During fatigue tests of cortical bone specimens, at the unload portion of the cycle (zero stress) non-zero strains occur and progressively accumulate as the test progresses. This non-zero strain is hypothesised to be mostly, if not entirely, describable as creep. This work examines the rate of accumulation of this strain and quantifies its stress dependency. A published relationship determined from creep tests of cortical bone (Journal of Biomechanics 21 (1988) 623) is combined with knowledge of the stress history during fatigue testing to derive an expression for the amount of creep strain in fatigue tests. Fatigue tests on 31 bone samples from four individuals showed strong correlations between creep strain rate and both stress and "normalised stress" (sigma/E) during tensile fatigue testing (0-T). Combined results were good (r(2)=0.78) and differences between the various individuals, in particular, vanished when effects were examined against normalised stress values. Constants of the regression showed equivalence to constants derived in creep tests. The universality of the results, with respect to four different individuals of both sexes, shows great promise for use in computational models of fatigue in bone structures.
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http://dx.doi.org/10.1016/s0021-9290(03)00063-0 | DOI Listing |
Sci Rep
December 2024
School of Civil Engineering and Architecture, Guizhou Minzu University, Guiyang, 550025, China.
Phosphogypsum is the main industrial solid waste from wet process phosphoric acid production, which has significant potential for environmental sustainability and engineering applications when modified. In order to explore the mechanical properties of modified phosphogypsum (MG) in different loading environments, uniaxial compression tests were conducted at four loading rates: 0.03, 0.
View Article and Find Full Text PDFGels
November 2024
School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.
This study presents the development of thiol-maleimide/thiol-thiol double self-crosslinking hyaluronic acid-based (HA) hydrogels for use as dermal fillers. Hyaluronic acid with varying degrees of maleimide substitution (10%, 20%, and 30%) was synthesized and characterized, and HA hydrogels were fabricated using two molecular weights of four-arm polyethylene glycol (PEG10K/20K)-thiol as crosslinkers. The six resulting HA hydrogels demonstrated solid-like behavior with distinct physical and rheological properties.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
College of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
The study of dredged fill in Guangdong (GD), China, is of great significance for reclamation projects. Currently, there are relatively few studies on dredged fill in Guangdong, and there are many differences in the engineering characteristics of dredged fill foundations formed through land reclamation and natural foundations. In order to have a more comprehensive understanding of the physico-mechanical properties of blowing fill in the coastal area of GD and to understand the effect of its long-term creep row on the long-term settlement and deformation of buildings, the material properties, microstructure, elemental composition, triaxial shear properties, and triaxial creep properties of dredged fill in Guangdong were studied and analyzed through indoor geotechnical tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), and conventional triaxial shear tests and triaxial creep tests.
View Article and Find Full Text PDFJ Clin Exp Dent
November 2024
Ph.D. Postdoc. Titular Professor. Biomedical Stomatology Research Group, School of Dentistry. Universidad de Antioquia U de A, Medellín Colombia.
Background: Previous studies have identified the effects of light curing techniques on both shrinkage strain and contraction stress buildup in composite restorations. Finite Element Analysis (FEA) has several advantages over other experimental methods for evaluating the mechanical properties of direct dental resins. The objective of this systematic review is to assess the impact of light curing protocols on the shrinkage behaviors and other mechanical properties of direct restorative composites utilizing FEA.
View Article and Find Full Text PDFPLoS One
December 2024
Sinosteel Maanshan General Institute of Mining Research CO.,Ltd., Maanshan, China.
Hard structural planes mainly exist in rock slopes and their creep characteristics largely determine slope stability. Traditional models have some shortcomings in describing the creep characteristics of hard structural planes, such as poor adaptability and unclear physical meaning of parameters. In order to overcome these shortcomings, based on the creep failure mechanism of hard structural planes, an element combination model is adopted in the study.
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