scholarly journals Accumulation of collagen molecular unfolding is the mechanism of cyclic fatigue damage and failure in collagenous tissues

2020 ◽  
Vol 6 (35) ◽  
pp. eaba2795 ◽  
Author(s):  
Jared L. Zitnay ◽  
Gang Seob Jung ◽  
Allen H. Lin ◽  
Zhao Qin ◽  
Yang Li ◽  
...  
Keyword(s):  
Cyclic Strain ◽  
Fatigue Loading ◽  
Mechanistic Explanation ◽  
Damage Mechanism ◽  
Cyclic Fatigue ◽  
Overuse Injuries ◽  
Time To Failure ◽  
Damage And Failure ◽  
Rate Dependent ◽  
Collagenous Tissues

Overuse injuries to dense collagenous tissues are common, but their etiology is poorly understood. The predominant hypothesis that micro-damage accumulation exceeds the rate of biological repair is missing a mechanistic explanation. Here, we used collagen hybridizing peptides to measure collagen molecular damage during tendon cyclic fatigue loading and computational simulations to identify potential explanations for our findings. Our results revealed that triple-helical collagen denaturation accumulates with increasing cycles of fatigue loading, and damage is correlated with creep strain independent of the cyclic strain rate. Finite-element simulations demonstrated that biphasic fluid flow is a possible fascicle-level mechanism to explain the rate dependence of the number of cycles and time to failure. Molecular dynamics simulations demonstrated that triple-helical unfolding is rate dependent, revealing rate-dependent mechanisms at multiple length scales in the tissue. The accumulation of collagen molecular denaturation during cyclic loading provides a long-sought “micro-damage” mechanism for the development of overuse injuries.

scholarly journals Effect of synchronous irrigation on cyclic fatigue of nickel-titanium instrument in the dynamic and static models

2021 ◽  
Vol 19 ◽  
pp. 228080002098740
Author(s):  
Haiyun Liu ◽  
Yanfeng Li ◽  
Guangquan Chai ◽  
Yuan Lv ◽  
Changjian Li ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Flow Rate ◽  
Dynamic Control ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Control Group ◽  
Time To Failure ◽  
Dynamic Tests ◽  
Significant Difference ◽  
Experimental Group

Objective: To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument. Methods: A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups ( N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups ( N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed. Results: According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups. Conclusion: Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

New anterior controllable antedisplacement and fusion surgery for cervical ossification of the posterior longitudinal ligament: a biomechanical study

2022 ◽  
pp. 1-9
Keyword(s):  
Fatigue Loading ◽  
Axial Rotation ◽  
Posterior Longitudinal Ligament ◽  
Cyclic Fatigue ◽  
Biomechanical Study ◽  
Biomechanical Stability ◽  
Loading Test ◽  
Crossover Effect ◽  
Flexion Extension

OBJECTIVE The traditional anterior approach for multilevel severe cervical ossification of the posterior longitudinal ligament (OPLL) is demanding and risky. Recently, a novel surgical procedure—anterior controllable antedisplacement and fusion (ACAF)—was introduced by the authors to deal with these problems and achieve better clinical outcomes. However, to the authors’ knowledge, the immediate and long-term biomechanical stability obtained after this procedure has never been evaluated. Therefore, the authors compared the postoperative biomechanical stability of ACAF with those of more traditional approaches: anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). METHODS To determine and assess pre- and postsurgical range of motion (ROM) (2 Nm torque) in flexion-extension, lateral bending, and axial rotation in the cervical spine, the authors collected cervical areas (C1–T1) from 18 cadaveric spines. The cyclic fatigue loading test was set up with a 3-Nm cycled load (2 Hz, 3000 cycles). All samples used in this study were randomly divided into three groups according to surgical procedures: ACDF, ACAF, and ACCF. The spines were tested under the following conditions: 1) intact state flexibility test; 2) postoperative model (ACDF, ACAF, ACCF) flexibility test; 3) cyclic loading (n = 3000); and 4) fatigue model flexibility test. RESULTS After operations were performed on the cadaveric spines, the segmental and total postoperative ROM values in all directions showed significant reductions for all groups. Then, the ROMs tended to increase during the fatigue test. No significant crossover effect was detected between evaluation time and operation method. Therefore, segmental and total ROM change trends were parallel among the three groups. However, the postoperative and fatigue ROMs in the ACCF group tended to be larger in all directions. No significant differences between these ROMs were detected in the ACDF and ACAF groups. CONCLUSIONS This in vitro biomechanical study demonstrated that the biomechanical stability levels for ACAF and ACDF were similar and were both significantly greater than that of ACCF. The clinical superiority of ACAF combined with our current results showed that this procedure is likely to be an acceptable alternative method for multilevel cervical OPLL treatment.

Wire Fatigue Models for Power Electronic Modules

2003 ◽  
Author(s):  
Karumbu Nathan Meyyappan ◽  
Peter Hansen ◽  
Patrick McCluskey
Keyword(s):  
Prediction Model ◽  
Life Prediction ◽  
Damage Model ◽  
Cyclic Strain ◽  
Temperature Cycling ◽  
Transformation Model ◽  
Time To Failure ◽  
Flexural Failure ◽  
The Wire ◽  
Life Prediction Model

This paper presents two, semi-analytical, physics-of-failure based life prediction model formulations for flexural failure of wires ultrasonically wedge bonded to pads at different heights. The life prediction model consists of a load transformation model and a damage model. The load transformation model determines the cyclic strain is created by a change in wire curvature at the heel of the wire resulting from expansion of the wire and displacement of the frame. The damage model calculates the life based on the strain cycle magnitude and the elastic-plastic fatigue response of the wire. The first formulation provides quick calculation of the time to failure for a wire of known geometry. The second formulation optimizes the wire geometry for maximum time to failure. These model formulations support virtual qualification of power modules where wire flexural fatigue is a dominant failure mechanism. The model has been validated using temperature cycling test results.

