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Silva METD, Pinheiro FAT, Ferreira NM, Brandão FSQDS, Martins PALDS, Parente MPL, Mascarenhas Saraiva MTDQEC, Fernandes AA, Natal Jorge RM. An estimation of the biomechanical properties of the continent and incontinent woman bladder via inverse finite element analysis. Proc Inst Mech Eng H 2024:9544119241237356. [PMID: 38523483 DOI: 10.1177/09544119241237356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Stress urinary incontinence often results from pelvic support structures' weakening or damage. This dysfunction is related to direct injury of the pelvic organ's muscular, ligamentous or connective tissue structures due to aging, vaginal delivery or increase of the intra-abdominal pressure, for example, defecation or due to obesity. Mechanical changes alter the soft tissues' microstructural composition and therefore may affect their biomechanical properties. This study focuses on adapting an inverse finite element analysis to estimate the in vivo bladder's biomechanical properties of two groups of women (continent group (G1) and incontinent group (G2)). These properties were estimated based on MRI, by comparing measurement of the bladder neck's displacements during dynamic MRI acquired in Valsalva maneuver with the results from inverse analysis. For G2, the intra-abdominal pressure was adjusted after applying a 95% impairment to the supporting structures. The material parameters were estimated for the two groups using the Ogden hyperelastic constitutive model. Finite element analysis results showed that the bladder tissue of women with stress urinary incontinence have the highest stiffness (α1 = 0.202 MPa and µ1 = 7.720 MPa) approximately 47% higher when compared to continent women. According to the bladder neck's supero-inferior displacement measured in the MRI, the intra-abdominal pressure values were adjusted for the G2, presenting a difference of 20% (4.0 kPa for G1 and 5.0 kPa for G2). The knowledge of the pelvic structures' biomechanical properties, through this non-invasive methodology, can be crucial in the choice of the synthetic mesh to treat dysfunction when considering personalized options.
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Affiliation(s)
| | | | | | - Fernanda Sofia Quintela da Silva Brandão
- CESPU, Vale do Ave Higher School of Health, Department of Diagnostic and Therapeutic Technologies, Polytechnic Health Institute of North, Porto, Portugal
- H2M - Health and Human Movement Research Unit, Department of Diagnostic and Therapeutic Technologies, Vale do Ave Higher School of Health, Polytechnic Health Institute of North, Porto, Portugal
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2
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Yang M, Chen C, Wang Z, Long J, Huang R, Qi W, Shi R. Finite element analysis of female pelvic organ prolapse mechanism: current landscape and future opportunities. Front Med (Lausanne) 2024; 11:1342645. [PMID: 38323034 PMCID: PMC10844411 DOI: 10.3389/fmed.2024.1342645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/05/2024] [Indexed: 02/08/2024] Open
Abstract
The prevalence of pelvic organ prolapse (POP) has been steadily increasing over the years, rendering it a pressing global health concern that significantly impacts women's physical and mental wellbeing as well as their overall quality of life. With the advancement of three-dimensional reconstruction and computer simulation techniques for pelvic floor structures, research on POP has progressively shifted toward a biomechanical focus. Finite element (FE) analysis is an established tool to analyze the biomechanics of complex systems. With the advancement of computer technology, an increasing number of researchers are now employing FE analysis to investigate the pathogenesis of POP in women. There is a considerable number of research on the female pelvic FE analysis and to date there has been less review of this technique. In this review article, we summarized the current research status of FE analysis in various types of POP diseases and provided a detailed explanation of the issues and future development in pelvic floor disorders. Currently, the application of FE analysis in POP is still in its exploratory stage and has inherent limitations. Through continuous development and optimization of various technologies, this technique can be employed with greater accuracy to depict the true functional state of the pelvic floor, thereby enhancing the supplementation of the POP mechanism from the perspective of computer biomechanics.
