scholarly journals Ratcheting response of biological tissues over asymmetric loading cycles

2021 ◽  
Author(s):  
Mahboubeh Sadat Hashemi
Keyword(s):  
Experimental Data ◽  
Strain Curve ◽  
Biological Tissues ◽  
Parametric Model ◽  
Stress Strain Curve ◽  
Stress Variation ◽  
Ratcheting Strain ◽  
Asymmetric Loading ◽  
Model Predictions ◽  
Failure Region

The purpose of this study is to examine the ratcheting phenomenon in a variety of biological tissues including the trabecular bone, meniscus, articular cartilage and skin, and propose a parametric model to predict the ratcheting strain of these tissues. Furthermore, utilizing experimental data, and the influence of different mechanical and biological parameters on the ratcheting strain are discussed. The dependency of ratcheting on frequency, stress rate, stress variation, physiological environment, and tissue sites is demonstrated. Besides, stiffness of the toe and linear regions in each cycle, and the modulus of the failure region of the stress-strain curve are computed. The energy dissipation in different cycles at two frequencies of 1 Hz and 10 Hz is discussed. A parametric model was employed to predict ratcheting behavior of the said biological tissues. The model predictions of the strain accumulation in tissues are found in agreement with the experimental data.

scholarly journals Ratcheting response of biological tissues over asymmetric loading cycles

2021 ◽  
Author(s):  
Mahboubeh Sadat Hashemi
Keyword(s):  
Experimental Data ◽  
Strain Curve ◽  
Biological Tissues ◽  
Parametric Model ◽  
Stress Strain Curve ◽  
Stress Variation ◽  
Ratcheting Strain ◽  
Asymmetric Loading ◽  
Model Predictions ◽  
Failure Region

The purpose of this study is to examine the ratcheting phenomenon in a variety of biological tissues including the trabecular bone, meniscus, articular cartilage and skin, and propose a parametric model to predict the ratcheting strain of these tissues. Furthermore, utilizing experimental data, and the influence of different mechanical and biological parameters on the ratcheting strain are discussed. The dependency of ratcheting on frequency, stress rate, stress variation, physiological environment, and tissue sites is demonstrated. Besides, stiffness of the toe and linear regions in each cycle, and the modulus of the failure region of the stress-strain curve are computed. The energy dissipation in different cycles at two frequencies of 1 Hz and 10 Hz is discussed. A parametric model was employed to predict ratcheting behavior of the said biological tissues. The model predictions of the strain accumulation in tissues are found in agreement with the experimental data.

scholarly journals Modelling of the behaviour of metal foams under shock compression

2018 ◽  
Vol 183 ◽  
pp. 01041
Author(s):  
Nicolas Jacques ◽  
Romain Barthélémy
Keyword(s):  
Experimental Data ◽  
Excellent Agreement ◽  
Strain Curve ◽  
Metal Foams ◽  
Cellular Materials ◽  
Theoretical Modelling ◽  
Stress Strain Curve ◽  
Open Cell ◽  
Proposed Model ◽  
Shock Response

A theoretical modelling is proposed to describe the shock response of foam materials. This model is based on micromechanical and energetic arguments, and takes into account the contribution of microscale inertia. Within this framework, an analytical expression of the Hugoniot stress-strain curve is proposed for elastic-plastic cellular materials. The predictions derived from the proposed model are in excellent agreement with experimental data for open-cell aluminium foams. The case of viscoplastic foams is also considered.

RESEARCH OF MAXILLARY IMPACTED CANINE IN ORTHODONTIC TREATMENT BASED ON NANOINDENTATION EXPERIMENTS

2017 ◽  
Vol 17 (07) ◽  
pp. 1740029
Author(s):  
BIN WU ◽  
YUNYUN ZHU ◽  
RUXIN LU ◽  
BIN YAN ◽  
YIPENG FU ◽  
...  
Keyword(s):  
Orthodontic Treatment ◽  
Strain Curve ◽  
Root Apex ◽  
Stress Strain Curve ◽  
Third Order ◽  
Stress Variation ◽  
The Third ◽  
Ogden Model ◽  
Impacted Canine ◽  
Good Agreement

This study selected the maxillary labial impacted canine as the research object to build the model of periodontal ligament (PDL) and simulate the process of orthodontic treatment. This paper obtained stress–strain curve by calculating and analyzing the data of nanoindentation experiments. The parameters were identified through curve fittings by ABAQUS. The fitting results show that the third-order Ogden model is in good agreement with the experimental data which demonstrate that the third-order Ogden model is able to reflect the material properties of the PDL. In this paper, orthodontic process of the maxillary labial impacted canine was simulated. The results show that inside and outside surfaces of PDL all have stress variation, the stress on the root apex and dental cervix of PDL is relatively large, the maximum appears at dental cervix and the minimum appears close to tooth impedance center.

