Готові списки джерел за темами / Failure strength

Добірка наукової літератури з теми "Failure strength"

Автор: Grafiati

Опубліковано: 22 травня 2022

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Статті в журналах з теми "Failure strength":

Do, Thanh Trung, and Dong Joo Lee. "Failure of Composites with Discontinuous Fabric Preform under Bending." Key Engineering Materials 462-463 (January 2011): 698–703. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.698.

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During the fabric preform and/or mold closure processes of the resin transfer molded composites (RTMCs), the discontinuous fabric patterns such as wrinkling and overlapping can be occurred and influenced the failure strength. It is found that the composites with discontinuous fabric preform had two failure mechanisms as functions of fabric ply number and discontinuous fabric length under the three-point bending. First, the failure modes can be related to the bend strengths that were controlled by the interfacial bonding strength depending on the discontinuous fabric length. Second, the failures were controlled by the potential strength of fabric when the discontinuous length reached the critical value. Moreover, the experimentally measured results of the normal and discontinuous preform models under bending were compared to examine the safety conditions as functions of fiber content and other factors.

Mohammed, Ahmed, and Wael Mahmood. "Statistical Variations and New Correlation Models to Predict the Mechanical Behavior and Ultimate Shear Strength of Gypsum Rock." Open Engineering 8, no. 1 (August 11, 2018): 213–26. http://dx.doi.org/10.1515/eng-2018-0026.

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Abstract In this study, over 1000 data from the several research studies was used to characterize and compare the density, strengths, modulus, flexural strength, porosity and the ultimate shear strengths of the calcium rocks. The gypsum rock data were statistically analyzed, quantified and compared with the limestone rock data. The ranges of the densities for gypsum rock (CaSO4·2H2O) and limestone rock (CaCO3) were 2.10 to 2.83 gm/cm3 and 1.70 to 2.75 gm/cm3, respectively. The compressive and tensile strengths of the gypsum and limestone rocks varied from 2 MPa to 250 MPa and 1.8 MPa to 25 MPa, respectively. Vipulanandan correlation model was effective in relating the modulus of elasticity, flexural strength, with the relevant strengths of the rocks. A new nonlinear Vipulanandan failure criterion was developed to better quantify the tensile strength, pure shear (cohesion) strength and predict the maximum shear strength limit with applied normal stress on the gypsum and limestone rocks. The prediction of the failure models for the two rock types was also compared to the Mohr-Coulomb failure model. The Vipulanandan failure model predicted the maximum shear strength limit was, as the Mohr-Coulomb failure model does not have a limit on the maximum shear strength. With the Vipulanandan failure model based on the available data, the maximum shear strengths predicted for the gypsum and limestone rocks were 64 MPa and 114 MPa, respectively.

Liu, Zhun, Zhidong Guan, Riming Tan, Jifeng Xu, and Xing Li. "Multiscale Analysis of CFRP Laminates with MMF3 Criterion under Different Off-Axis Loading Conditions." Materials 11, no. 11 (November 12, 2018): 2255. http://dx.doi.org/10.3390/ma11112255.

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A multiscale analysis strategy with physical modified-micromechanics of failure (MMF3) criterion was proposed to analyze the failure behaviors of carbon fiber reinforced plastic (CFRP) laminates. The quantitative relationship between the macro- and micro- stresses was determined considering two typical fiber distributions. Thermal residual stress was taken into account in the stress transformation. The failures were defined and the properties of damaged elements were degraded at the constituent level. The back-calculation method based on the iteration algorithm was proposed to determine the micro strength with macro mechanical tests. A series of off-axis loading tests were conducted to verify the established multiscale models. The predicted strength was also compared with the results using micromechanics of failure (MMF) criterion to present accuracy improvements. Thermal residual stress was found to affect the strength by contributing to the matrix damage status. Meanwhile, sensitivity analysis was provided for the matrix-dominant micro strength to investigate its physical meaning. Results suggest that the micro tensile and compressive strength of the matrix influenced the off-axis tensile and compressive strengths respectively, with relative large off-axis angles, while the micro shear strength of the matrix dominated when the off-axis angles were relative small.

Winters, Katherine, Woodman Berry, Greg Seimens, and Oliver-Denzil Taylor. "Failure mode transitions of unconfined granular media from dry to unsaturated to “quasi-fully” saturated states." E3S Web of Conferences 195 (2020): 03023. http://dx.doi.org/10.1051/e3sconf/202019503023.

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Recent research has shown discrepancies between the prevailing mathematical representations of near-surface shear strength and the observed shear strengths. This investigation focuses on three granular materials, i.e., 1) poorly-graded, medium-fine silica-quartz sand, 2) an engineered silica-quartz mix of 3.38-mm and 0.638-mm sub-angular particles, and 3) an angular fused quartz sand. Specimens were tested under load-controlled conditions at variable saturations in order to identify and quantify the influence of suction on the granular structures and failure modes. All three materials exhibited localized radial particle force chain buckling failures in unconfined drained dry (UDκ) conditions and classical shear failures in the unconfined drained unsaturated shear (UDP) conditions. In unconfined drained suction failures (UDS) conditions, the poorly-graded, medium-fine silica-quartz sand exhibited a bulging and sloughing failure without weeping, while the other two materials wept and then held loads before failure. Thus, it is suggested that the pore fluid had a predominate lubrication (strength weakening) effect, and the assumption of structure stiffening (strength increase) from matric suction may not be valid at near-surface conditions for sub-angular silica-quartz materials but is valid for the angular fused quartz.

Sui, Zhi Li, Zhao Guang Li, Zhi Jun Yang, Ran Shen, Xu Peng Wang, and Wen Li Li. "Tunnel Strength and Excavation Effect under Different Stress Paths." Applied Mechanics and Materials 470 (December 2013): 902–6. http://dx.doi.org/10.4028/www.scientific.net/amm.470.902.

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The stress path division of soil strata surrounding the excavation tunnel was obtained by numerical simulation, and based on this, the impact variation of different stress paths to the surrounding soil strength was gotten by laboratory triaxial test. The results show that tunnel excavation can result in four different stress path divisions of the soil strata, which have deferent failure to the tunnel stability. Deferent paths have respective failure forms, and the failure strengths are basically the same when the forms are identical (extrusion failure or compression failure) even if the paths are different, but to deferent forms, the failure strength are deferent, generally speaking, the strength of extrusion failure will be 10% ~25% lower than that of compression failure. These researches can provide strong basis for accurately study about the influence of engineering property of environmental soil strata.

