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In this study, we reviewed the definitions of indentation strain and stress proposed from earlier studies and then calculated indentation strain–stress curves according to 20 combinations of five indentation strain definitions and four indentation stress definitions. The finite element method was applied to predict the load–displacement curves and the force–displacement for spherical nanoindentation and tensile test, respectively. Thus, the load–displacement data were used to determine indentation strain–stress curves, which were compared with the stress–strain curve, obtained from the tensile test simulation. Comparing with the tensile stress–strain curve, three combinations of σX − ɛK, σO − ɛA, and σH − ɛM reveal better fitting curves than the other combinations, where the subscripts of X, K, O, A, H, M are denoted as Xu and Chen (J Mater Res 25:2297-2307, 2010), Kalidindi and Pathak (Acta Mater 56:3523-3532, 2008), Oliver and Pharr (J Mater Res 7:1564-1583, 1992, J Mater Res 19:3-20, 2004), Ahn and Kwon (J Mater Res 16:3170-3178, 2001), Hill et al. (P R Soc Lond 423:301-330, 1989), and Milman et al. (Acta Metal Mater 41:2523-2532, 1993), respectively. The limitation of the indentation strain is at 0.06, 0.03, and 0.01 for combinations of σX − ɛK, σO − ɛA, and σH − ɛM. The stress constraint factor (called the ratio of mean contact pressure to tensile stress) for combinations of σX − ɛK, σO − ɛA, and σH − ɛM is 3.4, 3.4, and 2.6 to obtain the optimized fitting indentation stress–strain curves with the parameter n of the power law of 0.306, 0.248 and 0.173, which reveal the deviation of 43.0%, 15.9%, and 19.2%, respectively, in comparison with that of the tensile flow curve. Considering the best fitting curve by the combination of σO − ɛA, together with the stress constraint factor $$\psi$$ of 3.4, the fitting parameters of n and K are 0.248 and 588.56 corresponding to the deviation of 15.9% and 7.7% in terms of these parameters in the tensile flow curve.

At moderate stresses, shear cells are the preferred method of powder flow measurement. However, several industrial processes operate at low stresses, where the determination of unconfined yield strength by the shear cell technique may be inconsistent, or found not to correlate with observed behaviour. Alternatively, ball indentation can be used, which directly measures hardness; related to unconfined yield strength by the constraint factor. However, it is not known how constraint factor is influenced by particle properties. Here, ball indentation and shear cell methods are applied for glass beads of various size distributions, and the influence of particle size distribution on the constraint factor is explored. The constraint factor is shown to be independent of the pre-consolidation stress, though reduces as the d10, d50 or d90 are increased. Unconfined yield strength inferred from indentation measurements suggest that extrapolation of shear cell data to low stresses overestimates the unconfined yield strength

In industrial processing and manufacturing, characterizing the flowability of particulate solids is of particular importance both for reliable powder flow and for a consistent production rate. Shear testing is the most widely used method for powders subjected to moderate or high stresses, and under quasi-static conditions. However, this method is not suitable for measuring the powder flow properties occurring in dynamic systems, such as powder mixers and screw conveyors. In this study, the rheological behaviour of powders at high shear rates has been evaluated by the ball indentation method. The technique, which simply consists of dropping a ball onto a cylindrical bed of previously consolidated powder, directly measures the material hardness, which is related to the unconfined yield stress by the constraint factor. The impact of the ball on the bed is recorded with a high-speed camera to determine velocity and penetration depth. The hardness against the strain rate is considered for four different materials. Because of their difference in particle size, and by using a range of drop heights and a range of indenter densities, the intermediate regime of flow has been fully analyzed. Although hardness is constant in the quasi-static condition, it results to be strain rate dependent in the intermediate regime of flow. Finally, a predictive correlation that allows the operator to choose the best operating conditions for achieving the desired flow regime is proposed, and the unconfined yield strength of the materials is inferred.

International audience; Using cracked pipes design standards and finite element analysis, the limit load analysis for pipes containing surface cracks was determined. The study was performed on five pipes of different diameters with a constant crack length and depth. The crack geometry is a semi-elliptical surface crack. The cracked pipes are subjected to internal pressures which are obtained from formulas of cracked pipes design standards. Due to the ductile behavior of polyethylene pipes, the failure occurs when the critical stress reaches a value equal to the ultimate tensile strength multiplied by a constraint factor. In this work, the constraint factor was calculated and its evolution with the pipe diameter was analyzed. Three different definitions of a constraint factor based on global or local approaches were also compared, so that a new failure criterion can be obtained. The new failure criterion makes the prediction of the pipe residual life possible which, in turn, facilitates a systematic approach to maintenance and replacement of pipes.

