in this paper, a new analytical method is proposed to study the effect of crack and axial load on vibration behavior and stability of the cracked columns. using the local flexibility model, the crack has been simulated by a torsional spring with connecting two segments of column in crack location. by solving governing eigenvalue equation, the effect of crack parameters and axial load on the nat...

the present study utilizes an analytical method to formulate the three lowest modal frequencies of axially-loaded notched beam through both crack location and load level in a specific format that can be used in existing frequency-based crack-identification methods. the proposed formula provides a basis to shift into two states, one with axial loading and the other without any loading whatsoever...

in this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. the oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. the present work focuses on the interactions of the pre-existing micro-cracks, which can grow and propagate within a rock-like specimen. the ...

The gradual discovery of functional domains in native enamel matrix proteins has enabled the design of smart bioinspired peptides for tooth enamel mimetics and repair. In this study, we expanded upon the concept of biomineralization to design smaller amelogenin-inspired peptides with conserved functional domains for clinical translation. The synthetic peptides displayed a characteristic nanostr...

Erosion is one of serious oral health problems among Japanese children. Some dentists argue that brushing just after food/drink intake induces enamel abrasion. Objectives of this study were to evaluate amount of calcium elution from bovine enamel due to single and short immersion into carbonated soft drink, to calculate depth of the eroded lesion, and to determine when to brush teeth after carb...

OBJECTIVE This in situ/ex vivo study investigated the effect of CO2 laser irradiation and acidulated phosphate fluoride gel (APF) application, separately and in combination, on enamel resistance to erosion. MATERIAL AND METHODS During 2 experimental 5-day crossover phases, 8 volunteers wore intraoral appliances containing bovine enamel blocks which were submitted to four groups: 1st phase - c...

Unlike other mineralized tissues, mature dental enamel is primarily (> 95% by weight) composed of apatitic crystals and has a unique hierarchical structure. Due to its high mineral content and organized structure, enamel has exceptional functional properties and is the hardest substance in the human body. Enamel formation (amelogenesis) is the result of highly orchestrated extracellular process...

This paper proposes a reliable and cost-effective two-phase methodology to predict crack propagation life in generic two-dimensional (2D) structural components. First, the usually curved fatigue crack path and its stress-intensity factors are calculated at small crack increments in a specialized finite-element software, using automatic remeshing algorithms, special crack tip elements and approp...

The aim of this in vitro study was to to evaluate the impact of finishing procedures on the enamel adjacent to composite restorations and to assess if the resistance of the enamel-resin junction to leakage is affected by the use of these instruments. The surfaces of enamel at the joint with composite were observed by scanning electron microscopy, then the microleakages at the enamel margin was ...

Image processing technologies are proposed to quantify crack patterns. On the basis of the technologies, a software “Crack Image Analysis System” (CIAS) has been developed. An image of soil crack network is used as an example to illustrate the image processing technologies and the operations of the CIAS. The quantification of the crack image involves the following three steps: image segmentatio...