Bansal, Manik, Indra Vir Singh, Bhanu K. Mishra, Kamal Sharma, and IA Khan. "A numerical prediction of flexural strength probability for NBG-18 nuclear grade graphite using strength pair model." Journal of Strain Analysis for Engineering Design 52, no. 3 (March 17, 2017): 204–11. http://dx.doi.org/10.1177/0309324717698609.

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In this work, a strength pair model has been proposed for the numerical prediction of flexural strength probability of NBG-18 nuclear grade graphite. The input to the proposed model is a random strength pair of tensile and compressive strengths whose value is based on its probability of occurrence in the experimental data. A finite element–based deterministic numerical approach has been implemented. To account for the large difference in tensile and compressive strengths, Drucker–Prager failure criteria has been implemented. The failure envelope of the Drucker–Prager failure criteria is assumed to have uniaxial fit with Mohr–Coulomb model in the principal stress space. A total of 292 simulations with random pairs of tensile and compressive strength are performed on a three-point bend specimen to obtain a set of flexural strength data. The flexural strength data obtained through numerical simulations are fitted using normal and Weibull distributions. The flexural strength probability obtained from the proposed model is found on conservative side. A goodness-of-fit test concludes that Weibull distribution fits the numerical data better than normal distribution.

Cao, Rihong, Wenyu Tang, Hang Lin, and Xiang Fan. "Numerical Analysis for the Progressive Failure of Binary-Medium Interface under Shearing." Advances in Civil Engineering 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/4197172.

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Binary-medium specimens were fabricated using the particle flow code, and the shear strength, dilatancy, and failure behavior of the binary-medium specimens with different bond strength ratios (0.25, 0.5, 0.75, and 1.0) under different normal stresses were studied. Numerical results show that the bond strength ratio and normal stresses considerably influence the shear strengths of binary-medium interface. Shear strength increases as the bond strength ratio and normal stress increase. The dilation of interfaces with high bond strength ratios is more evident than those of interfaces with lower bond strength ratios, and the curves for the high bond strength ratio exhibit remarkable fluctuations during the residual stage. At increased normal stress and bond strength ratio, the peak dilation angle shows decreasing and increasing trends successively. In this study, the specimens exhibited three kinds of failure modes. In mode II, the sawtooth experienced shear failure, but some tensile cracks appeared on the interface of the binary-medium. In mode III, no sawtooth was cut off, indicating tensile failure on the interface. At a low bond strength ratio, damage or failure is mostly concentrated in the upper part of the model. Failure parts gradually transfer to the lower part of the model when the bond strength ratio and normal stress increase. Furthermore, evident tensile cracks occur on the interface. When the bond strength ratio reaches 1.0, the failure mode of the specimen gradually transforms from sheared-off failure to chip-off failure. The number of microcracks in the specimens indicates that the lower the bond strength ratio, the more severe the damage on the specimens.

Pang, Yu-Yang, Gang Wu, Zhi-Long Su, and Xiao-Yuan He. "Experimental study on the carbon-fiber-reinforced polymer–steel interfaces based on carbon-fiber-reinforced polymer delamination failures and hybrid failures." Advances in Structural Engineering 23, no. 11 (March 10, 2020): 2247–60. http://dx.doi.org/10.1177/1369433220911167.

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The failure mode is crucial to the interfacial bond performance between carbon-fiber-reinforced polymer plates and steel substrates. Existing studies mainly focused on the cohesive failures in the adhesive; however, research on other types of failure modes is still limited. In this article, a series of single-shear bonded joints are prepared to investigate the bond behaviors of the carbon-fiber-reinforced polymer–steel interfaces based on carbon-fiber-reinforced polymer delamination failures and hybrid failures. Three kinds of adhesives—which have different tensile strengths and elastic moduli—and two kinds of carbon-fiber-reinforced polymer plates—which have different interlaminar shear strengths—are used to evaluate the influencing factors of carbon-fiber-reinforced polymer–steel interfaces. The three-dimensional digital image correlation technique is applied to measure the strain and the displacement on the surface of each specimen. The obtained test results include the strain distribution, the ultimate load, the failure mode, the load–slip curves, and the bond–slip relationships. For the carbon-fiber-reinforced polymer delamination mode, the results show that the load at the debonding stage is closely related to the interlaminar shear strength of the carbon-fiber-reinforced polymer plate, and the higher the interlaminar shear strength is, the greater the load. However, for the hybrid mode, the load of the whole test process is independent of the interlaminar shear strength of the carbon-fiber-reinforced polymer plate.

Fang, Xuan, Jie Yang, Jia-Ming Na, and Zhen-Yuan Gu. "Unified Failure Strength Criterion for Terrace Slope Reinforcement Materials." Advances in Civil Engineering 2021 (October 14, 2021): 1–12. http://dx.doi.org/10.1155/2021/9639184.

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This paper presents a study on the failure strength criterion of terrace slope reinforcement materials, such as lean cemented sand and gravel (LCSG) material, under a triaxial stress state. Cement content and confining pressure were selected as major factors to investigate their influence on the peak stress of terrace slope reinforcement materials based on experimental results and data from the literature. The mechanical properties of the LCSG samples, with cement contents of 60, 80, and 90 kg/m3, and noncemented sand and gravel materials were tested under four confining pressure levels (namely, 300, 600, 1000, and 1500 kPa). The results show that the strength of LCSG material improves as the confining pressure increases. When the confining pressure exceeds 1200 kPa, the rate of increase of the strength for LCSG material and other cemented grained materials declines generally. The material strength displays a linear increase with the growth of the cement content. When the axial load rises up to a certain value, damage will occur at the particle cemented site near the shear plane, and the resistance stress generated by the cementation shows a trend of growth first and then attenuation, and concurrently, the friction between particles increases by degrees. Based on the identified strength characteristics of LCSG material under different cement contents and confining pressures, a new strength criterion that incorporates the frictional strengths and the cementing strengths is proposed for LCSG and other similar materials. The results of this work can provide an important theoretical basis for the stability calculation of terrace slopes and LCSG dams.

