Basic Biomechanics for Craniofacial Surgeons: The Responses of Alloplastic Materials and Living Tissues to Mechanical Forces

FACE ◽  
2021 ◽  
pp. 273250162110602
Author(s):  
Jack C. Yu ◽  
Steven R. Buchman ◽  
Arun K. Gosain ◽  
Robert J. Havlik ◽  
Tien-Hsiang Wang ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Soft Tissues ◽  
Environmental Changes ◽  
Young's Modulus ◽  
Time Dependent ◽  
External Fixators ◽  
Craniofacial Skeleton ◽  
Stress Strain ◽  
Viscoelastic Composite ◽  
Alloplastic Materials

Many terms such as twist, compress, bend, and stretch, describe how materials behave when subjected to mechanical stresses. Subjective adjectives to describe the property of materials such as hard or brittle are imprecise and impedes proper understanding of important principles needed in planning and performing surgical treatments. The viability of tissue and time dependent variables effect healing and compound the issue. Some parameters are time dependent (strain rate), while others are nearly independent of time (Young’s modulus). The craniofacial skeleton and enveloping soft tissues are viscoelastic composite materials which undergo time-dependent changes upon loading. The ability to remodel and respond to environmental changes makes them “smart,” reenforcing where needed and removing where not required based on a set of predetermined upper and lower thresholds. This mini review has 7 sections on engineering principles that underpin craniofacial surgery: (1) The general concept of mechanics: load, force, stress, strain, compression, tension, shear, stress-strain curves and values derived from them such as Young’s modulus, fatigue damage, and load- shearing. (2) Material properties of bone and suture and structural engineering of the craniofacial skeleton in normal and pathological conditions. (3) Fixation using wires, screws, and plates: anatomy and function of screws and plates, locking plates, lag screws, internal and external fixators. (4) Biomechanics of distraction osteogenesis and the effects of radiation. (5) Finite element analysis and other computational biomechanical tools. (6) Virtual surgical planning, cutting guides, and intra-operative navigation. (7) Tissue engineering: design goals, criteria, and constraints. An appreciation and understanding of these biomechanical principles will help craniofacial surgeons to facilitate intrinsic optimization and better treat complex morphological problems, helping one achieve the most favorable and durable results. The biological responses to mechanical stress are extremely important as well, but due to space constraints, they will be the subject of a separate dedicated review.

scholarly journals Developing a Quantifying Device for Soft Tissue Material Prop-Erties around Lumbar Spines

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee
Keyword(s):  
Lumbar Spine ◽  
Soft Tissue ◽  
Young’S Modulus ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress And Strain ◽  
Commercial Device ◽  
Tissue Material

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

Numerical Modeling of Macroscopic Behavior of Particulate Composite with Crosslinked Polymer Matrix

2011 ◽  
Vol 465 ◽  
pp. 129-132
Author(s):  
Luboš Náhlík ◽  
Bohuslav Máša ◽  
Pavel Hutař
Keyword(s):  
Young’S Modulus ◽  
Polymer Matrix ◽  
Young's Modulus ◽  
Numerical Models ◽  
Strain Curve ◽  
Particulate Composite ◽  
Material Behavior ◽  
Particulate Composites ◽  
Stress Strain ◽  
Crosslinked Polymer

Particulate composites with crosslinked polymer matrix and solid fillers are one of important classes of materials such as construction materials, high-performance engineering materials, sealants, protective organic coatings, dental materials, or solid explosives. The main focus of a present paper is an estimation of the macroscopic Young’s modulus and stress-strain behavior of a particulate composite with polymer matrix. The particulate composite with a crosslinked polymer matrix in a rubbery state filled by an alumina-based mineral filler is investigated by means of the finite element method. A hyperelastic material behavior of the matrix was modeled by the Mooney-Rivlin material model. Numerical models on the base of unit cell were developed. The numerical results obtained were compared with experimental stress-strain curve and value of initial Young’s modulus. The paper can contribute to a better understanding of the behavior and failure of particulate composites with a crosslinked polymer matrix.

scholarly journals Quantifying the Contribution of Crystallographic Texture and Grain Morphology on the Elastic and Plastic Anisotropy of bcc Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1252 ◽  
Author(s):  
Martin Diehl ◽  
Jörn Niehuesbernd ◽  
Enrico Bruder
Keyword(s):  
Young’S Modulus ◽  
Crystallographic Texture ◽  
Young's Modulus ◽  
Hsla Steel ◽  
Geometric Mean ◽  
Plastic Anisotropy ◽  
Grain Morphology ◽  
Strain Partitioning ◽  
Stress Strain ◽  
Full Field

The influence of grain shape and crystallographic orientation on the global and local elastic and plastic behaviour of strongly textured materials is investigated with the help of full-field simulations based on texture data from electron backscatter diffraction (EBSD) measurements. To this end, eight different microstructures are generated from experimental data of a high-strength low-alloy (HSLA) steel processed by linear flow splitting. It is shown that the most significant factor on the global elastic stress–strain response (i.e., Young’s modulus) is the crystallographic texture. Therefore, simple texture-based models and an analytic expression based on the geometric mean to determine the orientation dependent Young’s modulus are able to give accurate predictions. In contrast, with regards to the plastic anisotropy (i.e., yield stress), simple analytic approaches based on the calculation of the Taylor factor, yield different results than full-field microstructure simulations. Moreover, in the case of full-field models, the selected microstructure representation influences the outcome of the simulations. In addition, the full-field simulations, allow to investigate the micro-mechanical fields, which are not readily available from the analytic expressions. As the stress–strain partitioning visible from these fields is the underlying reason for the observed macroscopic behaviour, studying them makes it possible to evaluate the microstructure representations with respect to their capabilities of reproducing experimental results.