The crack propagation mechanism of thick plates is difficult to describe accurately, and thus, it is difficult to predict the lifetimes of thick plate structural cracks in extreme construction environments. In this paper, a theoretical model of the time-integrated crack propagation that accounts for the thickness effect is established. The constraint factor is introduced to characterize the thickness effect of crack propagation, and the constraint factor formula was obtained by fitting the experimental results. The results of the fatigue crack growth tests and the crack propagation theoretical predictions for Q345D specimens showed the time-integrated crack propagation model predicts the crack propagation more accurately in the initial stage and during the stable expansion stage of crack propagation. These results have guiding significance for the fatigue life prediction of equipment with thick plate structural features.

International audience; Solid circulation in chemical looping combustion (CLC) is very important and affects the mass and heat balance and autothermal operation of a CLC system. A key task in developing CLC technology is to control the solid circulation. In this work, the solid circulation characteristic of a 1.5 MWth CLC cold flow model is reported. The solid circulation between the fuel reactor and the simplified air reactor riser is controlled by the overflow method. Three kinds of quartz sands are selected as fluidized particles, and their median particle diameters are 392, 249, and 122 μm, respectively. A reasonable pressure profile is obtained in the 1.5 MWth CLC cold flow model. The effects of operational parameters, including the fuel reactor gas velocity, loop seal gas velocity, simplified riser gas velocity, particle size, and static bed height, on the solid circulation and hydrodynamic characteristics are measured and analyzed. The maximum solid circulation rate can approach 130 kg/(m2·s), and this value satisfies the requirements of mass and heat balance in the CLC system. The static bed height in the fuel reactor should be higher than the overflow port to prevent it from becoming a constraint factor on the solid circulation rate. An overflow model is developed to predict the solid circulation rate, and the relative errors between the predicted result and the experimental data are within 25%.

The urban road network system is the main carrier of urban traffic. The constraint factor that urban road network has on traffic leads to major urban traffic problems. In this paper, a questionnaire survey and the Delphi method are determined to determine the case cities with a population of 1-2 million at home and abroad. Literature research and comparative, analytical, and inductive research methods are used to compare, analyse, and evaluate the advantages and disadvantages of the road network structure of the case cities, to summarize the development law of the urban road network, and to propose a sustainable development structure model for each development stage of urban road network: the mode made of ring freeway + trunk street (the embryonic stage), the mode made of ring freeway + expressway + trunk street (the incubation stage), the mode made of outer ring freeway + outer ring expressway and radial expressway + trunk street (the mature stage). The innovative point of this paper is to put forward a sustainable development pattern for the road network structure of cities with a population of 1-2 million in China.

Ball indentation is a technique capable of assessing powder flowability down to very low consolidation stresses (≤1 kPa). With this method, powder flowability is determined by measuring the hardness of a powder bed, which allows the unconfined yield strength to be inferred via the constraint factor. The latter is well established for continuum materials, whereas for particulate systems its dependency on stress level and powder properties is not well defined. This work investigates these factors by simulating the ball indentation method using DEM. The constraint factor is shown to be independent of pre-consolidation stress. Constraint factor generally increases with interface energy for relatively cohesion-less powders, though not for cohesive powders. An increase in plastic yield stress leads to a decrease in the constraint factor. Increasing the coefficient of interparticle static friction reduces the constraint factor, while increasing the coefficient of inter-particle rolling friction significantly increases the constraint factor.

The quality of transportation service it’s a main factor to increase the level of economic and social in Sarawak. By increasing the system may buzz-up all sector and may contribute the benefit to the community. This research will be conducting in four selected locations consist of Sibu, Miri, Bintulu and Kuching. The reason to choose these four locations it’s because of the role that each location plays in contributing to the economic sector in Sarawak state itself. Methodology to be used to conduct this research its quantitative method. Where, 300 set of questionnaire to be distributing to the stated locations to get a perception on the concept of sustainable transportation among respondents. Questionnaire distributing to those who has knowledge towards sustainable transportation and it’s limited to those who have experience in construction sector only. The objectives of this research it’s to investigate the construction player’s perception towards sustainability transportation in Kuching, Miri, Bintulu and Sibu; and to identify the barriers factor to implementing this concept. Expecting distribution from this research it’s to create awareness by implementing this concept it’s beneficial to the routine activities as well as can generate and increase the Sarawak’s economic sector.

