scholarly journals Digital image correlation and finite element modelling as a method to determine mechanical properties of human soft tissue in vivo

2016 ◽  
Author(s):  
Kevin Mattheus Moerman
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Bulk Material ◽  
Constitutive Models ◽  
Image Correlation ◽  
Fe Model ◽  
Fe Modelling ◽  
Tissue Phantom ◽  
Human Soft Tissue

The mechanical properties of human soft tissue are crucial for impactbiomechanics, rehabilitation engineering and surgical simulation.Validation of these constitutive models using human data remainschallenging and often requires the use of non-invasive imaging and inversefinite element (FE) analysis. Post processing data from imaging methodssuch as tagged magnetic resonance imaging (MRI) can be challenging. DigitalImage Correlation (DIC) however is a relatively straightforward imagingmethod and thus the goal of this study was to assess the use of DIC incombination with FE modelling to determine the bulk material properties ofhuman soft tissue. Indentation experiments were performed on a silicone gelsoft tissue phantom. A two camera DIC setup was then used to record the 3Dsurface deformation. The experiment was then simulated using a FE model.

scholarly journals Concomitant control of mechanical properties and degradation in resorbable elastomer-like materials using stereochemistry and stoichiometry for soft tissue engineering

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mary Beth Wandel ◽  
Craig A. Bell ◽  
Jiayi Yu ◽  
Maria C. Arno ◽  
Nathan Z. Dreger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Soft Tissue ◽  
Tissue Regeneration ◽  
Biological Tissues ◽  
Soft Tissue Regeneration ◽  
Soft Tissue Engineering ◽  
Degradation Properties ◽  
Enhance Cell Adhesion

AbstractComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical, and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.

Reliability Investigation of Tissue Resonator Indenter Device

2010 ◽  
Author(s):  
Ming Jia ◽  
Jean W. Zu ◽  
Alireza Hariri
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Soft Tissues ◽  
Tissue Properties ◽  
University Of Toronto ◽  
In Vivo Measurements ◽  
Disease Diagnostics ◽  
Working Principle ◽  
The University

Knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for soft tissue properties in-vivo measurements, the reliability of TRID is crucial. This paper presents TRID’s working principle and the experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect as well. The experimental results show that TRID is a reliable device for in-vivo measurements of soft tissue mechanical properties.

scholarly journals Constrained Tibial Vibration in Mice: A Method for Studying the Effects of Vibrational Loading of Bone

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Blaine A. Christiansen ◽  
Philip V. Bayly ◽  
Matthew J. Silva
Keyword(s):  
Soft Tissue ◽  
Frequency Response ◽  
Natural Frequency ◽  
Lower Leg ◽  
Bone Strain ◽  
Fe Model ◽  
Loading Method ◽  
Vibrational Loading ◽  
Controlled Conditions

Vibrational loading can stimulate the formation of new trabecular bone or maintain bone mass. Studies investigating vibrational loading have often used whole-body vibration (WBV) as their loading method. However, WBV has limitations in small animal studies because transmissibility of vibration is dependent on posture. In this study, we propose constrained tibial vibration (CTV) as an experimental method for vibrational loading of mice under controlled conditions. In CTV, the lower leg of an anesthetized mouse is subjected to vertical vibrational loading while supporting a mass. The setup approximates a one degree-of-freedom vibrational system. Accelerometers were used to measure transmissibility of vibration through the lower leg in CTV at frequencies from 20Hzto150Hz. First, the frequency response of transmissibility was quantified in vivo, and dissections were performed to remove one component of the mouse leg (the knee joint, foot, or soft tissue) to investigate the contribution of each component to the frequency response of the intact leg. Next, a finite element (FE) model of a mouse tibia-fibula was used to estimate the deformation of the bone during CTV. Finally, strain gages were used to determine the dependence of bone strain on loading frequency. The in vivo mouse leg in the CTV system had a resonant frequency of 60Hz for ±0.5G vibration (1.0G peak to peak). Removing the foot caused the natural frequency of the system to shift from 60Hzto70Hz, removing the soft tissue caused no change in natural frequency, and removing the knee changed the natural frequency from 60Hzto90Hz. By using the FE model, maximum tensile and compressive strains during CTV were estimated to be on the cranial-medial and caudolateral surfaces of the tibia, respectively, and the peak transmissibility and peak cortical strain occurred at the same frequency. Strain gage data confirmed the relationship between peak transmissibility and peak bone strain indicated by the FE model, and showed that the maximum cyclic tibial strain during CTV of the intact leg was 330±82με and occurred at 60–70Hz. This study presents a comprehensive mechanical analysis of CTV, a loading method for studying vibrational loading under controlled conditions. This model will be used in future in vivo studies and will potentially become an important tool for understanding the response of bone to vibrational loading.

