is W = ω², so every finite discrete eigenmode follows from a single generalized eigensolve without determinant root searching; the physical guided branches are then selected by explicit admissibility and participation criteria. The method is validated against an independently implemented analytical global-matrix solver for a water/aluminum/water trilayer: the fundamental extensional (S₀) and flexural (A₀) phase velocities agree within numerical tolerance (better than 10⁻⁵ %), and a convergence study with eigen-residual norms confirms spectral accuracy at about fourteen collocation nodes per layer. The same framework is then extended to a transversely isotropic cortical-bone layer and, with one additional volume-fraction field, to a linear elastic material with voids. Transverse isotropy raises the low-frequency extensional plateau by about 8.2 %, whereas increasing void coupling lowers it by up to 15 %. A Hellmann–Feynman sensitivity analysis shows that this plateau constrains only one stiffness combination, so these figures are forward-model discrepancies rather than uniquely recoverable inverse biases.

Keywords:

guided waves; cortical bone; quantitative ultrasound; spectral collocation; transverse isotropy; elastic materials with voids,

References:

I. J. D. Achenbach, Wave Propagation in Elastic Solids, North-Holland, Amsterdam (1973).
II. A. T. I. Adamou, R. V. Craster, Spectral methods for modelling guided waves in elastic media, Journal of the Acoustical Society of America 116(3) (2004) 1524–1535. 10.1121/1.1777871
III. U. Andreaus, I. Giorgio, A. Madeo, Modeling of the interaction between bone tissue and resorbable biomaterial as linear elastic materials with voids, Zeitschrift für angewandte Mathematik und Physik (ZAMP) 66(1) (2015) 209–237. 10.1007/s00033-014-0403-z
IV. N. Bochud, Q. Vallet, Y. Bala, H. Follet, J.-G. Minonzio, P. Laugier, Genetic algorithms-based inversion of multimode guided waves for cortical bone characterization, Physics in Medicine and Biology 61(19) (2016) 6953–6974. 10.1088/0031-9155/61/19/6953
V. A. Chaboty, V.-H. Nguyen, G. Haïat, P. Bélanger, Cortical bone plate properties assessment using inversion of axially transmitted low-frequency ultrasonic guided waves, Journal of the Acoustical Society of America 156(2) (2024) 954–967. 10.1121/10.0028173
VI. S. C. Cowin, J. W. Nunziato, Linear elastic materials with voids, Journal of Elasticity 13(2) (1983) 125–147. 10.1007/BF00041230
VII. M. A. Denolle, E. M. Dunham, G. C. Beroza, Solving the surface-wave eigenproblem with Chebyshev spectral collocation, Bulletin of the Seismological Society of America 102(3) (2012) 1214–1223. 10.1785/0120110183
VIII. M. A. Goodman, S. C. Cowin, A continuum theory for granular materials, Archive for Rational Mechanics and Analysis 44(4) (1972) 249–266. 10.1007/BF00284326
IX. M. Granke, Q. Grimal, A. Saïed, P. Nauleau, F. Peyrin, P. Laugier, Change in porosity is the major determinant of the variation of cortical bone elasticity at the millimeter scale in aged women, Bone 49(5) (2011) 1020–1026. 10.1016/j.bone.2011.08.002
X. F. Hernando Quintanilla, Z. Fan, M. J. S. Lowe, R. V. Craster, Guided waves’ dispersion curves in anisotropic viscoelastic single- and multi-layered media, Proceedings of the Royal Society A 471(2183) (2015) 20150268. 10.1098/rspa.2015.0268
XI. D. A. Kiefer, G. Watzl, K. Burgholzer, M. Ryzy, C. Grünsteidl, Electroelastic guided wave dispersion in piezoelectric plates: spectral methods and laser-ultrasound experiments, Journal of Applied Physics 137(11) (2025) 114502. 10.1063/5.0250494
XII. P. Laugier, G. Haïat (eds.), Bone Quantitative Ultrasound, Springer (2010). 10.1007/978-94-007-0017-8
XIII. L. H. Le, V.-H. Nguyen, T. N. H. T. Tran, Ultrasonic guided waves in bone: a decade of advancement in review, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 69(9) (2022) 2540–2557.
XIV. J.-G. Minonzio, N. Bochud, Q. Vallet, Y. Bala, D. Ramiandrisoa, H. Follet, D. Mitton, P. Laugier, Bone cortical thickness and porosity assessment using ultrasound guided waves: an ex vivo validation study, Bone 116 (2018) 111–119. 10.1016/j.bone.2018.07.018
XV. H. Nguyen, D. Le, E. Plan, S. T. Dang, H. Phan, Theoretical model of guided waves in a bone-mimicking plate coupled with soft-tissue layers, Vietnam Journal of Mechanics 43(1) (2021) 91–104. 10.15625/0866-7136/15774
XVI. V.-H. Nguyen, T. N. H. T. Tran, M. D. Sacchi, S. Naili, L. H. Le, Computing dispersion curves of elastic/viscoelastic transversely-isotropic bone plates coupled with soft tissue and marrow using a semi-analytical finite element (SAFE) method, Computers in Biology and Medicine 87 (2017) 371–381. 10.1016/j.compbiomed.2017.06.001
XVII. J. W. Nunziato, S. C. Cowin, A nonlinear theory of elastic materials with voids, Archive for Rational Mechanics and Analysis 72(2) (1979) 175–201. 10.1007/BF00249363
XVIII. J. L. Rose, Ultrasonic Guided Waves in Solid Media, Cambridge University Press (2014).
XIX. L. N. Trefethen, Spectral Methods in MATLAB, SIAM, Philadelphia (2000). 10.1137/1.9780898719598
XX. J. A. C. Weideman, S. C. Reddy, A MATLAB differentiation matrix suite, ACM Transactions on Mathematical Software 26(4) (2000) 465–519. 10.1145/365723.365727