Marone, Chris. "Fault zone strength and failure criteria." Geophysical Research Letters 22, no. 6 (March 15, 1995): 723–26. http://dx.doi.org/10.1029/95gl00268.

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Дисертації з теми "Failure strength":

Weernink, Corinne M. "Heart failure and respiratory muscle strength." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0001/MQ42222.pdf.

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Björklund, Oscar. "Ductile Failure in High Strength Steel Sheets." Doctoral thesis, Linköpings universitet, Hållfasthetslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-105213.

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Developments in computer-aided engineering and the rapid growth of computational power have made simulation-driven process and product development efficient and useful since it enables detailed evaluation of product designs and their manufacturing processes. In the context of a sheet metal component, it is vital to predict possible failure both during its forming process and its subsequent usage. Accurate numerical models are needed in order to obtain trustworthy simulation results. Furthermore, the increasing demands imposed on improved weight-to-performance ratio for many products endorse the use of high-strength steels. These steels often show anisotropic behaviour and more complex hardening and fracturing compared to conventional steels. Consequently, demand for research on material and failure models suitable for these steels has increased. In this work, the mechanical and fracture behaviour of two high-strength steels, Docol 600DP and Docol 1200M, have been studied under various deformation processes. Experimental results have been used both for material characterisation and for calibration of fracture criteria. One major requirement as concerns the fracture criteria studied is that they should be simple to apply in industrial applications, i.e. it should be possible to easily calibrate the fracture criteria in simple mechanical experiments and they should be efficient and accurate. Consequently, un-coupled phenomenological damage models have been the main focus throughout this work. Detailed finite element models including accurate constitutive laws have be used to predict and capture material instabilities. Most of the fracture criteria studied are modifications of the plastic work to fracture. Ductile tensile and ductile shear types of fracture are of particular interest in sheet metal applications. For these fractures the modification of the plastic work relates to void coalescence and void collapse, respectively. Anisotropy in fracture behaviour can be captured by the introduction of a material directional function. The dissertation consists of two parts. The first part contains theory and background. The second consists of five papers.

Farrell, Robert William. "Structural Features Related to Tree Crotch Strength." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32619.

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Crotches were cut out of red maple (Acer rubrum), callery pear (Pyrus calleryana), and sawtooth oak (Quercus acutissima) trees (2.5â -7â d.b.h.) and then pulled apart in an engineering testing machine to identify physical parameters correlated with crotch strength. Parameters measured included the diameter of the branch and of the trunk above and below the crotch, angle of the branch and branch bark ridge, and the length of the crotch and the branch bark ridge. The force required to break each sample was used to calculate breaking strength based on the formula for bending stress. Each parameter was tested for correlation with crotch strength within the individual species and for the three species combined. The ratio of branch diameter over crotch width had the highest correlation coefficient for crotch strength. Branch angle was also correlated with crotch strength but not as highly as the ratio of the diameters. V-shaped crotches (those with included bark) were significantly weaker than U-shaped crotches for all species. The ratio of the two stem diameters greatly influenced the manner in which the crotches broke. In crotches where the branch diameter was 2/3 the size of the trunk or smaller, the crotch broke by being pulled directly out of the trunk. Crotches with branches more than 2/3 the diameter of the trunk broke when the trunk split longitudinally and had significantly lower strength values. These results indicate that increased crotch strength results from a small branch diameter relative to that of the trunk.
Master of Science

Björklund, Oscar. "Modelling of Failure in High Strength Steel Sheets." Licentiate thesis, Linköpings universitet, Hållfasthetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-77759.

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In this theses the high strength steel Docol 600DP and the ultra high strength steel Docol 1200M are studied. Constitutive laws and failure models are calibrated and veried by the use of experiments and numerical simulations. For the constitutive equations, an eight parameter high exponent yield surface has been adopted, representing the anisotropic behaviour, and a mixed isotropic-kinematic hardening has been used to capture non-linear strain paths. For ductile sheet metals three dierent failure phenomena have been observed: (i) ductile fracture, (ii) shear fracture, and (iii) instability with localised necking. The models for describing the dierent failure types have been chosen with an attempt to use just a few tests in addition to these used for the constitutive model. In this work the ductile and shear fracture have been prescribed by models presented by Cockroft-Latham and Bressan-Williams, respectively. The instability phenomenon is described by the constitutive law and the nite element models. The results obtained are in general in good agreement with test results. The thesis is divided into two main parts. The background, theoretical framework, mechanical experiments and nite element models are presented in the rst part. In the second part, two papers are appended.

In publication incorrect ISBN: 9789175198955

De-Vilder, Saskia Joan. "Controls on the evolution of strength and failure style in shallow rock slope failures." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12819/.

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Rock fall failure comprises fracturing through zones of intact rock, known as rock bridges, and kinematic release along discontinuity surfaces. Understanding controls on magnitude – frequency relationships of rockfalls, and their associated failure characteristics aids susceptibility analysis and interpretation of pre-failure deformation. For failure to occur, these rock bridges must have been weakened, with this damage accumulation driven by a suite of weathering processes. This thesis aims to explore the spatial and temporal controls on weathering induced strength degradation and its subsequent influence on the mechanics of rockfall detachment. Within this, it examines the role of gravitational ambient stress, as dictated by slope topography and rock mass structure, which recent research suggests influences the efficiency of weathering processes. The project integrates field observations, analogue experiments and numerical modelling over varying spatial scales. Terrestrial laser scanning and gigapixel photography are combined to forensically map rock bridge attributes within rockfall detachment surfaces. The role of slope geometry and rock mass structure in concentrating stress is assessed via conceptual finite element models. Finally, samples are subjected to stress conditions induced by the slope structure and environmental conditions in a series of weathering analogue experiments. Together, these results indicate that weathering significantly reduces intact rock strength with areas of stress concentration purely a mechanical control on rockfall release rather than a temporal control on weakening. Weaker rock is characterised by substantial post-peak strength, which requires multiple stages of brittle fracture before ultimate failure occurs. This in turn influences the stages of failure required through rock bridges before final failure, with this number of rock bridges dependent on rockfall size. Mechanically, failure mode is dependent on rock bridge proportion, distribution and location for individual rockfalls. A conceptual model describes magnitude-frequency characteristics and the observable pattern of pre-failure deformation expected for different stages of weathering.