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Affiliation(s)
- Miyang Yang
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Chujie Chen
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Zhaochu Wang
- Department of Anorectal, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Jiaye Long
- Department of Interventional Radiology, Inner Mongolia Forestry General Hospital, The Second Clinical Medical School of Inner Mongolia University for The Nationalities, Yakeshi, China
| | - Runyu Huang
- The First Clinical Medical College, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Wan Qi
- Department of Radiology, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
| | - Rong Shi
- Department of Anorectal, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
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3
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Xue X, Wang H, Xie J, Gao Z, Shen J, Yao T. Two-dimensional biomechanical finite element modeling of the pelvic floor and prolapse. Biomech Model Mechanobiol 2023:10.1007/s10237-023-01729-y. [PMID: 37294482 DOI: 10.1007/s10237-023-01729-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/20/2023] [Indexed: 06/10/2023]
Abstract
We developed the pelvic floor model in physiological and pathological states to understand the changes of biomechanical axis and support that may occur from the normal physiological state to the prolapse pathological state of the pelvic floor. Based on the physiological state model of the pelvic floor, we model the uterus to the pathological state position by balancing intra-abdominal pressure (IAP) and uterine pathological position load. Under combined impairments, we compared the patterns of changes in pelvic floor biomechanics that may be induced by different uterine morphological characteristic positions under different IAP. The orientation of the uterine orifice gradually changes from the sacrococcygeal direction to the vertical downward of vaginal orifice, and a large downward prolapse displacement occurs, and the posterior vaginal wall shows "kneeling" profile with posterior wall bulging prolapse. When the abdominal pressure value was 148.1 cmH2O, the descent displacement of the cervix in the normal and pathological pelvic floor system was 11.94, 20, 21.83 and 19.06 mm in the healthy state, and 13.63, 21.67, 22.94 and 19.38 mm in the combined impairment, respectively. The above suggests a maximum cervical descent displacement of the uterus in the anomalous 90° position, with possible cervical-uterine prolapse as well as prolapse of the posterior vaginal wall. The combined forces of the pelvic floor point in the direction of vertical downward prolapse of the vaginal orifice, and the biomechanical support of the bladder and sacrococcygeal bone gradually diminishes, which may exacerbate the soft tissue impairments and biomechanical imbalances of the pelvic floor to occur of POP disease.
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Affiliation(s)
- Xianglu Xue
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China
| | - Haifeng Wang
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Jiachen Xie
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China
| | - Zhenhua Gao
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Jihong Shen
- The First Department of Urology, The First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Kunming, 650032, China
| | - Tingqiang Yao
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, No.727, Jingming South Road, Chenggong District, Kunming, 650500, China.
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4
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Xie J, Li S, Yao T, Shen J. A 2D equivalent mechanical model of the whole pelvic floor and impairment simulation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3659. [PMID: 36305715 DOI: 10.1002/cnm.3659] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
We developed a complete 2D equivalent mechanical model of the pelvic floor based on magnetic resonance imaging (MRI) images of a 35-year-old healthy woman. This model can simulate anterior vaginal prolapse (AVP) due to soft tissue impairment. Thus, we can study the mechanism of prolapse formation from a mechanical perspective and improve the assessment and treatment of the condition in clinical practice. Based on 2D MRI image parameter measurements and computer-aided design methods, the 2D equivalent mechanical model of the whole pelvic floor in the sagittal plane was accurately reconstructed, which includes all necessary tissues of the pelvic floor system. Material parameters were mainly from the literature. We simulated the impairment by reducing the tissue's mechanical properties, and numerical simulations predicted the mechanical response and morphological changes of the healthy and impaired pelvic floor in different states. In six intra-abdominal pressure (IAP) states (8.4-208.9 cmH2 O), the maximum cervical descent in the impaired pelvic floor was 0.3-18.521 mm, which was much greater than that in the healthy pelvic floor (0.14-6.55 mm). Once the impairment occurred (0%-25%), there was a significant increase in maximum displacement, stress, and cervical descent (30.9-36.5 mm, 0.56-1.12 MPa, 4.6-12.1 mm), and a clinically similar prolapse shape occurred. Simple supine and standing will not cause prolapse. The formation of prolapse is closely related to vaginal tissue impairment. In the standing position, the main forces on the healthy pelvic floor system are distributed horizontally posteriorly and inferiorly, reducing the burden in the vertically downward direction.
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Affiliation(s)
- Jiachen Xie
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Song Li
- Department of Urology, First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Tingqiang Yao
- Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, China
| | - Jihong Shen
- Department of Urology, First Affiliated Hospital of Kunming Medical University, Kunming, China
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5
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Silva METD, Bessa JNM, Rynkevic R, Parente MPL, Saraiva MTDQECM, Natal Jorge RM, Fernandes AA. Simulation of vaginal uterosacral ligament suspension damage, mimicking a mesh-augmented apical prolapse repair. Proc Inst Mech Eng H 2022; 236:9544119221074567. [PMID: 35088624 DOI: 10.1177/09544119221074567] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Synthetic implants were used for repair of anterior compartment prolapses, which can be caused by direct trauma resulting in damaged pelvic structures. The mechanical properties of these implants may cause complications, namely erosion of the mesh through the vagina. In this study, we evaluated, by modeling, the behavior of implants, during Valsalva maneuver, used to replace damaged uterosacral ligaments (USLs), mimicking a sacrocolpopexy repair. For this purpose, two synthetic implants (A®, for prolapse repair and B®, for Hernia repair) were uniaxially tested, and the mechanical properties obtained were incorporated in the computational models of the implants. The computational model for the implant was incorporated into the model of the female pelvic cavity, in order to mimic the USLs after its total rupture and with 90% and 50% impairment. The total rupture and impairments of the USLs, caused a variation of the supero-inferior displacement and displacement magnitude of the vagina, with higher values for the total rupture. With total rupture of the USLs, when compared to healthy USLs, supero-inferior displacement and displacement magnitude of the vagina increased by 4.98 mm (7.69 mm vs 12.67 mm) and 6.62 mm (9.38 mm vs 16.00 mm), respectively. After implantation (A® and B®) a reduction of the supero-inferior displacements of the anterior vaginal wall occurred, to values found in the case of the model without any impairment or rupture of the ligaments. The simulation was able to mimic the biomechanical response of the USLs, in response to different implants stiffnesses, which can be used in the development of novel meshes.
