Fracture and Structural Integrity最新文献_第8页

On the applicability of Miner’s rule for multiaxial fatigue life calculations under non-proportional load histories 非比例载荷历史下Miner规则在多轴疲劳寿命计算中的适用性

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.14

M. Meggiolaro, J. Castro, Samuel Elias Ferreira, Hao Wu

{"title":"On the applicability of Miner’s rule for multiaxial fatigue life calculations under non-proportional load histories","authors":"M. Meggiolaro, J. Castro, Samuel Elias Ferreira, Hao Wu","doi":"10.3221/IGF-ESIS.41.14","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.14","url":null,"abstract":"Fatigue design routines and computer codes must use some damage accumulation rule to deal with variable amplitude loadings (VAL), usually Palmgren-Miner (or Miner’s) linear rule for lack of a clearly better option. Nevertheless, fatigue lives are intrinsically sensitive to the order of VAL events, which may e.g. induce residual stresses and thus change the critical point stress state, much affecting its subsequent residual life. On the other hand, in general, non-linear damage accumulation rules are not robust, resulting in better predictions than Miner’s rule only for some specific load orders, requiring a case-by-case analysis. Therefore, Miner’s linear damage rule still is the usual choice in practical fatigue calculations and assessments, giving reasonable predictions at least when properly combined with approaches that sequentially consider plasticity-induced effects, following the critical point stress/strain history in a cycle-by-cycle basis. In this work, Miner’s rule is evaluated for non-proportional tension-torsion loadings on annealed tubular 316L stainless steel specimens. Normal-shear strain histories following either cross, diamond, circular or square paths are applied, and their fatigue lives are measured. Then, more complex VAL paths consisting of combinations of these individual path shapes are applied in other specimens, whose associated fatigue lives are predicted based on Miner’s rule.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"220 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122469000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Regularities of fracture pattern formation in alumina ceramics subjected to dynamic indentation 动态压痕作用下氧化铝陶瓷断裂模式形成规律

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.65

E. Tolmacheva, M. Davydova, V. Chudinov, S. Uvarov, O. Naimark, D. Zaytsev, P. Panfilov

引用次数: 1

Study of strain localizations in a polycrystalline medium in presence of a quasi-static crack 准静态裂纹存在下多晶介质中应变局部化的研究

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.37

L. Patriarca, P. Luccarelli, S. Foletti

{"title":"Study of strain localizations in a polycrystalline medium in presence of a quasi-static crack","authors":"L. Patriarca, P. Luccarelli, S. Foletti","doi":"10.3221/IGF-ESIS.41.37","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.37","url":null,"abstract":"Numerical techniques have been widely applied in many recent works to investigate micro-scale behavior of materials. This work focuses on the analysis of strain localizations in a Nickel-based alloy, Haynes 230. Numerical models and experiments concern the study of the strain field generated around the crack tip inside a polycrystalline medium when the crack is quasi-static (not propagating). Experimentally, the tests were conducted in load control; one face of the specimens was monitored by high-resolution Digital Image Correlation (DIC) technique to evaluate the strain field ahead of the crack tip. The simulations were conducted adopting an open source finite element code, Warp3D, which implements a state of art Crystal Plasticity (CP) model. The models of the polycrystalline matrix were created considering the data obtained inspecting the specimen surface by the Electron Back-Scatter Diffraction (EBSD) technique, which allowed defining grains size and orientations. Experimental and numerical results were then compared in terms of strain localizations to evaluate the prediction capabilities of the models. The comparison focused on strain field extension and active grains.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114615668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of spectral cross-correlation on multiaxial fatigue damage: simulations using the critical plane approach 光谱互关对多轴疲劳损伤的影响:用临界平面法模拟

