Development of a Porcine Thigh Finite Element Model for Evaluating the Soft-Tissue Injuries Caused by Blunt Impacts during Human-Robot Interactions**This research was conducted as a part of the project of ‘The International Standardization on Measurement Methods of Skin Injury Tolerance for Next-generation Safety of Machinery in Human-machine Interaction’ by the Ministry of Economy, Trade, and Industry of Japan

Author(s):  
Yu-ki Higuchi ◽  
Tatsuo Fujikawa ◽  
Ryuji Sugiura ◽  
Tetsuya Nishimoto ◽  
Fusako Sato
2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.


2011 ◽  
Vol 66-68 ◽  
pp. 983-988
Author(s):  
M. Liu ◽  
Q.H. Zhang ◽  
L.Y. Gao ◽  
Xue Mei Qin

Needle biopsy is a widely used medical procedure in which a tissue sample is cut and removed by needle for examination to identify and diagnose cancer and other diseases. Predictions of soft tissue deformation and reaction caused by needle insertion are important for the accuracy of this procedure. In this paper, in order to aquire the properties of soft tissue, indentation experiments of porcine livers are performed as non-invasive test to measure the force response depending on time in various indentation depth and indentation velocities conditions. A nonlinear least square method on Matlab have been created to fit the indentation results. According to the experimental and fitting indentation force-time curves, the coefficients of Neo-Hookean model and Kelvin model which are selected to develop the nonlinear model of porcine liver are acquired . Finally, a finite element model of liver based on experimental data is finally developed and succeeds in simulating the stress relaxation character and force-time curve. This finite element model and methodology can be used to investigate soft tissue reaction in needle biopsy.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Murong Li ◽  
Dedong Gao ◽  
Yong Lei ◽  
Tian Xu

This paper presents a novel dynamic path planning methodology for needle steering into the soft tissue. A real-time finite element model is used to simulate the procedure of a flexible needle into the homogeneous soft tissue, which provides the dynamic deformation information for the path planning. The relationship between needle base and tip is formulated as the transformations of homogeneous matrix with quasi-static assumptions. Based on the reachability of the flexible needle, the real-time motions of obstacles and target are considered through the dynamic needle-tissue interactions. A testbed including a XY linear stage, one rotator, and a CCD camera is constructed, and the experiments are designed to validate the proposed method. The 23G PTC needle was inserted into the PVA phantom with markers, and the CCD camera was utilized to record the needle trajectories and motions of target and obstacles. The targeting errors between the experimental and planned paths are less than 1.20 mm, and the distance from the obstacle to needle is not smaller than 1.16 mm. The results demonstrate that the proposed algorithm is effective for online planning the paths in the needle-tissue interactive environment.


1992 ◽  
Vol 34 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Mitsuru MOTOYOSHI ◽  
Shigemi YAMAMURA ◽  
Akira NAKAJIMA ◽  
Akihiko YOSHIZUMI ◽  
Yoshinari UMEMURA ◽  
...  

Author(s):  
Serhan Acikgoz ◽  
Thomas J. Royston ◽  
Hansen A. Mansy ◽  
Richard H. Sandler

A mechanical phantom model was built to simulate percussive techniques for diagnosing pneumothorax (PTX) and hydrothorax (HTX) (collapsed lung with air or water in the pleural space, respectively). The model was built with materials that have similar acoustic properties to that of human parenchyma, soft tissue and ribs. A bladder was embedded into the parenchyma-mimicking foam to simulate PTX or HTX. Experimental frequency response measurements were taken on the mechanical phantom model for the simulated pathologies and the healthy case with percussive excitation and noninvasive response measurements at the soft tissue surface. To aid in understanding experimental measurements, a finite element model of the experimental setup was constructed in ANSYS and used to simulate these same cases. Normal velocity amplitudes over the soft tissue surface measured from the experimental setup and calculated via the finite element model were analyzed in the frequency domain to identify any patterns or signatures that could be exploited for diagnosis. Experiment and numerical studies agree in identifying the key features of the PTX condition versus the healthy case, but differ somewhat on how HTX can be distinguished from PTX and the healthy case. Reasons for this discrepancy are discussed. With some improvements, these computational and experimental phantom models may aid in the development of improved noninvasive acoustic techniques for identifying these and other life-threatening conditions.


2020 ◽  
Vol 48 (6) ◽  
pp. 030006052092640
Author(s):  
Hongming Xu ◽  
Jiali Chen ◽  
Shilei Pu ◽  
Xiaoyan Li

This study was performed to investigate the feasibility of using a three-dimensional (3D) finite element model for laryngomalacia severity assessment. We analyzed laryngeal computed tomography images of seven children with laryngomalacia using Mimics software. The gray threshold of different tissues was distinguishable, and a 3D visualization model and finite element model were constructed. The laryngeal structure parameters were defined. The peak von Mises stress (PVMS) value was obtained through laryngeal mechanical analysis. The PVMS values of the laryngeal soft tissue and cartilage scaffolds were independently correlated with disease severity. After stress loading the model, the relationship between laryngomalacia severity and the PVMS value was apparent. However, the PVMS value of laryngeal soft tissue was not correlated with laryngomalacia severity. This study established the efficacy of a finite element model to illustrate the morphological features of the laryngeal cavity in infants with laryngomalacia. However, further study is required before widespread application of 3D finite element modeling of laryngomalacia. PVMS values of the laryngeal cartilage scaffold might be useful for assessment of laryngomalacia severity. These findings support the notion that structural abnormalities of the laryngeal cartilage may manifest as quantifiable changes in stress variants of the supraglottic larynx.


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