Dynamic instrumented palpation – a new method for soft tissue quality assessment: application to prostate disease diagnosis

2017 ◽  
Vol 231 (12) ◽  
pp. 1101-1115 ◽  
Author(s):  
TH Jimmy Yang ◽  
Simon Phipps ◽  
Steve KW Leung ◽  
Robert L Reuben ◽  
Fouad K Habib ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Mechanical Properties ◽  
Soft Tissue ◽  
Transurethral Resection ◽  
Benign Prostate Hyperplasia ◽  
Dynamic Mechanical Properties ◽  
Prostate Hyperplasia ◽  
Dynamic Mechanical ◽  
Benign Prostate

The objective is to establish the feasibility of using dynamic instrumented palpation, a novel technique of low-frequency mechanical testing, applied here to diagnose soft tissue condition. The technique is applied, in vitro, to samples of excised prostate gland affected by benign prostate hyperplasia and/or prostate cancer. Particular attention is paid to the relationship between the histological structure of the tissue and the dynamic mechanical properties in an attempt to separate patient-specific aspects from histopathological condition (i.e. prostate cancer or benign prostate hyperplasia). The technique is of clinical interest because it is potentially deployable in vivo. Prostate samples were obtained from a total of 36 patients who had undergone transurethral resection of the prostate to relieve prostatic obstruction and 4 patients who had undergone radical cystoprostatectomy for bladder cancer. Specimens (chips) recovered from transurethral resection of the prostate were of nominal size 5 mm × 8 mm and thicknesses between 2 and 4 mm, whereas those from the cystoprostatectomy were in the form of transverse slices of thickness approximately 6 mm. Specimens were mechanically tested by a controlled strain cyclic compression technique, and the resulting dynamic mechanical properties expressed as the amplitude ratio and phase difference between the cyclic stress and cyclic strain. After mechanical testing, the percentage areas of glandular and smooth muscle were measured at each probe point. Good contrast between the dynamic modulus of chips from benign prostate hyperplasia and prostate cancer patients was demonstrated, and absolute values similar to those published by other authors are reported. For the slices, modulus values were considerably higher than for chips, and good in-patient mechanical contrast was revealed for predominantly nodular and predominantly stromal areas. Extending this classification between patients required pattern recognition techniques. Overall, the study has demonstrated that dynamic mechanical properties can potentially be used for diagnosis of prostate condition using in vivo measurements.

Mechanism of Slow Crack Growth in Polyethylene: A Finite Element Approach

2015 ◽  
Author(s):  
Xiangpeng Luo ◽  
Jianfeng Shi ◽  
Jinyang Zheng
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Failure Time ◽  
Bulk Material ◽  
Slow Crack Growth ◽  
Damage Model ◽  
Constitutive Models ◽  
Fe Model ◽  
Notch Angle ◽  
Craze Zone

Slow crack growth (SCG) is a common failure mode in underground polyethylene (PE) piping which was designed for 50-year services. It had been revealed by experiments that the SCG process is caused by continuous propagation of the craze zone at the crack tip through the bulk material. However, the mechanism of SCG failure has not been understood clearly. The eXtended Finite Element Method (XFEM) is found to be an effective tool for locally non-smooth features (voids, cracks, etc.) in solid or fluid mechanics solutions. In this paper the time-dependent property of PE was considered, a viscoelastic constitutive model was used for the bulk material. To represent the material deterioration during SCG, a damage model was developed for the craze zone. Combined with the XFEM, the process of the Pennsylvania Notched Test (PENT), which had been widely applied for characterizing resistance of SCG for PE pipes or resins, was analyzed based on the proposed finite element (FE) model containing the two constitutive models. The numerical results were then compared with the experimental data in literatures. It showed that the failure time and final notch angle were in agreement with the experimental observations. Based on the verified FE model, strain distributions along the boundary of the crack were studied and the shortcomings of this model were discussed.

In-Vivo Mechanical Properties of Soft Tissue Covering Bony Prominences

1978 ◽  
Vol 100 (4) ◽  
pp. 194-201 ◽  
Author(s):  
J. C. Ziegert ◽  
J. L. Lewis
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Dynamic Loading ◽  
Static Loading ◽  
Mechanical Response ◽  
Bony Prominence ◽  
Soft Tissue Covering

In order to measure in-vivo bone accelerations, it is necessary to know the mechanical response of the soft tissue covering areas of bony prominence when a load is applied through a rigid contactor. Two methods are presented for determining this response in vivo. The first method is for quasi-static loading and the second method is for dynamic loading at approximately 2000 Hz. Results are presented for various subjects and contactor geometries.

Accuracy of Non-linear FE Modelling for Surgical Simulation: Study Using Soft Tissue Phantom

2010 ◽  
pp. 29-41 ◽  
Author(s):  
Jiajie Ma ◽  
Adam Wittek ◽  
Surya Singh ◽  
Grand Roman Joldes ◽  
Toshikatsu Washio ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Simulation Study ◽  
Surgical Simulation ◽  
Fe Modelling ◽  
Tissue Phantom ◽  
Non Linear
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