Alkhalil, M. F. S. "Strength of filament wound structures under complex stresses." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387260.

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Prasad, Hanasoge Saraswathi Deepthi. "Bearing strength and failure behavior of hybrid composite laminates." Thesis, Linköpings universitet, Konstruktionsmaterial, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-170914.

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Composite layups have been continuously used over many years in various applications. It is necessary to optimize its composition by studying various parameters influencing the mechanical properties and studying the failure behavior. In this master thesis, the objective was to test five different plies manufactured using thick and thin plies and various combinations of thick and thin laminates called hybrid laminates. Bearing tests are performed for five layups with each layer has its thickness varying from 40μm to 130μm, and a combination called hybrid laminate, and the results from the tests are investigated. The resulting system has a good performance with onset damage above 700 MPa and an ultimate failure above 1130 MPa, using fibers' full potential. Also, the different failure modes like fiber kinking, matrix crack, delamination, and their effect on the layup's strength are investigated using fractography. This paper also investigates the influences of the thickness of the laminate on the strength of hybrid composites jointed using different mechanisms, and its failure modes are checked. Results from this experiment are used to validate in the form of FEM model, which is a part of an internal project at RISE SICOMP AB. This thesis is suitable for an engineering student in mechanical engineering, material science interested in composite materials and fractography.

Noury, Pourya. "On failure of high strength steel bridge roller bearings." Doctoral thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65215.

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This thesis is concerned with failure analysis of high strength steel bridge roller bearings.Paper Adescribes how the commonly used Hertz formulas for contact stresses underestimate the actual stresses in practice due to temperature differences, misalignments and other construction-related conditions. In this paper, finite element analyses of bridge roller bearings were carried out to investigate the accuracy of the traditional roller bearing design rules in view of issues such as girder deformability, misalignment imperfections and material nonlinearity. The results first indicated that roller bearings develop contact stress concentrations at the outer edges of the rollers. Second, it was shown that the contact stresses are very sensitive to misalignment imperfections between the bridge girder and the abutment. Third, it was shown that the roller bearings develop inelastic deformation at relatively low loads in relation to the design load.In Paper B, the finite element method was employed to gain an understanding of the behaviour of a cracked bridge roller bearing in service. The cracked roller was considered as a two-dimensional edge-cracked disk subjected to a diametrical compressive line load. The crack parameters, stress intensity factor Mode I, KI and Mode II ,KII were calculated for the relevant load configuration and angle of disk rotation. The calculated data for KIwere also used to check the accuracy of approximate stress intensity factor solutions reported earlier for Mode I. For plain Mode I loading very good agreement was found between the obtained results and data presented in Schindler and Morf (1994). Paper Cis aimed at finding the likely failure mechanism of a bridge roller bearing made of high strength martensitic stainless steel. Spectroscopy and finite element stress analysis of the roller indicated that an initial radial surface crack, found at an end face of the roller and close to the contact region, was induced by stress corrosion cracking (SCC). The initial crack subsequently changed shape and increased in size under growth through fatigue and finally formed a quarter-circle radial crack centred on the end face corner of the roller. Numerically computed stress intensity factors for the final crack showed that crack loading was predominantly in Mode II. For a crack size as observed on the fracture surface, the maximum service load, as specified by the manufacturer, enhanced by a certain roller bearing misalignment effect, was sufficient for failure through fracture.InPaper D, after a brief summary of the history of high strength stainless steel bearings, the paper reviews service experience of failed bearings in Sweden and elsewhere. Accompanying finite element analyses were performed in order to gain better insight into the likely failure mechanism. Finally, thiscomprehensive review leads to a conclusion that identifies the causes of the failures occurred and makes some recommendations.

Zhang, Xuesong, and n/a. "Punching Shear Failure Analysis of Reinforced Concrete Flat Plates Using Simplified Ust Failure Criterion." Griffith University. School of Engineering, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20051104.153239.

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Failure criteria play a vital role in the numerical analysis of reinforced concrete structures. The current failure criteria can be classified into two types, namely the empirical and theoretical failure criteria. Empirical failure criteria normally lack reasonable theoretical backgrounds, while theoretical ones either involve too many parameters or ignore the effects of intermediate principal stress on the concrete strength. Based on the octahedral shear stress model and the concrete tensile strength under the state of triaxial and uniaxial stress, a new failure criterion, that is, the simplified unified strength theory (UST), is developed by simplifiing the five-parameter UST for the analysis of reinforced concrete structures. According to the simplified UST failure criterion, the concrete strength is influenced by the maximum and intermediate principal shear stresses together with the corresponding normal stresses. Moreover, the effect of hydrostatic pressure on the concrete strength is also taken into account. The failure criterion involves three concrete strengths, namely the uniaxial tensile and compressive strengths and the equal biaxial compressive strength. In the numerical analysis, a degenerated shell element with the layered approach is adopted for the simulation of concrete structures. In the layered approach, concrete is divided into several layers over the thickness of the elements and reinforcing steel is smeared into the corresponding number of layers of equivalent thickness. In each concrete layer, three-dimensional stresses are calculated at the integration points. For the material modelling, concrete is treated as isotropic material until cracking occurs. Cracked concrete is treated as an orthotropic material incorporating tension stiffening and the reduction of cracked shear stiffness. Meanwhile, the smeared craclc model is employed. The bending reinforcements and the stirrups are simulated using a trilinear material model. To verify the correctness of the simplified UST failure criterion, comparisons are made with concrete triaxial empirical results as well as with the Kupfer and the Ottosen failure criteria. Finally, the proposed failure criterion is used for the flexural analysis of simply supported reinforced concrete beams. Also conducted are the punching shear analyses of single- and multi-column-slab connections and of half-scale flat plate models. In view of its accuracy and capabilities, the simplified UST failure criterion may be used to analyse beam- and slab-type reinforced concrete structures.

Colavito, Kyle Wesley. "Peridynamics for Failure and Residual Strength Prediction of Fiber-Reinforced Composites." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311300.