The purpose of this study is to examine the constraint factors of the e-learning learning system. This type of research is literature review research with a descriptive approach. The results of the study obtained regarding the constraint factors in the e-learning learning system include; quota and network/internet connection, equipment used, learning facilities, understanding of course management in e-learning, limited time for managing e-learning, lack of commitment from schools and teachers regarding the development of e-learning learning, funds needed for e-learning implementation still limited, school leadership policies in allocating funds for the development of learning media, long loading times for information or films, mentoring time by parents, teachers' technological abilities, costs, psychologically face-to-face directly affect the level of understanding

The study investigates fatigue growth and shape evolution of a corner crack in a pin-loaded hole by means of three-dimensional FE analyses. The constraint factor/plasticity-induced crack closure strategy was tuned to reproduce experimentally measured crack front shapes. The study quantitatively determines the LEFM acceptability regions using elastic–plastic simulations. It also assesses the sensitivity of crack propagation and shape evolution to the stress distribution along the front, to the relationship between J-integral and stress intensity factor, and to changing propagation rates along different directions. The proposed approach produces very accurate results in terms of crack propagation rate and shape evolution.

Gravity geologic method is one of the important to derive seafloor topography by using altimetry-gravity, and its committed step is gridding of regional gravity anomaly. Hence, we proposed a topography constraint factor weight optimization (TCFWO) method based on ordinary kriging method. This method fully considers the influence of topography factors on the construction of regional gravity grid besides horizontal distance. The results of regional gravity anomaly models constructed in the Markus-Wake seamount area show that the TCFWO method is better than ordinary kriging method. Then, the above two regional gravity models were applied to invert the seafloor topography. The accuracy of derived topographic models was evaluated by using the shipborne depth data and existing seafloor topography models, including ETOPO1 and V19.1 model. The experimental results show that the accuracy of ST_TCFWO (seafloor topography model inverted by TCFWO method) is better than ST_KR (seafloor topography model inverted by kriging method) and ETOPO1 model. Compared with the ST_KR, the accuracy of the ST_TCFWO has improved about 26%. In addition, the accuracy of seafloor topography is affected by the variation of depth, the distribution of control points and the type of terrain. In different depth layers, the ST_TCFWO has better advantages than ST_KR. In the sparse shipborne measurements area, the accuracy of ST_TCFWO is better than that of V19.1, ETOPO1 and ST_KR. Moreover, compared to other models, ST_TCFWO performs better in flat submarine plain or rugged seamount area.

The modified constitutive model for predicting the tensile ductility of Al-Si casting alloys was proposed as an extended form in terms of the effective void area fraction that takes into account the geometric configuration and size distribution of pre-existing micro-voids and eutectic Si particles. And, its prediction accuracy was verified through comparison between the theoretical predictions by original Ghosh’s constitutive model and the experimental results of T4-treated A356 alloys. The theoretical prediction by modified constitutive model shows high accuracy which has only a deviation below 10% for the tensile strain of an individual test specimen, compared with a deviation of approximately 40% from the original Ghosh model. The plastic constraint factor and incoherency parameter of the modified constitutive model can effectively describe not only the geometric array and size distribution of micro-voids and eutectic Si-particles but also the additional variation of load-carrying area by damage evolution of Si-particles. The theoretical prediction based upon the largest size of pre-existing micro-void can predict more exactly the overall tensile strain of a material, comparing with a nominal value of average size.

Conferencia invitada. Fracture Mechanics is currently an essential subject for understanding failure mechanisms of engineering materials and components. Accurate and rapid evaluation of singular and non-singular terms of stress, strain and displacement fields in the neighbouring of the tip of a fatigue crack is the foundation of multi-parameter Fracture Mechanics [1]. These terms are normally described by means of the Stress Intensity Factor (SIF) and the T stresses and are very useful to assess the level of safety [2] and the stability of cracks and crack-like defects in mechanical components prone to linear elastic failure, both under constant [2–7] and variable amplitude loading [8–11]. In general, evaluation of such terms cannot be performed only by finite element method [12–14]. This is due to the difficulty in accurately accounting for load level and exact geometry and orientation of defects [3,15]. Consequently, hybrid methods that incorporate experimental information [16,17] into an analytical and/or a numerical approach tend to be more trustworthy. Among these, full-field experimental techniques such as electronic speckle pattern interferometry [18–20], digital image correlation [21–27], thermo-elastic stress analysis [28–30], X-ray diffraction [31–33] and photo-elasticity [34–38] are often preferred. Estimation of Fracture Mechanics parameters requires accurate positioning of the crack tip. Moreover, local deformations as well as rigid body movements need to be taken into consideration. This research will summarise a general methodology including the above-described aspects for Fracture Mechanics analyses. Departamento de Ingeniería Civil, de Materiales y Fabricación Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