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.06

A. Carpinteri, A. Spagnoli, S. Vantadori

{"title":"Effect of spectral cross-correlation on multiaxial fatigue damage: simulations using the critical plane approach","authors":"A. Carpinteri, A. Spagnoli, S. Vantadori","doi":"10.3221/IGF-ESIS.41.06","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.06","url":null,"abstract":"The present paper aims to discuss a frequency-domain multiaxial fatigue criterion based on the critical plane approach, suitable for fatigue life estimations in the presence of proportional and non-proportional random loading. The criterion consists of the following three steps: definition of the critical plane, Power Spectral Density (PSD) evaluation of an equivalent normal stress, and estimation of fatigue damage. Such a frequency-domain criterion has recently been validated by using experimental data available in the literature, related to combined proportional and non-proportional bending and torsion random loading. The comparison with such experimental data has been quite satisfactory. In order to further validate the above criterion, numerical simulations are herein performed by employing a wide group of combined bending and torsion signals. Each of such signals is described by an ergodic, stationary and Gaussian stochastic process, with zero mean value. The spectrum of each signal is assumed to be represented by a PSD function with rectangular shape. Different values of correlation degree, variance and spectral content are examined.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126736648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Parametric study of the deformation of transversely isotropic discs under diametral compression 横向各向同性圆盘在直径压缩下变形的参数化研究

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.51

C. Markides, S. Kourkoulis

{"title":"Parametric study of the deformation of transversely isotropic discs under diametral compression","authors":"C. Markides, S. Kourkoulis","doi":"10.3221/IGF-ESIS.41.51","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.51","url":null,"abstract":"The displacement field in a circular disc made of a transversely isotropic material is explored in a parametric manner. The disc is assumed to be loaded by a parabolic distribution of compressive radial stresses along two finite arcs of its periphery in the absence of any tangential (frictional) stresses. Advantage is here taken of a recently introduced closed-form analytic solution for the displacement field developed in an orthotropic disc under diametral compression which was achieved adopting the complex potentials technique for rectilinear anisotropic materials as it was formulated in the pioneering work of S.G. Lekhnitskii. The analytic nature of this solution permits thorough, indepth exploration of the influence of some crucial parameters on the qualitative and quantitative characteristics of the deformation of transversely isotropic circular discs compressed between the jaws of the devise suggested by the International Society for Rock Mechanics for the standardized implementation of the Brazilian-disc test. The parameters considered include the anisotropy ratio (i.e., the ratio of the two elastic moduli characterizing the disc material), the angle between the loading axis and the planes of transverse isotropy and the length of the loaded arcs. Strongly non-linear relationships between these parameters and the components of the displacement field are revealed.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128876753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Review of the influence of non-singular higher order terms on the stress field of thin welded lap joints and small inclined cracks in plates 非奇异高阶项对薄焊接搭接接头和板内小斜裂纹应力场影响的综述

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.35

F. Berto, M. Ayatollahi, S. Vantadori, A. Carpinteri

{"title":"Review of the influence of non-singular higher order terms on the stress field of thin welded lap joints and small inclined cracks in plates","authors":"F. Berto, M. Ayatollahi, S. Vantadori, A. Carpinteri","doi":"10.3221/IGF-ESIS.41.35","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.35","url":null,"abstract":"In stress analysis of cracked plates, alongside the stress intensity factor which quantifies the singular stress component perpendicular to the crack plane, the role played in crack growth by the constant term parallel to the crack plane, called the T-stress, has been widely investigated by many researchers. There are, however, cases of practical interest where the influence on the stress field of the higher order terms in the series expansion for the crack tip stress field, is not negligible. The main aim of the present investigation is to present and apply a set of equations able to describe more accurately the stress components for those cases where the mode I and mode II stress intensity factors used in combination with the T-stress are unable to characterise with sufficient precision the complete stress field ahead the crack tip. The starting point is represented by the Williams’ solution (Williams, 1957) where stresses as expressed in terms of a power series. An example is investigated of a thin-thickness welded lap joint characterized by various joint width to thickness ratios, in the range of d/t ranging from 0.5 to 5. The present paper indicates that the local stresses as well as the strain energy averaged over a control volume which embraces the slip tip, can be evaluated with satisfactory precision only by taking into account a further four terms besides KI, KII and T-stress.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132788324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

