scholarly journals Statistical Modelling of the Fatigue Bending Strength of Norway Spruce Wood

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 536
Author(s):  
Jernej Klemenc ◽  
Gorazd Fajdiga
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
Bending Strength ◽  
Mass Density ◽  
Statistical Modelling ◽  
Fatigue Properties ◽  
Novel Approach ◽  
Inverse Power Law ◽  
The Common ◽  
Constant Shape

When wood is used as a structural material, the fact that it is a highly inhomogeneous material, which significantly affects its static and fatigue properties, presents a major challenge to engineers. In this paper, a novel approach to modelling the fatigue-life properties of wood is presented. In the model, the common inverse-power-law relationship between the structural amplitude loads and the corresponding number of load cycles to failure is augmented with the influence of the wood’s mass density, the loading direction and the processing lot. The model is based on the two-parametric conditional Weibull’s probability density function with a constant shape parameter and a scale parameter that is a function of the previously mentioned parameters. The proposed approach was validated using the example of experimental static and fatigue-strength data from spruce beams. It turned out that the newly presented model is capable of adequately replicating the spruce’s S-N curves with a scatter, despite the relatively scarce amount of experimental data, which came from different production lots that were loaded in different directions and had a significant variation in density. Based on the experimental data, the statistical model predicts that the lower density wood has better fatigue strength.

Fatigue Bending Strength of Jones Fracture Specific Screw Fixation

2017 ◽  
Vol 39 (4) ◽  
pp. 493-499 ◽  
Author(s):  
James Jastifer ◽  
Kirk A. McCullough
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Fatigue Testing ◽  
Screw Fixation ◽  
Optimal Choice ◽  
Fatigue Properties ◽  
Strength Data ◽  
Screw Design ◽  
Jones Fracture ◽  
Significant Difference

Background: Intramedullary screw fixation is a common method of treating proximal metadiaphyseal fifth metatarsal (ie, Jones) fractures. Fatigue failure is a complication of this fixation. There are many screw designs available, including Jones fracture specific fixation, but the optimal choice of screw design is unknown. The purpose of this study was to compare the fatigue strength of Jones fracture specific screw designs as well as other commonly used screw designs. Our hypothesis was that there would be no difference in fatigue strength for Jones fracture specific screw designs at similar screw diameters. Methods: A study was performed to determine the fatigue bending strength of 5 different screw designs including Jones fracture specific screw designs at 3 different screw diameters. Six screws of each size and design underwent cyclic fatigue testing, and a median fatigue limit (MFL) was determined for each screw design and size. Results: The Stryker Asnis JFX solid 4.0-mm, 5.0-mm, and 6.0-mm screws had a higher MFL than all other screws with similar diameter tested (all P < .0001). Both Jones fracture specific screw designs (Stryker Asnis JFX solid screws and Charlotte Carolina Jones screws) had higher MFLs than the other screw designs tested. Conclusion: This study provides comparative fatigue strength data on larger screw diameters, which have not been previously reported. There was a statistically significant difference in screw fatigue properties at the screw diameters tested. Clinical Relevance: The clinical significance of this study is that it provides surgeons with fatigue strength data to aid in screw selection for Jones fracture fixation.

Research on Properties of Coastal Natural Spherical Aggregate Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 1810-1813
Author(s):  
Shuang Jian Jiao ◽  
Shuai Wang ◽  
Yong Guo
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Coastal Region ◽  
Fatigue Properties ◽  
Cement Concrete ◽  
Concrete Member ◽  
Spherical Aggregate ◽  
Cement Concrete Pavement ◽  
Engineering Significance ◽  
Stone Concrete

Our country has a long coastline and there are a lot of natural pebbles in coastal region. Applying natural pebbles in concrete is of great engineering significance and prospect. To measure the performance of coastal natural pebbles concrete and study the effect of aggregate on concrete properties, this article put forward a new comparison conditionthe same slump constant and cement dosage based on properties of coastal natural pebbles concrete and crushed stone concrete. Prepare different strength concrete under this condition. The compressive strength of pebble concrete is 100.5%110.7% times of stone concrete. The bending strength and fatigue strength are 97.8%108.1%, 135.8%176.6% respectively. This explains good static and fatigue properties of coastal natural pebbles. Pebble concrete has significant fatigue strength advantages in cement concrete pavement and concrete member under dynamic loading.

