Implant-abutment assemblies are usually subject to long-term cyclic loading. To evaluate the dynamic fatigue performance of implant-abutment assemblies with different tightening torque values, thirty implant-abutment assemblies (Zimmer Dental, Carlsbad, CA, USA) were randomly assigned to three tightening groups (24 Ncm; 30 Ncm; 36 Ncm), each consisted of 10 implants. Five specimens from each gr...

A new mixed-mode threshold stress intensity factor is developed using a critical plane-based multiaxial fatigue theory and the Kitagawa diagram. The proposed method is a nominal approach since the fatigue damage is evaluated using remote stresses acting on a cracked component rather than stresses near the crack tip. An equivalent stress intensity factor defined on the critical plane is proposed...

Fatigue or stress fractures are an important clinical problem in humans as well as racehorses. An important question in this context is, when a bone experiences fatigue damage during extreme use, how much is it weakened compared to its original state? Since there are very limited data on this question and stress fractures are common in racehorses, we sought to determine the effect of fatigue lo...

In polycrystalline metals, local deformation heterogeneities induced by the microstructure influence fatigue crack initiation and micro-crack propagation. The localization in plastic strains associated with heterogeneous deformation has been described as a necessary condition and a precursor for the nucleation of fatigue cracks. However, a clear and quantitative assessment of the correlation be...

The applicability of several fatigue damage models for polyether ether ketone (PEEK) under mean strain and variable amplitude multi-block loadings is evaluated. The models utilized in this study are assessed against experimental data for PEEK under various cyclic loading conditions, including (1) constant amplitude loading with non-zero mean strains, (2) two-block loading with zero and non-zero...

Introduction: Until the mechanics of anterior cruciate ligament (ACL) injuries and contributing factors are better elucidated, effective preventive strategies will continue to elude us. Current dogma is that ACL injury results from a single loading cycle, but recent evidence supports tissue fatigue as a possible failure mechanism [1]. In a cadaveric pivot landing model, ACL rupture was found to...

UNLABELLED Using a mechanical loading program to induce bone adaptation, we found that small (<2-fold) changes in the structural properties of the rat ulna increased its fatigue resistance >100-fold. This indicates that a moderate exercise program may be an effective preventative strategy for stress fractures. INTRODUCTION There are currently limited preventative strategies for stress fractur...

An in-vitro experiment was designed to investigate the mode of failure following shear fatigue loading of lumbar motion-segments. Human male lumbar motion-segments (age 32-42 years, n=6) were immersed in Ringer solution at 37°C and repeatedly loaded, using a modified materials testing machine. Fatigue loading consisted of a sinusoidal shear load from 0 N to 1,500 N (750 N±750 N) applied to the ...

In this paper, a Paris law-based model is presented whereby crack propagation occurs under cyclic loading in air (fatigue) and in an aggressive environment (corrosion-fatigue) for the case of corner cracks (with a wide range of aspect ratios in the matter of the initial cracks) in finite-thickness plates of 316L austenitic stainless steel subjected to tension, bending, or combined (tension + be...