Najpoznatija metoda za određivanje udarnog rada loma te procjenu ponašanja materijala u uvjetima udarnog opterećenja je Charpyjeva metoda. U ovom znanstveno-istraživačkom radu uspoređeni su rezultati ispitivanja dobiveni pomoću instrumentirane Charpy metode s rezultatima dobivenim statičkim vlačnim ispitivanjem u svrhu procjene prihvatljivosti rezultata ispitivanja instrumentiranom Charpy metodom kod zavarenih spojeva. Tu se prije svega misli na karakteristične sile (sila pri granici razvlačenja i maksimalna sila) te naprezanju pri granici razvlačenja i naprezanju pri maksimalnoj sili. U svrhu ispitivanja uzorci za Charpyjevu i statičku vlačnu metodu izrađeni su iz osnovnog materijala, metala zavara i zone utjecaja topline. Iz dijagrama sila-vrijeme i sila-pomak, dobivenih instrumentiranom Charpy metodom, određene su vrijednosti karakterističnih sila i dinamičkih čvrstoća pri istim silama. Norma za instrumentiranu Charpy metodu daje samo okvirne naputke na koji način odrediti vrijednosti karakterističnih sila, stoga se je prišlo pronalaženju nove metode njihove procjene koja je korištena u ovom radu. U svrhu proračuna dinamičke čvrstoće pri granici razvlačenja i dinamičke lomne žilavosti koristile su se poznate metode, dok je za proračun vrijednosti dinamičke vlačne čvrstoće korištena nova metoda procjene. Rezultati ispitivanja pokazali su dobru korelaciju između rezultata dobivenih instrumentiranom Charpyjevom metodom i rezultata dobivenih statičkim vlačnim pokusom što otvara mogućnost za daljnja istraživanja na tom području. The best known method for determining absorbed energy and evaluation of material behaviour under the impact conditions is Charpy impact test. In this research results of the mechanical properties obtained from instrumented Charpy method were compared with results obtained from static tensile test. The purpose is to evaluate the acceptability of the results obtained from the instrumented Charpy method of welded joints. Yield force, maximum force, dynamic yield strength and dynamic tensile strength are in the main focus of this work. Samples for instrumented Charpy method and for static tensile test are machined from the base material, weld metal and head affected zone. Yield and maximum forces, as well as the dynamic strengths at the stated forces were estimated from the force-time diagram and force-displacement diagram obtained from instrumented Charpy method. Standard for instrumented Charpy method gives only the general guide how to estimate values of the stated forces, hence the new method for its estimation is introduced. To estimate the dynamic yield strength and dynamic fracture toughness, common methods were used. New method was introduced to estimate dynamic tensile strength. Test results show good correlation between results given by instrumented Charpy method and results given by static tensile test which opens the possibility for further researches.

Max-sum is a version of Belief Propagation, used for solving DCOPs. In tree-structured problems, Max-sum converges to the optimal solution in linear time. Unfortunately, when the constraint graph representing the problem includes multiple cycles (as in many standard DCOP benchmarks), Max-sum does not converge and explores low quality solutions. Recent attempts to address this limitation proposed versions of Max-sum that guarantee convergence, while ignoring some of the problem's constraints. Damping is a method that is often used for increasing the chances that Belief Propagation will converge. That being said, it has not been suggested for inclusion in the algorithms that propose Max-sum for solving DCOPs. In this paper we advance the research on incomplete-inference DCOP algorithms by: 1) investigating the effect of damping on Max-sum. We prove that, while damping slows down the propagation of information among agents, on tree-structured graphs, Max-sum with damping is guaranteed to converge to the optimal solution in weakly polynomial time; and 2) proposing a novel method for adjusting the level of asymmetry in the factor graph, in order to achieve a balance between exploitation and exploration, when using Max-sum for solving DCOPs. By converting a standard factor graph to an equivalent split constraint factor graph (SCFG), in which each function-node is split into two function-nodes, we can control the level of asymmetry for each constraint. Our empirical results demonstrate a drastic improvement in the performance of Max-sum when using damping (referred to herein as Damped Max-sum, DMS). However, in contrast to the common assumption that Max-sum performs best when converging, we demonstrate that non converging versions perform efficient exploration, and produce high quality results, when implemented within an anytime framework. On most standard benchmarks, the best results were achieved using versions with a high damping factor, which outperformed existing incomplete DCOP algorithms. In addition, our results imply that by applying DMS to SCFGs with a minor level of asymmetry, we can find high quality solutions within a small number of iterations, even without using an anytime framework. We prove that for a factor graph with a single constraint, if this constraint is split symmetrically, Max-sum applied to the resulting cycle is guaranteed to converge to the optimal solution. We further demonstrate that for an asymmetric split, convergence is not guaranteed.