Theories and Experiments on Tube Sinking through Conical Dies

1967 ◽  
Vol 182 (1) ◽  
pp. 19-32 ◽  
Author(s):  
G. G. Moore ◽  
J. F. Wallace
Keyword(s):  
Experimental Data ◽  
Velocity Field ◽  
Strain Hardening ◽  
Lower Bounds ◽  
Coulomb Friction ◽  
Strain Curve ◽  
Upper Bounds ◽  
Stress Strain Curve ◽  
Hardening Material ◽  
Field Techniques

Earlier theories of tube sinking through conical dies have been considered and the factors important in the calculation of stresses and strains have been determined. Using these theories drawing stresses have been calculated for a particular stress-strain curve by assuming an exponential strain hardening characteristic. These drawing stresses are essentially ‘lower bounds’ but comparative ‘upper bounds’ have been obtained using velocity field techniques; Coulomb friction has been included. Thickness strains for a smooth die and a non-strain hardening material have been computed. Experimental data has been obtained using conical dies under normal industrial conditions and comparisons made with theory. In addition, the problems encountered in the inlet and exit of the die are discussed. It is suggested that drawing stresses and thickness strains determined for conical dies can be applied to other die profiles when the die inlet semi-angle does not exceed 15°.

Constitutive Relation of Open-Celled Metal Foams Based on the Mesoscopic Behavior of Random Cells

2007 ◽  
Vol 340-341 ◽  
pp. 403-408 ◽  
Author(s):  
Ling Ling Hu ◽  
Xiao Qing Huang ◽  
Li Qun Tang
Keyword(s):  
Experimental Data ◽  
Mechanical Behavior ◽  
Constitutive Relation ◽  
Metal Foam ◽  
Strain Curve ◽  
Metal Foams ◽  
Stress Strain Curve ◽  
Yield Strain ◽  
Compression Process ◽  
Good Agreement

The constitutive relation for open-celled metal foams with random characteristics of cells was constructed based on the mechanical behavior and the distribution of the cells, which implied the effect of the mesoscopic characteristics of the cells on the macroscopic behavior of the foam. The constitutive relation was able to represent the whole three phases of the stress-strain curve of the open-celled metal foam with merely one expression. Besides, the explicit expressions for the foam’s yield strain and yield stress were supplied. Experimental data was employed to check the constitutive relation. It was found that the constitutive relation was able to represent accurately the whole compression process of the foams, and the calculated yield points had a good agreement with the experimental results.

scholarly journals Loading-Rate Dependency of Stress-Strain Curve for Rocks in the Post-Failure Region

2009 ◽  
Vol 125 (3) ◽  
pp. 98-105 ◽  
Author(s):  
Kimihiro HASHIBA ◽  
Ming LEI ◽  
Seisuke OKUBO ◽  
Katsunori FUKUI
Keyword(s):  
Loading Rate ◽  
Strain Curve ◽  
Rate Dependency ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Failure Region

Interrelation of Creep and Relaxation: A Modeling Approach for Ligaments

1999 ◽  
Vol 121 (6) ◽  
pp. 612-615 ◽  
Author(s):  
R. S. Lakes ◽  
R. Vanderby
Keyword(s):  
Experimental Data ◽  
Nonlinear Viscoelasticity ◽  
Strain Curve ◽  
Constitutive Law ◽  
Published Data ◽  
Superposition Model ◽  
Relaxation Data ◽  
Stress Strain Curve ◽  
Nonlinear Superposition ◽  
Single Integral

Experimental data (Thornton et al., 1997) show that relaxation proceeds more rapidly (a greater slope on a log-log scale) than creep in ligament, a fact not explained by linear viscoelasticity. An interrelation between creep and relaxation is therefore developed for ligaments based on a single-integral nonlinear superposition model. This interrelation differs from the convolution relation obtained by Laplace transforms for linear materials. We demonstrate via continuum concepts of nonlinear viscoelasticity that such a difference in rate between creep and relaxation phenomenologically occurs when the nonlinearity is of a strain-stiffening type, i.e., the stress-strain curve is concave up as observed in ligament. We also show that it is inconsistent to assume a Fung-type constitutive law (Fung, 1972) for both creep and relaxation. Using the published data of Thornton et al. (1997), the nonlinear interrelation developed herein predicts creep behavior from relaxation data well (R ≥ 0.998). Although data are limited and the causal mechanisms associated with viscoelastic tissue behavior are complex, continuum concepts demonstrated here appear capable of interrelating creep and relaxation with fidelity.