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Peridynamics is a reformulation of classical continuum mechanics that utilizes integral equations in place of partial differential equations to remove the difficulty in handling discontinuities, such as cracks or interfaces, within a body. Damage is included within the constitutive model; initiation and propagation can occur without resorting to special crack growth criteria necessary in other commonly utilized approaches. Predicting damage and residual strengths of composite materials involves capturing complex, distinct and progressive failure modes. The peridynamic laminate theory correctly predicts the load redistribution in general laminate layups in the presence of complex failure modes through the use of multiple interaction types.This study presents two approaches to obtain the critical peridynamic failure parameters necessary to capture the residual strength of a composite structure. The validity of both approaches is first demonstrated by considering the residual strength of isotropic materials. The peridynamic theory is used to predict the crack growth and final failure load in both a diagonally loaded square plate with a center crack, as well as a four-point shear specimen subjected to asymmetric loading.This study also establishes the validity of each approach by considering composite laminate specimens in which each failure mode is isolated. Finally, the failure loads and final failure modes are predicted in a laminate with various hole diameters subjected to tensile and compressive loads.

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Книги з теми "Failure strength":

Kolff, Willem J., Belding H. Scribner, Thomas Starzl, and Eli A. Friedman. Strength and Compassion in Kidney Failure. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5296-9.

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Kim, A. Probability of brittle failure. [Washington, DC: National Aeronautics and Space Administration, 1991.

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Asian Peasant Women Dialogue on the General Agreement on Trade and Tariffs and Structural Adjustment Programs (1992 Antipolo, Philippines). Their failure becomes our strength: Conference proceedings. [Manila]: The Federation, 1992.

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Theocaris, Pericles S. On a general theory of failure for the anisotropic matter. Athēnai: Grapheion Dēmosieumatōn tēs Akadēmias Athēnōn, 1997.

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Naik, Rajiv A. Ply-level failure analysis of a graphite/epoxy laminate under bearing-bypass loading. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1988.

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Hahn, H. Thomas. Compression failure mechanisms of composite structures. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Branch, 1986.

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International Symposium on Pre-Failure Deformation Characteristics of Geomaterials (1994 Sapporo, Japan). Pre-failure deformation of geomaterials: Proceedings of the International Symposium on Pre-Failure Deformation Characteristics of Geomaterials, Sapporo, Japan 12-14 September 1994. Rotterdam: A.A. Balkema, 1994.

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Ashour, Mohamed. Pile group program for full material modeling and progressive failure: Final report. Sacramento, Calif.]: California Dept. of Transportation, Division of Research and Innovation, 2008.

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Johnson, Eric R. Compression strength failure mechanisms in unidirectional composite laminates containing a hole: Final report. Blacksburg, Va: Dept. of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, 1993.

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Yang, Sheng-Qi. Strength Failure and Crack Evolution Behavior of Rock Materials Containing Pre-existing Fissures. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-47303-0.

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Частини книг з теми "Failure strength":

da Silva, Lucas F. M. "Failure Strength Tests." In Handbook of Adhesion Technology, 443–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-01169-6_19.

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da Silva, Lucas F. M., R. J. C. Carbas, and M. D. Banea. "Failure Strength Tests." In Handbook of Adhesion Technology, 1–33. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-42087-5_19-2.

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da Silva, Lucas F. M., Ricardo J. C. Carbas, and Mariana D. Banea. "Failure Strength Tests." In Handbook of Adhesion Technology, 489–521. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-55411-2_19.

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Sexauer, W. P., G. J. Criner, and S. G. Kelsen. "Assessment of Respiratory Muscle Strength." In Ventilatory Failure, 97–124. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-84554-3_7.

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Singh, D. K. "Theory of Elastic Failure." In Strength of Materials, 433–58. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59667-5_10.

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Leckie, Frederick A., and Dominic J. Dal Bello. "Failure Criteria." In Strength and Stiffness of Engineering Systems, 1–15. Boston, MA: Springer US, 2008. http://dx.doi.org/10.1007/978-0-387-49474-6_9.

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Gould, Phillip L. "Strength and Failure Criteria." In Introduction to Linear Elasticity, 309–30. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-4833-4_12.

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Gould, Phillip L., and Yuan Feng. "Strength and Failure Criteria." In Introduction to Linear Elasticity, 325–49. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73885-7_12.

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Gould, Phillip L. "Strength and Failure Criteria." In Introduction to Linear Elasticity, 202–22. New York, NY: Springer New York, 1994. http://dx.doi.org/10.1007/978-1-4612-4296-3_11.

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Vinson, J. R., and R. L. Sierakowski. "Strength and Failure Theories." In The behavior of structures composed of composite materials, 209–38. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-5187-7_7.

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Тези доповідей конференцій з теми "Failure strength":

Li, Weiming. "Failure Analysis on Insufficient ACF Bonding Strength." In 2018 19th International Conference on Electronic Packaging Technology (ICEPT). IEEE, 2018. http://dx.doi.org/10.1109/icept.2018.8480766.

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Dzioba, I., and S. Lipiec. "Microstructure, strength properties and fracture toughness of S355JR steel." In FATIGUE FAILURE AND FRACTURE MECHANICS XXVI: Proceedings of the XXVI Polish National Conference on Fatigue Failure and Fracture Mechanics. Author(s), 2016. http://dx.doi.org/10.1063/1.4965948.

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Wen-hui Tan and Ya-liang Li. "Influence of component shear strength on rock failure." In 2010 2nd International Conference on Information Science and Engineering (ICISE). IEEE, 2010. http://dx.doi.org/10.1109/icise.2010.5689820.

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Gregory, Garry H., and Kristi K. Bumpas. "Post-Peak Fully-Softened Strength and Curved Strength Envelope in Shallow Slope Failure Analysis." In Geo-Congress 2013. Reston, VA: American Society of Civil Engineers, 2013. http://dx.doi.org/10.1061/9780784412787.026.

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Masuyama, F., and N. Komai. "Creep Failure Behavior of Creep-Strength Enhanced Ferritic Steels." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2577.

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Creep-strength enhanced ferritic steels such as Gr.92, Gr.122, Gr.23 and Gr.91 have recently been introduced for power plant applications, and some of these have experienced creep failure in boiler tubes and thick wall components after several years of operation. In order to use these steels safely in power plants, understanding of creep failure behavior is essential. In this study the creep failure of Gr.91 and Gr.92 boiler tube base metal and Type IV cracking of Gr.92, Gr.122, Gr.23 and Gr.91 welds were reproduced in test piece of actual components size. Creep failure mode was investigated, as was microstructural morphology during creep, particularly in the weldment, with discussion based on evidence of void formation and changes in the physical damage in terms of creep life.