The effective stress intensity factor range Δ K eff is commonly considered to govern the fatigue crack growth and may be estimated through the crack opening stress S op and the constraint factor α . In the literature closed-form expressions have been developed for estimating both variables in a center-cracked plate with elastic-perfectly plastic behavior subjected to remote uniform stresses. However, such expressions are frequently adopted regardless of geometry, material and loading and, moreover, α is often given a fixed value. The final objective is to assess the suitability of existing constraint and closure models for performing accurate crack-growth predictions in configurations that do not meet the original hypotheses. The region-II growth of a hole-edge crack is predicted in the 42CrMo4 steel by integrating crack growth laws calibrated with data from standard compact tension (CT) specimens. The results show overall better predictions by using the same constraint model for estimating α in both geometries, rather than by treating it as a fitting parameter in CT specimens. Unexpectedly, the predictions obtained at different stress ratios were, in general, more accurate by integrating a non-closure law based on Δ K and independent of S op and α .

As a clean energy source, LNG has been widely used. LNG ships need to enter and leave the port area through the channel. With the development of the port, the ship traffic will gradually increase. As a manual excavation of narrow and long channel, its passing capacity will become a constraint factor for LNG receiving stations and port development. In this paper, the system simulation method is used to study the impact of LNG ship entry and exit on the passage capacity of the channel, which can provide basis and reference for the planning, site selection and channel construction of the LNG receiving station.

Features of renovation of built-up areas are considered. The main difficulties in carrying out the renovation process are identified. The concept of the constraint factor of the building is defined. Methods. A method for analyzing and assessing constraints for selecting optimal organizational and technical solutions for the renovation of territories is proposed. Results. An analysis algorithm is proposed, based on the consideration of the constraint factor as an array of actions of individual “objects of influence” on the corresponding “subjects of influence”. Conclusion. Сonducting such an analysis will provide the most effective and optimal organizational and technological solutions reflected in the relevant sections of the renovation project in high-rise construction (development of a construction master plan, preparation of calendar and network work schedules). The implemented rational version of the design solution ensured the reduction of the prime cost and the reduction of the terms of the preparatory works for the renovation of housing construction projects taking into account seismic uncertainty. Renovation is one of the varieties of this reconstruction of high rise construction.

Higher order J-A2 solution has been developed to improve the HRR singular solution under ideal plane strain conditions in power-law hardening solids with the the second A2 being considered to take into account of the in-plane constraint effect, and the J-Tz singular solution has been obtained for three-dimensional (3D) cracked body by introducing the out-of-plane stress constraint factor Tz. Here a higher order J-Tz-AT solution is developed on the basis of the J-Tz and J-A2 solutions and validated against comprehensive 3D finite element (FE) analyses for specimens with through-thickness, surface, embedded and corner cracks. It is shown that better agreements are obtained between the higher order J-Tz-AT solution and 3D FE results in all simulated conditions than previously available two- or three-parameter solutions. For specimens of high in-plane constraint, such as the single-edge cracked tension specimen, compact specimen and single-edge-notched bending specimen under three-point bending, the J-Tz leading singular solution itself shows sufficient accuracy. This universal characterization of crack border stress fields confirms that the developed J-Tz-AT solution combines the advantages of the J-Tz and J-A2 solutions, which can service as a solid foundation of elastic-plastic fracture mechanics.

The inability of cohesive powders to flow consistently and reliably is a major cause of process downtime and reduced efficiency across a wide range of powder processing industries. Most methods to assess powder flowability fail at low consolidation pressures (

International audience; The application of the concept of the representative strain is often used in the stress-strain curve determination from indentation test because it can significantly simplify the analysis of the indentation response. A new methodology for determining the representative strain for Vickers indentation is presented in this article. Following a procedure based on finite element simulations of indentation of elastoplastic materials, two representative strains are defined: the representative strain characteristic of the mean pressure and the representative strain characteristic of the Martens hardness or the indentation loading curvature. The results obtained from this methodology show that there is no universal value of representative strain independent of the mechanical parameters of materials indented by Vickers indentation. It is also shown that the representative strain, obtained by Vickers indentation is much lower when it is obtained from the relationship between the applied force and the penetration depth, F-h, rather than from the relationship between the applied force and the contact radius, F-a. The values of the calculated representative strains show that simultaneous measurement of relationships F-a and F-h make it possible to characterize the hardening law with two unknown parameters by Vickers indentation.