Computational simulation of the relaxation of local stresses due to foreign object damage under cyclic loading

2010 ◽  
Vol 224 (2) ◽  
pp. 41-50 ◽  
Author(s):  
T Davis ◽  
J Ding ◽  
W Sun ◽  
S B Leen
Keyword(s):  
Stress Relaxation ◽  
Kinematic Hardening ◽  
Computational Simulation ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Foreign Object ◽  
Stress Concentrations ◽  
Foreign Object Damage ◽  
Stress Ratios ◽  
The Impact

In this study, the phenomenon of residual stress relaxation from foreign object damage (FOD) is numerically simulated using a hybrid explicit—implicit finite-element method. The effects of cycle fatigue loadings on stress relaxation were studied. FOD is first simulated by firing a 3mm cube impacting onto a plate made of titanium alloy Ti-6Al-4V at 200m/s. The FOD impact produces two distinct stress concentrations: one is compressive directly beneath the impact site; the other is tensile around the outer edge of the impact. The plate was then assumed to be subjected to a cyclic fatigue loading. The stress relaxation was investigated under a range of stress ratios and maximum applied stresses. Two different material models were considered for the simulations, namely an elastic—perfectly plastic model and a non-linear kinematic hardening model.

Fatigue Evaluation in Ceramic Materials by Acoustic Emission

1993 ◽  
Author(s):  
Osama M. Jadaan ◽  
K. C. Liu ◽  
H. Pih
Keyword(s):  
Acoustic Emission ◽  
Count Rate ◽  
Fatigue Loading ◽  
Ceramic Materials ◽  
Cyclic Fatigue ◽  
Fracture Site ◽  
Progressive Damage ◽  
Catastrophic Failure ◽  
Final Fracture ◽  
Fatigue Evaluation

Abstract Progressive damage due to tension-tension cyclic fatigue loading for three distinct ceramic materials was evaluated using the acoustic emission (AE) technique. The objective of this study was to determine the capabilities of the AE method to detect the imminence of failure and to locate potential fracture sites. Results indicated that the AE technique was capable of predicting failure by showing an increase in energy/count rate prior to failure. Although potential fracture sites can be identified, exact location of the final fracture site can be known only when catastrophic failure takes place.

Fatigue–oxidation–creep damage model under axial-torsional thermo-mechanical loading

2019 ◽  
Vol 29 (5) ◽  
pp. 810-830 ◽  
Author(s):  
Dao-Hang Li ◽  
De-Guang Shang ◽  
Jin Cui ◽  
Luo-Jin Li ◽  
Ling-Wan Wang ◽  
...  
Keyword(s):  
Damage Model ◽  
Creep Damage ◽  
Fatigue Loading ◽  
Damage Mechanism ◽  
Critical Crack ◽  
Critical Crack Length ◽  
Mechanical Fatigue ◽  
Proposed Model ◽  
Oxidation Damage ◽  
Creep Damage Model

A fatigue–oxidation–creep damage model that can take into account the effect of multiaxial cyclic feature on the damage mechanism is proposed under axial-torsional thermo-mechanical fatigue loading. In the proposed model, the effects of non-proportional additional hardening on fatigue, oxidation, and creep damages are considered, and the variation of oxidation damage under different high temperature loading conditions is also described. Moreover, the intergranular creep damage needs to be equivalent to the transgranular damage before accumulating with the fatigue and oxidation damages. The fatigue, oxidation, and creep damages can be expressed as the fractions of fatigue life, critical crack length, and creep rupture time, respectively, which allows the linear accumulation of different types of damages on the basis of life fraction rule. In addition, the proposed model is validated by various fatigue experimental results, including uniaxial thermo-mechanical fatigue, axial-torsional thermo-mechanical fatigue, and isothermal axial-torsional fatigue under proportional and non-proportional loadings. The results showed that the errors are within a factor of 2.

Three-Dimensional Finite Element Prediction of Machining-Induced Stresses

Manufacturing ◽  
2003 ◽  
Author(s):  
T. D. Marusich ◽  
S. Usui ◽  
R. J. McDaniel
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Metal Cutting ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Fem Model ◽  
Machined Parts ◽  
Three Dimensional Finite Element

Controlling residual stress in machined workpiece surfaces is necessary in situations where service requirements subject structural members to cyclic fatigue loading. It is desirable to have a predictive capability when attempting to optimize machined parts for cost while taking into account residual stress considerations. One such method of machining modeling is application of the finite element method (FEM). A three-dimensional FEM model is presented which includes fully adaptive unstructured mesh generation, tight thermo-mechanically coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, momentum effects at high speeds and constitutive models appropriate for high strain rate, finite deformation analyses. The FEM model is applied to nose turning operations with stationary tools. To substantiate the efficacy of numerical and constitutive formulations used, metal cutting tests are performed, residual stress profiles collected, and validation comparison is made.

Sign in / Sign up

Export Citation Format

Share Document