A modified version of MATLAB application window for predicting the weld bead profile and stress–strain plot of AA5052 CMT weldment using ER4043

SIMULATION ◽  
2021 ◽  
pp. 003754972110315
Author(s):  
B Girinath ◽  
N Siva Shanmugam
Keyword(s):  
Strain Curve ◽  
Weld Bead ◽  
Welding Parameters ◽  
Bead Geometry ◽  
Hybrid Technique ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Weld Bead Geometry ◽  
Inference System ◽  
Engineering Stress

The present study deals with the extended version of our previous research work. In this article, for predicting the entire weld bead geometry and engineering stress–strain curve of the cold metal transfer (CMT) weldment, a MATLAB based application window (second version) is developed with certain modifications. In the first version, for predicting the entire weld bead geometry, apart from weld bead characteristics, x and y coordinates (24 from each) of the extracted points are considered. Finally, in the first version, 53 output values (five for weld bead characteristics and 48 for x and y coordinates) are predicted using both multiple regression analysis (MRA) and adaptive neuro fuzzy inference system (ANFIS) technique to get an idea related to the complete weld bead geometry without performing the actual welding process. The obtained weld bead shapes using both the techniques are compared with the experimentally obtained bead shapes. Based on the results obtained from the first version and the knowledge acquired from literature, the complete shape of weld bead obtained using ANFIS is in good agreement with the experimentally obtained weld bead shape. This motivated us to adopt a hybrid technique known as ANFIS (combined artificial neural network and fuzzy features) alone in this paper for predicting the weld bead shape and engineering stress–strain curve of the welded joint. In the present study, an attempt is made to evaluate the accuracy of the prediction when the number of trials is reduced to half and increasing the number of data points from the macrograph to twice. Complete weld bead geometry and the engineering stress–strain curves were predicted against the input welding parameters (welding current and welding speed), fed by the user in the MATLAB application window. Finally, the entire weld bead geometries were predicted by both the first and the second version are compared and validated with the experimentally obtained weld bead shapes. The similar procedure was followed for predicting the engineering stress–strain curve to compare with experimental outcomes.

scholarly journals Experimental Study on Biaxial Dynamic Compressive Properties of ECC

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1257
Author(s):  
Shuling Gao ◽  
Guanhua Hu
Keyword(s):  
Strain Rate ◽  
Lateral Pressure ◽  
Deformation Modulus ◽  
Strain Curve ◽  
Peak Stress ◽  
Pressure Level ◽  
Strain Rates ◽  
Peak Strain ◽  
Stress Strain Curve ◽  
Toughness Index

An improved hydraulic servo structure testing machine has been used to conduct biaxial dynamic compression tests on eight types of engineered cementitious composites (ECC) with lateral pressure levels of 0, 0.125, 0.25, 0.5, 0.7, 0.8, 0.9, 1.0 (the ratio of the compressive strength applied laterally to the static compressive strength of the specimen), and three strain rates of 10−4, 10−3 and 10−2 s−1. The failure mode, peak stress, peak strain, deformation modulus, stress-strain curve, and compressive toughness index of ECC under biaxial dynamic compressive stress state are obtained. The test results show that the lateral pressure affects the direction of ECC cracking, while the strain rate has little effect on the failure morphology of ECC. The growth of lateral pressure level and strain rate upgrades the limit failure strength and peak strain of ECC, and the small improvement is achieved in elastic modulus. A two-stage ECC biaxial failure strength standard was established, and the influence of the lateral pressure level and peak strain was quantitatively evaluated through the fitting curve of the peak stress, peak strain, and deformation modulus of ECC under various strain rates and lateral pressure levels. ECC’s compressive stress-strain curve can be divided into four stages, and a normalized biaxial dynamic ECC constitutive relationship is established. The toughness index of ECC can be increased with the increase of lateral pressure level, while the increase of strain rate can reduce the toughness index of ECC. Under the effect of biaxial dynamic load, the ultimate strength of ECC is increased higher than that of plain concrete.

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