Kato, Masana, Gang Deng, Masashi Yamanaka, Ryoji Yamamoto, Noboru Ono, and Katsumi Inoue. "Fatigue Failure and Strength Evaluation of Traction Drive Rollers." In ASME 2000 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/detc2000/ptg-14377.

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Abstract The surface fatigue failures of the traction drive rollers are different to that of gears and bearings because of the high traction force, skew and small slip ratio. In this research, fatigue tests of traction rollers were performed in different slip ratios and skew angles. The effects of running conditions on the fatigue lives of traction drive rollers are clarified and explained based on the surface crack growth and wear situations. Although a higher slip ratio will make a lower fatigue life, the fatigue strength will increase inversley under the skew conditions, because of the differences in mechanical and tribological condition for surface crack growth and the severe surface wear, which diminishes the surface crack length. For evaluation of the effects of such as slip ratio and skew on the fatigue strength of traction rollers, a new method is put forward in which the relationship between the surface temperature index and fatigue life is used instead of S-N curve.

COEVELD, E. M., J. G. KNOEFF, A. BIZARRI, and M. KLEIN BRETELER. "RESIDUAL STRENGTH OF DIKE AFTER FAILURE OF COVER LAYER." In Proceedings of the 29th International Conference. World Scientific Publishing Company, 2005. http://dx.doi.org/10.1142/9789812701916_0282.

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Skontorp, Arne. "Strength and failure mechanisms of polyimide-coated optical fibers." In SPIE's 7th Annual International Symposium on Smart Structures and Materials, edited by Richard O. Claus and William B. Spillman, Jr. SPIE, 2000. http://dx.doi.org/10.1117/12.388112.

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Kwon, S., D. Vassalos, and G. Mermiris. "Progressive Structural Failure and Residual Strength of Damaged Ships." In The Damaged Ship. RINA, 2011. http://dx.doi.org/10.3940/rina.ds.2011.11.

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"Fiber Reinforced High Strength Concrete: Evaluation fo Failure Mechanism." In "SP-207: Proceedings, Third International Conference on High Performance Concrete: Performance and Quality of Concrete St". American Concrete Institute, 2002. http://dx.doi.org/10.14359/12383.

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Звіти організацій з теми "Failure strength":

Tang, P. Y. Development of a Progressive Failure Model for Strength of Laminated Composite Structure. Fort Belvoir, VA: Defense Technical Information Center, November 1989. http://dx.doi.org/10.21236/ada216966.

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Krause, Ralph F. Jr. Proposed ASTM standard test method for elevated temperature flexural strength, creep strain, and creep time to failure for advanced ceramics. Gaithersburg, MD: National Institute of Standards and Technology, 1989. http://dx.doi.org/10.6028/nist.ir.89-4127.

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Bathon, Leander. Probabilistic Determination of Failure Load Capacity Variations for Lattice Type Structures Based on Yield Strength Variations including Nonlinear Post-Buckling Member Performance. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.1224.

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Al-Qadi, Imad, Qingqing Cao, Lama Abufares, Siqi Wang, Uthman Mohamed Ali, and Greg Renshaw. Moisture Content and In-place Density of Cold-Recycling Treatments. Illinois Center for Transportation, May 2022. http://dx.doi.org/10.36501/0197-9191/22-007.

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Cold-recycling treatments are gaining popularity in the United States because of their economic and environmental benefits. Curing is the most critical phase for these treatments. Curing is the process where emulsion breaks and water evaporates, leaving residual binder in the treated material. In this process, the cold-recycled mix gains strength. Sufficient strength is required before opening the cold-treated layer to traffic or placing an overlay. Otherwise, premature failure, related to insufficient strength and trapped moisture, would be expected. However, some challenges arise from the lack of relevant information and specifications to monitor treatment curing. This report presents the outcomes of a research project funded by the Illinois Department for Transportation to investigate the feasibility of using the nondestructive ground-penetrating radar (GPR) for density and moisture content estimation of cold-recycled treatments. Monitoring moisture content is an indicator of curing level; treated layers must meet a threshold of maximum allowable moisture content (2% in Illinois) to be considered sufficiently cured. The methodology followed in this report included GPR numerical simulations and GPR indoor and field tests for data sources. The data were used to correlate moisture content to dielectric properties calculated from GPR measurements. Two models were developed for moisture content estimation: the first is based on numerical simulations and the second is based on electromagnetic mixing theory and called the Al-Qadi-Cao-Abufares (ACA) model. The simulation model had an average error of 0.33% for moisture prediction for five different field projects. The ACA model had an average error of 2% for density prediction and an average root-mean-square error of less than 0.5% for moisture content prediction for both indoor and field tests. The ACA model is presented as part of a developed user-friendly tool that could be used in the future to continuously monitor curing of cold-recycled treatments.

Shmulevich, Itzhak, Shrini Upadhyaya, Dror Rubinstein, Zvika Asaf, and Jeffrey P. Mitchell. Developing Simulation Tool for the Prediction of Cohesive Behavior Agricultural Materials Using Discrete Element Modeling. United States Department of Agriculture, October 2011. http://dx.doi.org/10.32747/2011.7697108.bard.