Video object segmentation has been widely used in many fields. A conditional random fields (CRF) model is proposed to achieve accurate multi-class segmentation of video objects in the complex environment. By using CRF, the color, texture, motion characteristics and neighborhood relations of objects are modeled to construct the corresponding energy functions in both the temporal and spatial domains. The model is trained with annotated samples by using LogitBoost classifier. The energy function is amended by adding a constraint factor which is used to indicate the interaction between two adjacent images in the video sequence. Experimental results show that the proposed algorithm can achieve high performance for multi-class objects segmentation in videos under complex environment. It can also get good recognition results when dealing with multi-viewed objects or serious sheltered objects.

The extension of the available stress-based predictive models from uniaxial to multiaxial feature is uncertain due to the difficulty to justify the model transferability to the cases which involves complex deformation and fracture mechanisms. This paper presents a new approach to predict the creep rupture life of Grade 92 steel under multiaxial stress state as the case of notched bar samples using Kachanov's Continuum Damage Mechanics (CDM) model. Combining the CDM model with the concept of Hayhurst's representative stress and accounting two extreme conditions; fully dislocation-controlled and diffusion-controlled creep mechanisms provide the bounds for short- and long-term rupture data of notched bar up to 10,000 h. Although the CDM is scientifically relevant and fundamental in their approach, it is generally complex and contains too many variables. Therefore, it needs proper measurements or numerically intensive to make the model acceptable for industrial applications. Alternatively, the recent developed strain-based exponential-type predictive model which links globally uniform failure strain with a multiaxial constraint factor was employed with the intention to reduce the large number of CDM parameters. The approach is relatively simple yet reliable to be used for high temperature creep rupture assessment.

Fatigue damage is one of the most common failure modes of large-scale engineering equipment, especially the full-face tunnel boring machine with characteristics of a thick plate structure bearing strong impact load. It is difficult to predict the location and propagation life of crack of cutterhead under strong impact load. Unseasonal maintenance of equipment caused by inaccurate prediction of life cycle of cutterhead seriously affects the construction efficiency of the equipment and the life safety of the operators. Determining the crack location of tunnel boring machine cutterhead structure under strong impact load and predicting the crack propagation life are difficult scientific problems. To solve them, first, the location of the stress concentration of the cutterhead is determined by using finite element analysis method of statics. Second, prediction model for crack propagation life of tunnel boring machine cutterhead characteristic substructure based on time integration is built. And the test of crack growth of cutterhead characteristic substructure is performed. The feasibility and accuracy of the prediction model are verified by contrasting crack prediction models and the results of the test. Finally, the life prediction of tunnel boring machine cutterhead of water diversion project in Northwest Liaoning Province is carried out by using crack propagation model based on time integration. Results show that the maximum error of theoretical prediction and experimental results of crack propagation is 16%. So the feasibility of crack propagation model based on time integration in predicting the crack growth of cutterhead is verified. It is predicted that the tunnel boring machine cutterhead panel can work normally for 5.9 km under the condition of ultimate load. Building the crack propagation model considering the influence of plate thickness and strong impact load has important research value for improving the working efficiency of engineering equipment, prolonging service time, and improving the working safety.

To accurately predict damage behavior in engineering applications, it is important to investigate the three-dimensional (3D) stress state near a real crack border. Introducing the out-of-plane stress constraint factor T z , Guo and his colleagues derived out the 3D asymptotic fields near the tensile crack border in power law plastic ( Guo, 1993a, 1993b, 1995 ) and creeping solids ( Xiang et al., 2011 ). However, these theoretical solutions are presented in curves and too complicated for application. Here we formulize the 3D theoretical solutions into a set of empirical explicit formulae in the whole range of out-of-plane stress constraint from T z = 0 at plane stress state to T z = 0.5 at plane strain state. At the two limits of T z = 0 and 0.5, the empirical formulae degrade into the two dimensional (2D) HRR ( Hutchinson, 1968; Rice and Rosengren, 1968 ) or RR ( Riedel and Rice, 1980 ) solutions with high accuracy. Detailed finite element analyses are performed for cracked plates with finite thickness under power law plastic and creeping conditions to verify the formulation of the asymptotic crack border stress fields. It is shown that the in-plane stress components and stress triaxiality on the ligament ahead of the crack border can be efficiently predicted by the explicit formulae. We also investigate the dominance of the formulation of stress components in the whole forward sector to give a more convenient description for wide applications. Based on the formulation, we discuss the influence of both in-plane and out-of-plane constraints. Three-parameter descriptions, such as the J – T z – Q T description for plastic solids proposed by Guo (2000) and the C ( t )– T z – Q ∗ description for creeping solids proposed by Xiang et al. (2011) are evaluated based on comparison of the empirical formulae and 3D finite element results. The three-parameter descriptions are shown to be necessary and efficient under large scale yielding or extensive creeping conditions in the whole forward sector of cracked plates with finite thickness.