Uniaxial Mechanical Properties of Sandstone under Cyclic of Drying and Wetting

2011 ◽  
Vol 243-249 ◽  
pp. 2310-2313 ◽  
Author(s):  
Hua Yan Yao ◽  
Zhen Hua Zhang ◽  
Zhao Hui Zhu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Test Results ◽  
Stress Strain ◽  
Deformation And Failure ◽  
Deformation Behaviors ◽  
Uniaxial Strength

Water is an important factor that influences the mechanical properties of rock. Uniaxial compressive experiments have been carried out on sandstone under different cyclic times of drying and wetting. The corresponding complete stress-strain curves are obtained, and characteristics of deformation and failure are analyzed. Test results show that when sandstone samples are submitted to cyclic of drying and wetting, the uniaxial strength and Young's modulus of sandstone obviously decrease. Then, the improved Duncan constitutive model is developed, which can do better in describing sample’s deformation behaviors subject to different cyclic times of drying and wetting. Introduction

Reconstructing Young’s Modulus Distributions within Soft Tissues From Freehand Elastograms

2006 ◽  
pp. 469-476 ◽  
Author(s):  
M. M. Doyley ◽  
J. C. Bamber ◽  
P. M. Meaney ◽  
F. G. Fuechsel ◽  
N. L. Bush ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Soft Tissues ◽  
Young's Modulus

scholarly journals Loading-Rate Dependency of Young’s Modulus for Class I and Class II Rocks

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hailong Zhang ◽  
Seisuke Okubo ◽  
Cancan Chen ◽  
Yang Tang ◽  
Jiang Xu
Keyword(s):  
Young’S Modulus ◽  
Loading Rate ◽  
Young's Modulus ◽  
Underlying Mechanism ◽  
Time Dependent ◽  
Rate Dependency ◽  
Underground Structures ◽  
Dependent Behavior ◽  
Rate Of Increase ◽  
Variable Compliance

Understanding the time-dependent behavior of rocks is important for ensuring the long-term stability of underground structures. Aspects of such a time-dependent behavior include the loading-rate dependency of Young’s modulus, strength, creep, and relaxation. In particular, the loading-rate dependency of Young’s modulus of rocks has not been fully clarified. In this study, four different types of rocks were tested, and the results were used to analyze the loading-rate dependency of Young’s modulus and explain the underlying mechanism. For all four rocks, Young’s modulus increased linearly with a tenfold increase in the loading rate. The rocks showed the same loading-rate dependency of Young’s modulus. A variable-compliance constitutive equation was proposed for the loading-rate dependency of Young’s modulus, and the calculated results agreed well with measured values. Irrecoverable and recoverable strains were separated by loading-unloading-reloading tests at preset stress levels. The constitutive equations showed that the rate of increase in Young’s modulus increased with the irrecoverable strain and decreased with increasing stress. The increase in the irrecoverable strain was delayed at high loading rates, which was concluded to be the main reason for the increase in Young’s modulus with an increasing loading rate.

Softness Measurement Technics of Human Skin by Indentation Devices Imitating Palpation

2013 ◽  
Author(s):  
Atsushi Sakuma
Keyword(s):  
Young’S Modulus ◽  
Human Skin ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Finite Thickness ◽  
The Body ◽  
Ultraviolet Rays ◽  
Spherical Indentation ◽  
Measurement Technology ◽  
Human Face

The characteristics of human skin are easily changed by the states of the body because it is very sensitive to environmental transformation. And the development of the condition measurement technology of human skin is very important for improvement in QOL because it reflects body condition. Then, various devices for the condition measurement of human skin had been developed but there was no technique which can evaluate the skin by objective parameter easily. In this paper, spherical indentation testing is studied to evaluate the dimension and rigidity of thin soft-tissues like human skin. Here, the Hertz contact theory is functionally expanded to evaluate indentations for the thin tissues. In the expansions, the technique used for evaluating the thickness of finite specimens is first explained by analyzing the experimental results of indentations. Then, the Young’s modulus of the tissue with finite thickness is theoretically derived by defining an equivalent indentation strain for the analysis of the indentation process. The expansions are examined to evaluate its reliability by applying them to measure Young’s modulus of some thin materials. Furthermore, this technology is applied to the elasticity investigation of the human skin. Especially, the measurement results of elasticity characteristics of the skin of human face are shown as the first report. The influences of sex and ultraviolet rays and so on are discussed to reveal the mechanics of human skin in this report. Moreover, it is discussed about the validity of the device which measures the elasticity of the skin of human face.

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