An original method of direct calculation for the identification of the last hinge and the definition of the deformative state at collapse 提出了一种确定最后铰的直接计算方法和确定铰在崩溃时的变形状态

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.46

Roberto Maria De Salvo

{"title":"An original method of direct calculation for the identification of the last hinge and the definition of the deformative state at collapse","authors":"Roberto Maria De Salvo","doi":"10.3221/IGF-ESIS.41.46","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.46","url":null,"abstract":"The subject matter of these notes refers to the Ultimate Strength Design of 2-D steel framed structures and in particular to the analysis of the deformation state at collapse. The idea is based on the consideration that, if the structure at its collapse condition is subjected to an articulated movement, similar and concordant to the crisis motion, this will not change the stress state of the system. This motion is known once a single parameter is fixed, namely the displacement of a point or the rotation of a beam. When the collapse mechanism of the structure is already determined through any instrument of the Limit Analysis, a subsequent (k+1) plastic hinge can be arbitrarily fixed and assumed as the last developed one. It is therefore possible to solve the modified scheme through the rotation method and make a comparison in the verses between the known plastic moments and the rotations at the corresponding hinges. If the comparison is successful, in the sense that the checked verses are concordant, the selected hinge is actually the one formed as the last. On the contrary, the rotations resulting from an imprinted motion in the verse of collapse movement are algebraically added. If, for each hinge, the product between the plastic moment and the correspondent algebraic sum is made, this product has to be surely positive, due to the verses concordance. This can be translated in k+1 inequalities, with each one furnishing a lower limit for the parameter from which the articulated motion depends. Among these, the highest value is that one which makes all the inequalities to be simultaneously verified. The substitution of this value into the expressions for rotations permits to arrive to the simultaneous identifying of the last hinge and of the complete picture of deformations.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132389603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On DIC measurements of DeltaKeff to verify if it is the FCG driving force 对DeltaKeff的DIC测量来验证它是否是FCG的驱动力

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.31

Julián Andrés Ortiz González, J. Castro, G. Gonzáles, M. Meggiolaro, J. Freire

引用次数: 3

Crack tip strain evolution and crack closure during overload of a growing fatigue crack 扩展疲劳裂纹过载时裂纹尖端应变演化与裂纹闭合

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.20

De-Qiang Wang, Mingliang Zhu, F. Xuan

{"title":"Crack tip strain evolution and crack closure during overload of a growing fatigue crack","authors":"De-Qiang Wang, Mingliang Zhu, F. Xuan","doi":"10.3221/IGF-ESIS.41.20","DOIUrl":"https://doi.org/10.3221/IGF-ESIS.41.20","url":null,"abstract":"It is generally accepted that fatigue crack growth is retarded after an overload, which has been explained either by plasticity-induced crack closure or near-tip residual stress. However, any interpretation of overload effect is insufficient if strain evolution in front of crack tip is not properly considered. The current understanding of overload-induced retardation lacks the clarification of the relationship between crack closure at crack wake and strain evolution at crack tip. In this work, a material with low work hardening coefficient was used to study the effect of overload on crack tip strain evolution and crack closure by in-situ SEM observation and digital image correlation technique. Crack opening displacement (COD) and crack tip strain were measured before and after the overload. It was observed that the evolution of crack tip strain follows the crack opening behaviour behind the crack tip, indicating a smaller influence of overload on micro-mechanical behaviour of fatigue crack growth. After the overload, plastic strain accumulation was responsible for crack growth. The strain at a certain distance to crack tip was mapped, and it was found that the crack tip plastic zone size correlated well with crack growth rate during post-overload fatigue crack propagation.","PeriodicalId":300868,"journal":{"name":"Fracture and Structural Integrity","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116466502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

The effect of creep damage formulation on crack tip fields, creep stress intensity factor and crack growth assessments 蠕变损伤公式对裂纹尖端场、蠕变应力强度因子和裂纹扩展评价的影响

Fracture and Structural Integrity Pub Date : 2017-06-28 DOI: 10.3221/IGF-ESIS.41.38

V. Shlyannikov, A. Tumanov

引用次数: 4