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The underlying similarity between soils, grains, fertilizers, concentrated animal feed, pellets, and mixtures is that they are all granular materials used in agriculture. Modeling such materials is a complex process due to the spatial variability of such media, the origin of the material (natural or biological), the nonlinearity of these materials, the contact phenomenon and flow that occur at the interface zone and between these granular materials, as well as the dynamic effect of the interaction process. The lack of a tool for studying such materials has limited the understanding of the phenomena relevant to them, which in turn has led to energy loss and poor quality products. The objective of this study was to develop a reliable prediction simulation tool for cohesive agricultural particle materials using Discrete Element Modeling (DEM). The specific objectives of this study were (1) to develop and verify a 3D cohesionless agricultural soil-tillage tool interaction model that enables the prediction of displacement and flow in the soil media, as well as forces acting on various tillage tools, using the discrete element method; (2) to develop a micro model for the DEM formulation by creating a cohesive contact model based on liquid bridge forces for various agriculture materials; (3) to extend the model to include both plastic and cohesive behavior of various materials, such as grain and soil structures (e.g., compaction level), textures (e.g., clay, loam, several grains), and moisture contents; (4) to develop a method to obtain the parameters for the cohesion contact model to represent specific materials. A DEM model was developed that can represent both plastic and cohesive behavior of soil. Soil cohesive behavior was achieved by considering tensile force between elements. The developed DEM model well represented the effect of wedge shape on soil behavior and reaction force. Laboratory test results showed that wedge penetration resistance in highly compacted soil was two times greater than that in low compacted soil, whereas DEM simulation with parameters obtained from the test of low compacted soil could not simply be extended to that of high compacted soil. The modified model took into account soil failure strength that could be changed with soil compaction. A three dimensional representation composed of normal displacement, shear failure strength and tensile failure strength was proposed to design mechanical properties between elements. The model based on the liquid bridge theory. An inter particle tension force measurement tool was developed and calibrated A comprehensive study of the parameters of the contact model for the DEM taking into account the cohesive/water-bridge was performed on various agricultural grains using this measurement tool. The modified DEM model was compared and validated against the test results. With the newly developed model and procedure for determination of DEM parameters, we could reproduce the high compacted soil behavior and reaction forces both qualitatively and quantitatively for the soil conditions and wedge shapes used in this study. Moreover, the effect of wedge shape on soil behavior and reaction force was well represented with the same parameters. During the research we made use of the commercial PFC3D to analyze soil tillage implements. An investigation was made of three different head drillers. A comparison of three commonly used soil tillage systems was completed, such as moldboard plow, disc plow and chisel plow. It can be concluded that the soil condition after plowing by the specific implement can be predicted by the DEM model. The chisel plow is the most economic tool for increasing soil porosity. The moldboard is the best tool for soil manipulation. It can be concluded that the discrete element simulation can be used as a reliable engineering tool for soil-implement interaction quantitatively and qualitatively.

Uhl, Stacey, Shazia Mehmood Siddique, Liam McKeever, Aaron Bloschichak, Kristen D’Anci, Brian Leas, Nikhil K. Mull, and Amy Y. Tsou. Malnutrition in Hospitalized Adults: A Systematic Review. Agency for Healthcare Research and Quality (AHRQ), October 2021. http://dx.doi.org/10.23970/ahrqepccer249.

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Objectives. To review the association between malnutrition and clinical outcomes among hospitalized patients, evaluate effectiveness of measurement tools for malnutrition on clinical outcomes, and assess effectiveness of hospital-initiated interventions for patients diagnosed with malnutrition. Data sources. We searched electronic databases (Embase®, MEDLINE®, PubMed®, and the Cochrane Library) from January 1, 2000, to June 3, 2021. We hand-searched reference lists of relevant studies and searched for unpublished studies in ClinicalTrials.gov. Review methods. Using predefined criteria and dual review, we selected (1) existing systematic reviews (SRs) to assess the association between malnutrition and clinical outcomes, (2) randomized and non-randomized studies to evaluate the effectiveness of malnutrition tools on clinical outcomes, and (3) randomized controlled trials (RCTs) to assess effectiveness of hospital-initiated treatments for malnutrition. Clinical outcomes of interest included mortality, length of stay, 30-day readmission, quality of life, functional status, activities of daily living, hospital acquired conditions, wound healing, and discharge disposition. When appropriate, we conducted meta-analysis to quantitatively summarize study findings; otherwise, data were narratively synthesized. When available, we used pooled estimates from existing SRs to determine the association between malnutrition and clinical outcomes, and assessed the strength of evidence. Results. Six existing SRs (including 43 unique studies) provided evidence on the association between malnutrition and clinical outcomes. Low to moderate strength of evidence (SOE) showed an association between malnutrition and increased hospital mortality and prolonged hospital length of stay. This association was observed across patients hospitalized for an acute medical event requiring intensive care unit care, heart failure, and cirrhosis. Literature searches found no studies that met inclusion criteria and assessed effectiveness of measurement tools. The primary reason studies did not meet inclusion criteria is because they lacked an appropriate control group. Moderate SOE from 11 RCTs found that hospital-initiated malnutrition interventions likely reduce mortality compared with usual care among hospitalized patients diagnosed with malnutrition. Low SOE indicated that hospital-initiated malnutrition interventions may also improve quality of life compared to usual care. Conclusions. Evidence shows an association between malnutrition and increased mortality and prolonged length of hospital stay among hospitalized patients identified as malnourished. However, the strength of this association varied depending on patient population and tool used to identify malnutrition. Evidence indicates malnutrition-focused hospital-initiated interventions likely reduce mortality and may improve quality of life compared to usual care among patients diagnosed with malnutrition. Research is needed to assess the clinical utility of measurement tools for malnutrition.

Saldanha, Ian J., Wangnan Cao, Justin M. Broyles, Gaelen P. Adam, Monika Reddy Bhuma, Shivani Mehta, Laura S. Dominici, Andrea L. Pusic, and Ethan M. Balk. Breast Reconstruction After Mastectomy: A Systematic Review and Meta-Analysis. Agency for Healthcare Research and Quality (AHRQ), July 2021. http://dx.doi.org/10.23970/ahrqepccer245.