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Affiliation(s)
| | | | - Rita Rynkevic
- LAETA, INEGI, Faculty of Engineering, University of Porto, Porto, Portugal
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6
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Diallo MN, Mayeur O, Lecomte-Grosbras P, Patrouix L, Witz JF, Lesaffre F, Rubod C, Cosson M, Brieu M. Simulation of the mobility of the pelvic system: influence of fascia between organs. Comput Methods Biomech Biomed Engin 2021; 25:1073-1087. [PMID: 34783611 DOI: 10.1080/10255842.2021.2001460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The mobility of pelvic organs is the result of an equilibrium called Pelvic Static characterizing the balance between the properties and geometries of organs, suspensions and support system. Any imbalance in this complex system can cause of pelvic static disorder. Genital prolapse is a common hypermobility pathology which is complex, multi factorial and its surgical management has high rate of complications. The use of 3 D numerical models and simulation enables the role of the various suspension structures to be objectively studied and quantified. Fascias are connective tissues located between organs. Although their role are described as important in various descriptions of pelvic statics, their influence and role has never been quantitatively objectified. This article presents a refine Finite Element (FE) model for a better understanding of biomechanical contribution of inter-organ fascia. The model is built from MRI images of a young volunteer, the mechanical properties derived from literature data to take into account the age of the patient and new experimental results have enabled an order of magnitude of the mechanical properties of the fascias to be defined. The FE results allows to quantify the biomechanical role of the fascia on pelvic mobility quantified by an analysis of dynamic MRI images and a local mapping of the gap between calculated and measured displacements. This improved numerical model integrating the fascias makes it possible to describe pelvic mobilities with a gap of 1 mm between numerical simulations and measurements, whereas without taking them into account this gap locally reaches 20 mm.
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Affiliation(s)
- Mouhamadou Nassirou Diallo
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - Olivier Mayeur
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - Pauline Lecomte-Grosbras
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - Laurent Patrouix
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - Jean François Witz
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - François Lesaffre
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France
| | - Chrystle Rubod
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France.,Service de chirurgie gynécologique - CHU Lille, Lille, France
| | - Michel Cosson
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France.,Service de chirurgie gynécologique - CHU Lille, Lille, France
| | - Mathias Brieu
- CNRS, Centrale Lille, UMR 9013 - LaMcube - Laboratoire de Mécanique, Multiphysique, Multiéchelle, University of Lille, Lille, France.,Department of Mechanical Engineering, College Engineering, Computer Science and Technology, California State University, Los Angeles, Long Angeles, CA, USA
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7
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Tawara D, Nishiki T, Ninomiya S, Okayama H, Naito K, Morikawa S. Development of primary design guidelines for supportive underwear to elevate the bladder neck in women based on finite element analysis of the pelvis. Proc Inst Mech Eng H 2021; 236:269-278. [PMID: 34546113 DOI: 10.1177/09544119211047058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The use of supportive underwear has been applied for preventing stress urinary incontinence (SUI) which is caused by descent of the bladder neck due to weakness in the pelvic floor muscles, because it is known that SUI can be improved by elevating the descended bladder neck. However, appropriate approaches to the underwear design are still being explored. In order to establish an appropriate first-order design strategy for supportive underwear, clarifying the relationship between the pressure from the underwear and the amount of elevation of the bladder neck is necessary. We constructed a finite element model of the pelvis based on magnetic resonance images of a subject in an upright position, experimentally explored Young's modulus of the soft tissue and analyzed the amount of elevation of the bladder neck when changing the combination of applied pressures from the underwear. The position of the bladder neck relatively elevated when the pressure in the region from the abdomen to the pubis decreased and when the pressure in the region from the perineum to the coccyx increased, suggesting an appropriate design for the supportive underwear.