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Some researchers have argued that a majority of Japanese have a strong desire to continue living in their current residence. This study hypothesized that some of these individuals, however, may well have a strong desire to change residence when they consider that actual requirements for receiving nursing care in the future. This paper, then, investigates preferences for and constraints on moving to a final residence, given the necessity of nursing care. The data are based on a questionnaire survey conducted among inhabitants of detached houses in suburban Hitachi City which is one of the typical suburban cities in Japan. A McNemar's test and correspondence analysis showed that less than 25% of the inhabitants were relatively certain that they would continue living in their current house in the future, whereas most were likely to change their residence whether they wanted to do or not. Furthermore, the inhabitants faced the necessity of compromising in the selection of their future residence (whether or not this involved a change of residence) due to a sense of being undeserving or out of consideration for their children.

A new approach for determining initiation fracture toughness J i has been developed based on acoustic emission (AE) and has been tested and validated on a SA333 Gr.6 steel. The J i values thus determined are in close agreement with those obtained from both ASTM A-15 prescription and stress zone height (SZH) measurements using a constraint factor M = 4. This confirms the use of higher values of M (>2) in the blunting line equation J = Mσ y Δ a where M is the slope of the blunting line, σ y is the effective yield strength, and Δ a is the crack extension.

As China's economy continues to develop, it has formed a long-term conflict between the people's cultural requirements and cultural productivity. Development of folk music culture of our country needs to reform and innovation to another level. There are still many problems in Folk Music Teaching in our country, such as backward teaching methods , improper specialty setting, they have became an important constraint factor for Folk Music teaching Development. Therefore, how to promote the deep reform of folk music teaching development from all aspects, is a problem that we and the whole China need serious consideration. This article will elaborate existing problems and corresponding measures from various aspects of the system of National Folk Teaching.

A complete three-parameter K–T–Tz description of the mixed-mode I/II three-dimensional (3D) crack-tip stress fields has been proposed, in which the stress intensity factor K, T-stress and out-of-plane constraint factor Tz around mix-mode I/II crack front in compact-tension-shear specimens are all the functions of the Poisson ratio v, thickness ratio zB and load angle φ. By fitting the numerical results with the least squares method, empirical formulae have been obtained to accurately describe the 3D distributions of the three parameters for the convenience of engineering applications, which can be used to characterize the 3D crack-tip stress fields completely and establish the three-parameter dominated stress fields.

Creep fracture of solids at high temperature is vital to applications of many advanced materials, but most of the previous works are performed within the frame of two-dimensional theory. By using the out-of-plane stress constraint factor T z , here we derive out three-dimensional asymptotic fields near the border of mode-I through-thickness cracks in power law creeping solids. It is found that the asymptotic fields near the crack border are dominated by both T z and C ( t ) integral. Detailed finite element analyses are carefully performed for single-edge cracked specimens and centre-cracked tension specimens to investigate the dominance of the asymptotic solution for the crack border fields. It is shown that the C ( t ) − T z description based on the obtained three-dimensional asymptotic solution can provide efficient prediction for the tensile stress ahead of the crack front under small scale creep condition. Under extensive creep conditions, a third parameter Q ∗ should be introduced to take into account of the loss in the in-plane constraint caused by in-plane geometries and loading configuration at extensive creeping, and a three-parameter C ( t ) − T z − Q ∗ description is proposed and proven to be efficient to predict the tensile stress on the ligament ahead of the crack for both specimens. Therefore, the two-parameter C ( t ) − T z and three-parameter C ( t ) − T z − Q ∗ descriptions can provide advanced theoretical basis for small and extensive creeping fracture assessments, respectively.

The fast spread of Chinese gall wasp (Dryocosmus kuriphilus) represents a new constraint factor for chestnut stands and orchards in Italy. So far, the favourable effect of hypovirulence in Cryphonectria parasitica-Castanea sativa patho-system allowed the development of chestnut cultivation. This situation could be modified by the progressive weakening of the trees caused by intensive attacks of the new parasite. During recent surveys worrying blight damage recurrences were observed in different Italian chestnut areas (in Piemonte, Trentino and Toscana regions) which were highly infested by the Chinese wasp. While biological control treatments against the parasite are carried out, it is necessary to set up integrated protocols for the management of chestnut orchards to allow the survival of trees and their productivity.