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Objectives. This systematic review evaluates breast reconstruction options for women after mastectomy for breast cancer (or breast cancer prophylaxis). We addressed six Key Questions (KQs): (1) implant-based reconstruction (IBR) versus autologous reconstruction (AR), (2) timing of IBR and AR in relation to chemotherapy and radiation therapy, (3) comparisons of implant materials, (4) comparisons of anatomic planes for IBR, (5) use versus nonuse of human acellular dermal matrices (ADMs) during IBR, and (6) comparisons of AR flap types. Data sources and review methods. We searched Medline®, Embase®, Cochrane CENTRAL, CINAHL®, and ClinicalTrials.gov from inception to March 23, 2021, to identify comparative and single group studies. We extracted study data into the Systematic Review Data Repository Plus (SRDR+). We assessed the risk of bias and evaluated the strength of evidence (SoE) using standard methods. The protocol was registered in PROSPERO (registration number CRD42020193183). Results. We found 8 randomized controlled trials, 83 nonrandomized comparative studies, and 69 single group studies. Risk of bias was moderate to high for most studies. KQ1: Compared with IBR, AR is probably associated with clinically better patient satisfaction with breasts and sexual well-being but comparable general quality of life and psychosocial well-being (moderate SoE, all outcomes). AR probably poses a greater risk of deep vein thrombosis or pulmonary embolism (moderate SoE), but IBR probably poses a greater risk of reconstructive failure in the long term (1.5 to 4 years) (moderate SoE) and may pose a greater risk of breast seroma (low SoE). KQ 2: Conducting IBR either before or after radiation therapy may result in comparable physical well-being, psychosocial well-being, sexual well-being, and patient satisfaction with breasts (all low SoE), and probably results in comparable risks of implant failure/loss or need for explant surgery (moderate SoE). We found no evidence addressing timing of IBR or AR in relation to chemotherapy or timing of AR in relation to radiation therapy. KQ 3: Silicone and saline implants may result in clinically comparable patient satisfaction with breasts (low SoE). There is insufficient evidence regarding double lumen implants. KQ 4: Whether the implant is placed in the prepectoral or total submuscular plane may not be associated with risk of infections that are not explicitly implant related (low SoE). There is insufficient evidence addressing the comparisons between prepectoral and partial submuscular and between partial and total submuscular planes. KQ 5: The evidence is inconsistent regarding whether human ADM use during IBR impacts physical well-being, psychosocial well-being, or satisfaction with breasts. However, ADM use probably increases the risk of implant failure/loss or need for explant surgery (moderate SoE) and may increase the risk of infections not explicitly implant related (low SoE). Whether or not ADM is used probably is associated with comparable risks of seroma and unplanned repeat surgeries for revision (moderate SoE for both), and possibly necrosis (low SoE). KQ 6: AR with either transverse rectus abdominis (TRAM) or deep inferior epigastric perforator (DIEP) flaps may result in comparable patient satisfaction with breasts (low SoE), but TRAM flaps probably increase the risk of harms to the area of flap harvest (moderate SoE). AR with either DIEP or latissimus dorsi flaps may result in comparable patient satisfaction with breasts (low SoE), but there is insufficient evidence regarding thromboembolic events and no evidence regarding other surgical complications. Conclusion. Evidence regarding surgical breast reconstruction options is largely insufficient or of only low or moderate SoE. New high-quality research is needed, especially for timing of IBR and AR in relation to chemotherapy and radiation therapy, for comparisons of implant materials, and for comparisons of anatomic planes of implant placement.

Seery, Emma, Anna Marriott, Katie Malouf Bous, and Rebecca Shadwick. From Catastrophe to Catalyst: Can the World Bank make COVID-19 a turning point for building universal and fair public healthcare systems? Oxfam, December 2020. http://dx.doi.org/10.21201/2020.6928.

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COVID-19 has exposed the widespread failure to invest in strong and universal public health systems, putting millions of lives at risk and dramatically widening health inequalities. Oxfam analysed the World Bank’s emergency health funding to 71 countries in response to the pandemic. While its response has been rapid and significant, Oxfam finds that the World Bank has missed vital opportunities to strengthen public health systems so they can tackle COVID-19 and deliver health for all in the future. The research outlined in this briefing finds that 89% of World Bank projects do not plan to support any action to remove financial barriers, including user fees, that exclude millions from life-saving care; and two-thirds lack any plans to increase the number of healthcare workers. An urgent course correction is needed to help countries effectively fight the pandemic and build fairer, more resilient universal healthcare systems.

Doyle, Jesse D., Nolan R. Hoffman, and M. Kelvin Taylor. Aircraft Arrestor System Panel Joint Improvement. U.S. Army Engineer Research and Development Center, August 2021. http://dx.doi.org/10.21079/11681/41342.

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Aircraft Arresting Systems (AAS) for military applications utilize sacrificial panels made of Ultra-High Molecular Weight polyethylene (UHMWPE) that are embedded into the pavement beneath the AAS cable to protect the pavement from cable damage. Problems have been observed with the materials and practices used to seal the UHMWPE panel joints from water and debris. Data obtained from laboratory and field studies were used make improvements to current practice for sealing UHMWPE panel joints. The study evaluated four joint-sealant materials, eight alternative surface treatment and preparation techniques to promote adhesion to UHMWPE, and seven joint-edge geometries. Bond-strength testing of joint-sealant specimens was conducted in the laboratory, followed by field evaluation of construction techniques. Field performance of the joint systems was monitored for 24 months after installation. Additionally, a thermal response model was developed to refine the joint design dimensions. Results confirmed that the best material to use was self-leveling silicone joint sealant. It was recommended that a dovetail groove be cut into the edge of UHMW panels to provide positive mechanical interlock and to reduce adhesive failures of the sealant. It was also recommended that the panel-to-panel joint-sealant reservoir be widened to prevent sealant compression damage.

Hulata, Gideon, and Graham A. E. Gall. Breed Improvement of Tilapia: Selective Breeding for Cold Tolerance and for Growth Rate in Fresh and Saline Water. United States Department of Agriculture, November 2003. http://dx.doi.org/10.32747/2003.7586478.bard.

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The main objective of this project was to initiate a breeding program to produce cold-tolerant and salinity-tolerant synthetic breeds of tilapia, from a base population consisting of a four-species hybrid population created under an earlier BARD project. A secondary objective was to estimate genetic parameters for the traits growth rate under fresh- and salt-water and for cold tolerance. A third objective was to place quantitative trait loci that affect these traits of interest (e.g., growth rate in fresh-water, salt-water and cold tolerance) on the growing linkage map of primarily microsatellite loci. We have encountered fertility problems that were apparently the result of the complex genetic structure of this base population. The failure in producing the first generation of the breeding program has forced us to stop the intended breeding program. Thus, upon approval of BARD office, this objective was dropped and during the last year we have focused on the secondary objective of the original project during the third year of the project, but failed to perform the intended analysis to estimate genetic parameters for the traits of interest. We have succeeded, however, to strengthen the earlier identification of a QTL for cold tolerance by analyzing further segregating families. The results support the existence of a QTL for cold tolerance on linkage group 15, corresponding to UNH linkage group 23. The results also indicate a QTL for the same trait on linkage group 12, corresponding to UNH linkage group 4.