View Download

STOCHASTIC ANALYSIS OF A SINGLE UNIT SYSTEM WITH VARYING DEMAND AND MINOR-MAJOR FAILURES

Authors:

Rishu Wadhwa, Reetu Malhotra

DOI NO:

https://doi.org/10.26782/jmcms.2026.08.00014

Abstract:

With the rapid increase of the societal requirements and the complexity of the industrial systems there is a great need to achieve high reliability without losing profitability. Small system failures might lead to huge loss of operational activities, downtimes and low productivity. In this paper, the authors propose a stochastic reliability model to analyze the availability and profitability of an industrial system under environmental factors and fluctuating demand. The proposed model assumes that it is a single unit system where there are no failures that can be tolerated. It is also equipped with an inspection mechanism to identify the kind of failure occurring in the system. The failures are called minor and major failures.Minor failures are caused by lubrication or greasing problems which can be repaired and major failures are caused by electrical short circuiting, water ingestion in the time of adverse weather and overloading as well as prolonged continuous operation . In case of major failures the system is either repaired or replaced depending upon the extent of damage. The two operating cases are studied where the demand is higher than or equal to the production and the demand is lower than the production. The regenerative point technique and Semi-Markov processes are used to evaluate key performance measures and profit thoroughly with respect to the effects of different parameters of the system.Data has been collected from a steel manufacturing plant, Rajpura, Punjab, India.The outcomes are very informative for the visited plant and provide suggestions for best management of inspection, maintenance, and operational strategies.

Keywords:

Reliability,Inspection,Variation in demand,Regenerative point technique,Semi-Markov process,Innovation.,

References:

I. Agnihotri, R. K., Ajit Khare, and Sanjay Jain. "Reliability analysis of a system of boiler used in readymade garment industry." Journal of Reliability and Statistical Studies (2008): 33-41, ISSN: 2229-5666
II. Balagurusamy, E. "Reliability Engineering. Tata McGraw-Hill Education." (1984), ISBN-10: 0070483396.
III. Behboudi, Zohreh, GR Mohtashami Borzadaran, and Majid Asadi. "Reliability modeling of two-unit cold standby systems: a periodic switching approach." Applied Mathematical Modelling 92 (2021), doi:176-195. 10.1016/j.apm.2020.11.001
IV. Balaso, FarandeBahubali, and Hanumant P. Jagtap. "Failure analysis steam turbine in sugar factory thermal power plant: a Review." IOP conference series: earth and environmental science. Vol. 1285. No. 1. IOP Publishing, (2024), doi: 10.1088/1755-1315/1285/1/012005
V. Cassady, C. Richard, and Edward A. Pohl. "Introduction to repairable systems modeling." Annual reliability and maintainability symposium. Vol. 49. (2003).
VI. Davis, D. J. F. "An analysis of some failure data." Journal of the American Statistical Association 47.258 (1952): 113-150.
VII. doi: 10.1080/01621459.1952.10501160
VIII. Epstein, Benjamin, and Milton Sobel. "Sequential life tests in the exponential case." The Annals of Mathematical Statistics (1955): 82-93. doi: https://www.jstor.org/stable/2236758
IX. El-Said, Khaled M., and Mohamed Salah El-Sherbeny. "Profit analysis of a two unit cold standby system with preventive maintenance and random change in units."Journal of mathematics and statistics 1.1 (2005): 71-77. doi: 10.3844/jmssp.2005.71.77
X. Goel, L. R., Rakesh Gupta, and S. K. Singh. "Cost analysis of a two-unit cold standby system with two types of operation and repair." Microelectronics Reliability 25.1 (1985): 71-75, doi: 10.1016/0026-2714(85)90444-5
XI. Gupta, Rakesh, C. P. Bajaj, and S. M. Sinha. "A single server multi-component two-unit cold standby system with inspection and imperfect switching device." Microelectronics Reliability 26.5 (1986): 873-877, doi: 10.1016/0026-2714(86)90229-5
XII. Garg, Harish. "Performance analysis of complex repairable industrial systems using PSO and fuzzy confidence interval based methodology." ISA transactions 52.2 (2013), doi: 171-183. 10.1016/j.isatra.2012.09.010
XIII. Kumar, Janender, et al. "Reliability analysis in process industries–An overview." GIS Sci J 7.5 (2020): 151-168. ISSN NO : 1869-9391
XIV. Kaur, Harpreet, and Reetu Malhotra. "Profit Analysis of a System of Non-Identical Units with Varying Demand." Palestine Journal of Mathematics 14 (2025): 183, ISSN: 2219-5688.
XV. Mine, Hisashi, and Hajime Kawai. "Repair priority effect on availability of a 2-unit system." IEEE Transactions on Reliability 28.4 (1979): 325-326. doi: 10.1109/TR.1979.5220620.
XVI. Malhotra, Reetu, and Gulshan Taneja. "Reliability modelling of a cable manufacturing system with inspection and variation in demand." International Conference on Information and Mathematical Sciences. 2013, ISBN- 9789351071624
XVII. Malhotra, Reetu, and Gulshan Taneja. "Comparative study between a single unit system and a two-unit cold standby system with varying demand." Springerplus 4.1 (2015): 705, doi: 10.1186/s40064-015-1484-7.
XVIII. Mehta, Munish, Jujhar Singh, and Manpreet Singh. "Reliability analysis of sheet manufacturing unit of a steel industry." Advances in Industrial and Production Engineering: Select Proceedings of FLAME 2018. Singapore: Springer Singapore, 2019. 605-627, doi: 10.1007/978-981-13-6412-9_59
XIX. Malhotra, Reetu. "Reliability and availability analysis of a standby system with activation time and varying demand." Engineering reliability and risk assessment. Elsevier, 2023. 35-51, doi: 10.1016/B978-0-323-91943-2.00004-6
XX. Malhotra, Reetu, Faten S. Alamri, and HamidenAbd El-WahedKhalifa. "Novel analysis between two-unit hot and cold standby redundant systems with varied demand." Symmetry 15.6 (2023): 1220,
XXI. doi: 10.3390/sym15061220
XXII. Nakagawa, Toshio. "On a replacement problem of a cumulative damage model." Journal of the Operational Research Society 27.4 (1976): 895-900. doi: 10.1057/jors.1976.178
XXIII. Qian, Yibo, et al. "Greenhouse gas control in steel manufacturing: Inventory, assurance, and strategic reduction review." Carbon Research 3.1 (2024): 27. doi: 10.1007/s44246-024-00118-z
XXIV. Rizwan, S. M., Vipin Khurana, and Gulshan Taneja. "Reliability analysis of a hot standby industrial system." International Journal of Modelling and Simulation 30.3 (2010): 315-322, doi: 10.1080/02286203.2010.11442586
XXV. Rathi, Sardar Singh, M. Kumar Sahu, and Sanjeev Kumar. "Implementation of lean manufacturing methods to improve rolling mill productivity." International Journal of Advanced Technology and Engineering Exploration 11.111 (2024) 243-256,
XXVI. doi: 10.1080/02286203.2010.11442586
XXVII. Saini, Ashok, and Ashok Kumar. "Benefit analysis of a two-unit standby system subject to jerks with installation time." Microelectronics Reliability 36.3 (1996): 429-434, doi: 10.1016/0026-2714(95)00007-0
XXVIII. Saini, Sapna, Jitender Kumar, and Mukender Singh Kadyan. "Performance analysis of sinter system of steel plant using supplementary variable technique." International Journal of System Assurance Engineering and Management 15.7 (2024): 2931-2949, doi: 10.1007/s13198-024-02305-y
XXIX. Vanderperre, Edmond J. "Reliability analysis of a renewable multiple cold standby system." Operations Research Letters 32.3 (2004): 288-292, doi: 10.1016/j.orl.2003.10.002
XXX. Yousefi, Nooshin, StamatisTsianikas, and David W. Coit. "Reinforcement learning for dynamic condition-based maintenance of a system with individually repairable components." Quality Engineering 32.3 (2020): 388-408, doi: 10.1080/08982112.2020.1766692
XXXI. Yousuf, Muhammad Uzair, Muhammad Anus Irshad, and Muhammad Umair. "Identifying barriers and drivers for energy efficiency in steel and iron industries of Karachi, Pakistan: insights from executives and professionals."Energy Nexus 14 (2024): 100284.
XXXII. doi: 10.1016/j.nexus.2024.100284

View Download