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Affiliation(s)
- Daisuke Tawara
- Department of Mechanical Engineering and Robotics, Ryukoku University, Otsu, Shiga, Japan
| | - Tomohiro Nishiki
- Medical Equipment Division, Engineering Department, Shiga Equipment Factory, TAKARA BELMONT Corp., Konan, Shiga, Japan
| | - Sanae Ninomiya
- Faculty of Nursing, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan
| | - Hisayo Okayama
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kiyoko Naito
- Faculty of Education Welfare, Biwako-Gakuin University, Higashi-Omi, Shiga, Japan
| | - Shigehiro Morikawa
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga, Japan
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8
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Silva MET, Bessa JNM, Parente MPL, Mascarenhas T, Natal Jorge RM, Fernandes AA. Effect of mesh anchoring technique in uterine prolapse repair surgery: A finite element analysis. J Biomech 2021; 127:110649. [PMID: 34375905 DOI: 10.1016/j.jbiomech.2021.110649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/28/2021] [Accepted: 07/25/2021] [Indexed: 11/17/2022]
Abstract
The female pelvic cavity involves muscles, ligaments, endopelvic fasciae and multiple organs where different pathologies may occur, namely the pelvic organ prolapse (POP). The synthetic implants are used for the reconstructive surgery of POP, but severe complications associated with their use have been reported, mainly related to their mechanical properties (e.g., implant stiffness) and microstructure. In this study, we mimicked a transvaginal reconstructive surgery to repair the apical ligaments (uterosacral ligaments (USLs) and cardinal ligaments (CLs)), by modeling, their impairment (90% and 50%) and/or total rupture. The implants to reinforce/replace these ligaments were built based on literature specifications and their mechanical properties were obtained through uniaxial tensile tests. The main aim of this study was to simulate the effect of mesh anchoring technique (simple stich and continuous stitch), and compare the displacement magnitude of the pelvic tissues, during Valsalva maneuver. The absence/presence of the synthetic implant was simulated when total rupture of the CLs and USLs occurs, causing a variation of the vaginal displacement (9% for the CLs and 27% for the USLs). Additionally, the simulations showed that there was a variation of the supero-inferior displacement of the vaginal wall between different anchoring techniques (simple stich and continuous stitch) being approximately of 10% for the simulation USLs and CLs implant. The computational simulation was able to mimic the biomechanical behavior of the USLs and CLs, in response to different anchoring techniques, which can be help improving the outcomes of the prolapse surgery.
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Affiliation(s)
- M E T Silva
- LAETA, INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, Porto 4200 - 465, Portugal.
| | - J N M Bessa
- Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, Porto 4200 - 465, Portugal.
| | - M P L Parente
- LAETA, INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, Porto 4200 - 465, Portugal.
| | - T Mascarenhas
- Dep. of Obstetrics and Gynecology, CHSJ-EPE / Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, Porto 4200 - 319, Portugal.
| | - R M Natal Jorge
- LAETA, INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, Porto 4200 - 465, Portugal.
| | - A A Fernandes
- LAETA, INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, Porto 4200 - 465, Portugal.
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9
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Li Y, Sang J, Wei X, Yu W, Tian W, Liu GR. Inverse identification of hyperelastic constitutive parameters of skeletal muscles via optimization of AI techniques. Comput Methods Biomech Biomed Engin 2021; 24:1647-1659. [PMID: 33787398 DOI: 10.1080/10255842.2021.1906235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Studies on the deformation characteristics and stress distribution in loaded skeletal muscles are of increasing importance. Reliable prediction of hyperelastic material parameters requires an inverse process, which possesses challenges. This work proposes two inverse procedures to identify the hyperelastic material parameters of skeletal muscles. The first one integrates nonlinear finite element method (FEM), random forest (RF) model, and Bayesian optimization (BO) algorithm. The other one integrates FEM, RF and hybrid Grid Search (GS), and Random Search (RS) algorithm. FEM models are first established to simulate nonlinear deformation of skeletal muscles subject to compression based on nonlinear mechanics principals. A dataset of nonlinear relationship between the nominal stress and principal stretch of skeletal muscles is created using our FEM models and the nonlinear relationship is learned through RF model. The BO, hybrid GS and RS algorithms are used to adjust the major model parameters in RF. Then the optimized RF is utilized to predict hyperelastic material parameters of skeletal muscles, with the help of uniaxial compression experiments. Intensive studies also have been carried out to compare the RF-BO approach with RF-Search approach, and the comparison results show that RF-BO approach is an effective and accurate approach to identify the hyperelastic material parameters of skeletal muscles. The present RF-BO model can be further extended for the predictions of constitutive parameters of other types of nonlinear soft materials.
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Affiliation(s)
- Yang Li
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, P.R. China
| | - Jianbing Sang
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, P.R. China
| | - Xinyu Wei
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, P.R. China
| | - Wenying Yu
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, P.R. China
| | - Weichang Tian
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, P.R. China
| | - G R Liu
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio, USA
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