Based on data analysis proved that during 20152060, the number of Muslim population increased rapidly by increasing 70%, which is included converts in South Korea. The developments of Islam in South Korea characterized by the growing mosque of Seoul, Itaewon Mosque Islamic Center. The main constraint factor for Korean converts is there is still no prayer guide in Hangeul feature. Constraints experienced by converts, most important is prayer. The Korean Muallaf Center is an application that helps converts to include wudu, prayers, and easy-to-understand religious worship. The purpose of this research is to help converts to understand the guidelines of Islam with Hangeul, so that they can practice it. The methodology of this research is with literature study, application design, implementation, and evaluation of application usage. The results of this study are the Korean Muallaf Center Applications that have been used by Muallaf Korea.

The concept of the T-stress as a local constraint factor has been extended to U-notch tip stress distribution as the effective T-stress. The effective T-stress has been estimated as the average value of the T-stress in the region corresponding to the effective (characteristic) distance ahead of the notch tip. The T-stress is evaluated by finite element method using the experimental load for crack initiation and computing the difference between principal stresses along ligament. A large range of critical effective T-stress values is investigated for different specimen configurations and notch aspect ratios. Crack stabilisation and crack bifurcation for fracture emanating from notches according to the critical effective T-stress is discussed. A model involving the influence of the critical effective T-stress on void growth for ductile failure in the vicinity of the notch tip has been proposed.

The ball indentation (BI) testing is used to evaluate the tensile properties of materials namely yield strength, strength coefficient, ultimate tensile strength, and strain hardening exponent. The properties evaluated depend on a number of BI test parameters. These parameters include the material constants like yield slope (YS), constraint factor (CF), yield offset parameter (YOP). Number of loading/unloading cycles, preload, indenter size and depth of penetration of indenter also affects the properties. In present investigation the effect of these parameters on the stress-strain curve of normalized and tempered Grade 92 steel is evaluated. Grade 92 is a candidate material for power plant application over austenitic stainless steel and derives its strength from M23C6, MX precipitates and high dislocation density. CF, YS and YOP changed the strength properties considerably. Indenter size effect resulted in higher strength for smaller indenter. It is suggested to use larger indenter diameter and higher number of loading cycles for GRADE 92 steel to get best results using BI technique.

Nitrogen (N) is one of macronutrients which is dynamic in the soil and becomes constraint factor for rice crops. The addition of nitrogen fertilizers and its absorption in paddy field causes the dynamics of nitrogen, thus declines of N absorption efficiency. The aim of this research is to know influence Azolla, biochar and different varieties application on N-NH4 +, N-NO3 -, and total soil N in paddy field. This research was conducted in a screen house located in Jumantono Laboratory, Faculty of Agriculture, Universitas Sebelas Maret (UNS) with altitude 170 m asl from April to June 2016. Treatment factors that were examined consisted of azolla (0 and 10 tons/ha), biochar (0 and 2 tons/ha), and rice varieties (Cisadane, Memberamo, Ciherang, IR64). The results of this research showed that there was no interaction between azolla, biochar and varieties. Nevertheless, azolla treatment with dose of 10 tons/ha increased soil NH4 + content (41 days after planting, DAP) by 13.4% but tend to decrease at 70 and 90 DAP. Biochar treatment with dose of 2 ton/ha increases NO3 - soil content (70 DAP) by 1.7% but decreases total N soil by 5.8% (41 DAP) and 4.7% (90 DAP). Different rice varieties generated different soil NH4 + content (41 DAP) and rice root volume. Cisadane variety can increase soil NH4 + content (41 DAP) by 52.08% and root volume by 51.80% (90 DAP) compared with Ciherang variety. Organic rice field management with azolla and biochar affects the availability of N in the soil and increase N absorption efficiency through its role in increasing rice root volume.

Based on the behavior of a three-void cluster embedded within a representative volume element, this study utilizes three-dimensional finite element analyses to examine the sensitivity of void growth and coalescence to strain hardening, multiaxial stress state and inter-void spacing. The strain-induced growth of voids within the cluster is accelerated when the voids are closely spaced in a low strain-hardening material subject to high levels of stress triaxiality. Far-field deformation causes strain to concentrate within the inter-void ligament, and the resulting behavior induces a load–loss response of the inter-void region. Based on the load–loss criterion for the onset of void coalescence, the results show that coalescence is accelerated by increasing stress triaxiality and decreasing strain hardening and inter-void spacing. A straightforward analysis is then presented that relates void coalescence to (a) the strain-hardening exponent and (b) the dependence of the plastic constraint factor within the inter-void ligament on strain, the latter being sensitive to far-field stress triaxiality and void geometry.