Research on Fatigue Properties of Grade B Steel Casted by the Resin Sand Process

2012 ◽  
Vol 189 ◽  
pp. 218-224 ◽  
Author(s):  
Nian Jun Fu ◽  
Ji Long Xie ◽  
Chang Wu Huang ◽  
Yao Teng
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
Survival Probability ◽  
Fatigue Properties ◽  
Group Method ◽  
Confidence Limits ◽  
Work Demand ◽  
Railway Freight ◽  
Probabilistic Evaluation ◽  
Load Conditions

Fatigue properties are investigated experimentally on grade B steel casted by the resin sand technology in this paper, which aims to study bolsters and side frames of Chinese railway freight cars. To begin with, cracked and non-cracked samples were tested by the group method respectively, and then the two obtained sets of experimental data were separately fitted through the three-parameter model with the conventional method. The influence of dispersion and the sample size on probabilistic evaluation was taken into consideration in terms of the cracked samples, and P (survival probability) -S -N curves as well as confidence limits were estimated. At the same time, by comparing the cracked samples’ median S-N curve with that of the non-cracked ones, we can know that this kind of cracks lower the fatigue strength of grade B steel. At last, the fatigue test that simulated real load conditions indicates that fatigue properties of bolsters and side frames by the resin sand process can meet the work demand in the future.

scholarly journals Bending Properties of Additively Manufactured Commercially Pure Titanium (CPTi) Limited Contact Dynamic Compression Plate (LC-DCP) Constructs: Effect of Surface Treatment

2021 ◽  
Author(s):  
Seungjong Lee ◽  
Nabeel Ahmad ◽  
Kayla Corriveau ◽  
Cameron Himel ◽  
Daniel Silva ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Dynamic Compression ◽  
Pure Titanium ◽  
Fatigue Properties ◽  
Single Shot ◽  
Structural Stiffness ◽  
Commercially Pure Titanium ◽  
Bending Tests ◽  
Bending Fatigue

Abstract BackgroundAdditive manufacturing of metallic materials, a layer-wise manufacturing method, is currently gaining attention in the biomedical industry because of its capability to fabricate complex geometries including customized parts fitting to patient requirements. However, one of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading. This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs. The results were compared with commercially manufactured (CM) counterparts.MethodsAM CPTi LC-DCP with different surface conditions including as-built, single shot-peened, dual shot-peened, and chemically assisted surface enhancement conditions and CM counterparts were mechanically tested based on ASTM International standard for metallic bone plates (ASTM F382). Bending stiffness, bending structural stiffness, and bending strength was measured by quasi-static bending tests, and bending fatigue properties were obtained by cyclic bending tests. ResultsBending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to CM counterparts; however, the bending strength of AM CPTi LC-DCPs is lower than CM counterparts. The fatigue strength of as-built AM CPTi LC-DCPs is lower compared to the CM counterparts. However, after post surface treatments, single shot-peened, dual shot-peened, and chemically assisted surface enhancement AM CPTi LC-DCPs exhibit statistically comparable fatigue strength to the CM CPTi LC-DCPs.ConclusionAM CPTi LC-DCP could be considered as an alternative to CM LC-DCP in applications that require less bending strength (~5.44 N·m). Post surface treatment should be considered on as-built implants to improve fatigue strength.

ARTICULATORY FEATURES OF THE /I/-TYPE VOWELS IN THE ALTAI-KIZHI DIALECT (MRI DATA)

2020 ◽  
pp. 43-50
Author(s):  
ALBINA A. DOBRININA ◽  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Experimental Data ◽  
Magnetic Resonance ◽  
Native Speakers ◽  
Literary Language ◽  
Resonance Imaging ◽  
Articulatory Features ◽  
The Common ◽  
Magnetic Resonance Imaging Mri ◽  
Rural Locality

The paper considers some articulatory features of allophones of the vowel /i/ in the Altai-Kizhi dialect (spoken in the locality Ust-Kan, Altai) of the Altai language visualized by magnetic resonance imaging (MRI). The Altai-Kizhi is the central basic dialect of the Altai literary language. In Altai, each rural locality represents a unique dialect, whose relevance of studying was emphasized by V. V. Radlov. Speech sounds of the /i/-type in the dialects of the Altai language are realized mainly as front variants with different degrees of openness. In the written Altai speech, the symbol “и” is used to denote narrow front non-labialized vowel; some variants of the Altai vowel /i/ are central-back differing in this from the Russian vowel /i/. Experimental data on the territorial dialects of the Altai-Kizhi dialect, obtained from its 6 native speakers (d1-d6) taking into account variable inherent palate height, shows both the common articulation bases of native speakers (clearly-expressed frontness) and their differences (variable openness).

scholarly journals Interpreting Locked Photographic Data: The Case of Apollo 17 Photo GPN-2000-00113

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Pyrrhon Amathes ◽  
Paul Christodoulides
Keyword(s):  
Experimental Data ◽  
Computer Simulations ◽  
The Moon ◽  
Geometrical Analysis ◽  
Apparent Position ◽  
Apollo Program ◽  
The Earth ◽  
Novel Approach ◽  
The World ◽  
The Moment

