Effects of Hydrocortisone and β-Aminopropionitrile on Stress-Strain and Stress-Relaxation Behaviors, and Birefringent Retardation of Collagen Fibers in the Rat Incisor Periodontal Ligament

2002 ◽  
Vol 43 (4) ◽  
pp. 581-588 ◽  
Author(s):  
K. Komatsu ◽  
M. Kanazashi ◽  
T. Arai ◽  
M. Chiba
Keyword(s):  
Stress Relaxation ◽  
Periodontal Ligament ◽  
Collagen Fibers ◽  
Stress Strain ◽  
Rat Incisor

Effects of age on the stress–strain and stress–relaxation properties of the rat molar periodontal ligament

2004 ◽  
Vol 49 (10) ◽  
pp. 817-824 ◽  
Author(s):  
K. Komatsu ◽  
M. Kanazashi ◽  
A. Shimada ◽  
T. Shibata ◽  
A. Viidik ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Periodontal Ligament ◽  
Stress Strain ◽  
Relaxation Properties ◽  
Rat Molar

scholarly journals Mechanical Properties and Microstructural Collagen Alignment of the Ulnar Collateral Ligament During Dynamic Loading

2018 ◽  
Vol 47 (1) ◽  
pp. 151-157 ◽  
Author(s):  
Matthew V. Smith ◽  
Ryan M. Castile ◽  
Robert H. Brophy ◽  
Ashvin Dewan ◽  
David Bernholt ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Real Time ◽  
Strain Curve ◽  
Ulnar Collateral Ligament ◽  
Collagen Fibers ◽  
Stress Strain Curve ◽  
Collateral Ligament ◽  
Stress Strain ◽  
Collagen Organization ◽  
Collagen Alignment

Background: The ulnar collateral ligament (UCL) microstructural organization and collagen fiber realignment in response to load are unknown. Purpose/Hypothesis: The purpose was to describe the real-time microstructural collagen changes in the anterior bundle (AB) and posterior bundle (PB) of the UCL with tensile load. It was hypothesized that the UCL AB is stronger and stiffer with more highly aligned collagen during loading when compared with the UCL PB. Study Design: Descriptive laboratory study. Methods: The AB and PB from 34 fresh cadaveric specimens were longitudinally sectioned to allow uniform light passage for quantitative polarized light imaging. Specimens were secured to a tensile test machine and underwent cyclic preconditioning, a ramp-and-hold stress-relaxation test, and a quasi-static ramp to failure. A division-of-focal-plane polarization camera captured real-time pixelwise microstructural data of each sample during stress-relaxation and at the zero, transition, and linear points of the stress-strain curve. The SD of the angle of polarization determined the deviation of the average direction of collagen fibers in the tissue, while the average degree of linear polarization evaluated the strength of collagen alignment in those directions. Since the data were nonnormally distributed, the median ± interquartile range are presented. Results: The AB has larger elastic moduli than the PB ( P < .0001) in the toe region (median, 2.73 MPa [interquartile range, 1.1-5.6 MPa] vs 0.65 MPa [0.44-1.5 MPa]) and the linear region (13.77 MPa [4.8-40.7 MPa] vs 1.96 MPa [0.58-9.3 MPa]). The AB demonstrated larger stress values, stronger collagen alignment, and more uniform collagen organization during stress-relaxation. PB collagen fibers were more disorganized than the AB during the zero ( P = .046), transitional ( P = .011), and linear ( P = .007) regions of the stress-strain curve. Both UCL bundles exhibited very small changes in collagen alignment (SD of the angle of polarization) with load. Conclusion: The AB of the UCL is stiffer and stronger, with more strongly aligned and more uniformly oriented collagen fibers, than the PB. The small changes in collagen alignment indicate that the UCL response to load is due more to its static collagen organization than to dynamic changes in collagen alignment. Clinical Relevance: The UCL collagen organization may explain its susceptibility to injury with repetitive valgus loads.

scholarly journals Polarized light microscopic analyses of collagen fibers in the rat incisor periodontal ligament in relation to areas, regions, and ages

2002 ◽  
Vol 268 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Koichiro Komatsu ◽  
Lis Mosekilde ◽  
Andrus Viidik ◽  
Mototsugu Chiba
Keyword(s):  
Periodontal Ligament ◽  
Polarized Light ◽  
Collagen Fibers ◽  
Rat Incisor

scholarly journals Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

ACS Omega ◽  
2021 ◽  
Author(s):  
Takahiro Doi ◽  
Hideaki Takagi ◽  
Nobutaka Shimizu ◽  
Noriyuki Igarashi ◽  
Shinichi Sakurai
Keyword(s):  
Block Copolymers ◽  
Stress Relaxation ◽  
Stress Strain

scholarly journals A Simplified Method for Elastic-Plastic-Creep Structural Analysis

1985 ◽  
Vol 107 (1) ◽  
pp. 231-237 ◽  
Author(s):  
A. Kaufman
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Kinematic Hardening ◽  
Nonlinear Finite Element ◽  
Strain History ◽  
Stress Strain ◽  
Element Analysis ◽  
Inelastic Analysis ◽  
Simplified Method ◽  
Time Required

A simplified inelastic analysis computer program (ANSYMP) was developed for predicting the stress-strain history at the critical location of a thermomechanically cycled structure from an elastic solution. The program uses an iterative and incremental procedure to estimate the plastic strains from the material stress-strain properties and a plasticity hardening model. Creep effects can be calculated on the basis of stress relaxation at constant strain, creep at constant stress or a combination of stress relaxation and creep accumulation. The simplified method was exercised on a number of problems involving uniaxial and multiaxial loading, isothermal and nonisothermal conditions, dwell times at various points in the cycles, different materials, and kinematic hardening. Good agreement was found between these analytical results and nonlinear finite element solutions for these problems. The simplified analysis program used less than 1 percent of the CPU time required for a nonlinear finite element analysis.

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