Photography can be used for pleasure and art but can also be used in many disciplines of science, because it captures the details of the moment and can serve as a proving tool due to the information it preserves. During the period of the Apollo program (1969 to 1972), the National Aeronautics and Space Administration (NASA) successfully landed humans on the Moon and showed hundreds of photos to the world presenting the travel and landings. This paper uses computer simulations and geometry to examine the authenticity of one such photo, namely Apollo 17 photo GPN-2000-00113. In addition, a novel approach is employed by creating an experimental scene to illustrate details and provide measurements. The crucial factors on which the geometrical analysis relies are locked in the photograph and are: (a) the apparent position of the Earth relative to the illustrated flag and (b) the point to which the shadow of the astronaut taking the photo reaches, in relation to the flagpole. The analysis and experimental data show geometrical and time mismatches, proving that the photo is a composite.

scholarly journals Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2171
Author(s):  
Armin Yousefi ◽  
Ahmad Serjouei ◽  
Reza Hedayati ◽  
Mahdi Bodaghi
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Element Model ◽  
Plastic Strain Amplitude ◽  
Friction Stir ◽  
Probe Hole ◽  
Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

scholarly journals Avoiding or restricting defectors in public goods games?

2015 ◽  
Vol 12 (103) ◽  
pp. 20141203 ◽  
Author(s):  
The Anh Han ◽  
Luís Moniz Pereira ◽  
Tom Lenaerts
Keyword(s):  
Experimental Data ◽  
Public Goods ◽  
Public Good ◽  
Common Good ◽  
Full Agreement ◽  
Group Interactions ◽  
The Common Good ◽  
Public Goods Games ◽  
The Common ◽  
Strategic Solution

When creating a public good, strategies or mechanisms are required to handle defectors. We first show mathematically and numerically that prior agreements with posterior compensations provide a strategic solution that leads to substantial levels of cooperation in the context of public goods games, results that are corroborated by available experimental data. Notwithstanding this success, one cannot, as with other approaches, fully exclude the presence of defectors, raising the question of how they can be dealt with to avoid the demise of the common good. We show that both avoiding creation of the common good, whenever full agreement is not reached, and limiting the benefit that disagreeing defectors can acquire, using costly restriction mechanisms, are relevant choices. Nonetheless, restriction mechanisms are found the more favourable, especially in larger group interactions. Given decreasing restriction costs, introducing restraining measures to cope with public goods free-riding issues is the ultimate advantageous solution for all participants, rather than avoiding its creation.

scholarly journals A NOTE ON PHASING LONG GENOMIC REGIONS USING LOCAL HAPLOTYPE PREDICTIONS

2006 ◽  
Vol 04 (03) ◽  
pp. 639-647 ◽  
Author(s):  
ELEAZAR ESKIN ◽  
RODED SHARAN ◽  
ERAN HALPERIN
Keyword(s):  
Large Scale ◽  
Computational Cost ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Novel Approach ◽  
Maximum Likelihood Criterion ◽  
The Common ◽  
Genomic Regions ◽  
High Computational Cost ◽  
Combining Information

The common approaches for haplotype inference from genotype data are targeted toward phasing short genomic regions. Longer regions are often tackled in a heuristic manner, due to the high computational cost. Here, we describe a novel approach for phasing genotypes over long regions, which is based on combining information from local predictions on short, overlapping regions. The phasing is done in a way, which maximizes a natural maximum likelihood criterion. Among other things, this criterion takes into account the physical length between neighboring single nucleotide polymorphisms. The approach is very efficient and is applied to several large scale datasets and is shown to be successful in two recent benchmarking studies (Zaitlen et al., in press; Marchini et al., in preparation). Our method is publicly available via a webserver at .

Kinetics of hypso anhydrites dissolution in water. Experimental studies

2019 ◽  
pp. 93-96
Author(s):  
A. L. Lebedev ◽  
I. V. Avilina
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Riccati Equation ◽  
Balance Equation ◽  
Experimental Studies ◽  
Common Ion ◽  
The Common ◽  
Common Ion Effect ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

Experimental study of kinetics of dissolution of hypso anhydrites at 25 ᵒC made it possible to formulate model of the process in the form of a balance equation for the kinetics of dissolution of gypsum, anhydrite (first and second orders, respectively) and kinetics of precipitation of gypsum (second order). The processing of the experimental data were carried out on the basis of the solution of the Riccati equation. When taking into account the common-ion effect on the solubility of gypsum and anhydrite, the calculated values turned out to be more comparable with the experimental ones.

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