Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences最新文献_第9页

High– and low–cycle fatigue crack initiation using polycrystal plasticity 利用多晶塑性引发高、低周疲劳裂纹

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-07-08 DOI: 10.1098/rspa.2003.1258

A. Manonukul, F. Dunne

{"title":"High– and low–cycle fatigue crack initiation using polycrystal plasticity","authors":"A. Manonukul, F. Dunne","doi":"10.1098/rspa.2003.1258","DOIUrl":"https://doi.org/10.1098/rspa.2003.1258","url":null,"abstract":"A polycrystal plasticity finite–element model has been developed for nickel–base alloy C263. That is, a representative region of the material, containing about 60 grains, has been modelled using crystal plasticity, taking account of grain morphology and crystallographic orientation. With just a single material property (in addition to standard elastic properties), namely, the critical resolved shear stress, the model is shown to be capable of predicting correctly a wide range of cyclic plasticity behaviour in face–centred cubic nickel alloy C263. A fatigue crack initiation criterion is proposed, based simply on a critical accumulated slip. When this critical slip is achieved within the microstructure, crack initiation is taken to have occurred. The model predicts the development of persistent slip bands within individual grains with a width of ca. 10 μm. The model also predicts that crack initiation can occur preferentially at grain triple points under both low– (LCF) and high–cycle fatigue (HCF). For the case of HCF, this also corresponds to a free surface. The polycrystal plasticity model combined with the fatigue crack initiation criterion are shown to predict correctly the standard Basquin and Goodman correlations in HCF, and the Coffin–Manson correlation in LCF. The model predictions are based on just two material properties: the critical resolved shear stress and the critical accumulated slip. Just one experimental test is required to determine these properties, for a given temperature, which have been obtained for nickel alloy C263. Predictions of life for nickel alloy C263 are then made over a broad range of loading conditions covering both LCF and HCF. Good agreement with experiments is achieved, despite the simplicity of the proposed ‘two–parameter’ model. A simple three–dimensional form of the model has provided an estimate of the fatigue limit for HCF crack initiation in C263.","PeriodicalId":20722,"journal":{"name":"Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91346452","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: 236

Holographic velocimetry with object conjugate reconstruction (OCR): simultaneous velocity mapping in fluid and solid mechanics 具有物体共轭重建(OCR)的全息测速:流体和固体力学中的同步速度映射

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-07-08 DOI: 10.1098/rspa.2003.1265

D. Barnhart, N. Halliwell, J. Coupland

引用次数: 6

Flow and deformation in poroelastic media with moderate load and weak inertia 中等载荷弱惯性孔隙弹性介质的流动与变形

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-07-08 DOI: 10.1098/rspa.2003.1250

C. Lee

{"title":"Flow and deformation in poroelastic media with moderate load and weak inertia","authors":"C. Lee","doi":"10.1098/rspa.2003.1250","DOIUrl":"https://doi.org/10.1098/rspa.2003.1250","url":null,"abstract":"The governing equations for the deformation and the fluid flow in a poroelastic medium are derived under (i) a moderately small ratio of external load to elastic stiffness which is of O(ε), where ε = l/l′ is the ratio of the microscale to the macroscale lengths, and (ii) a moderately small pore- (or grain-) size-based Reynolds number which is of O(ε1/2), by employing the theory of homogenization. The macroscale governing equations are nonlinear in general and several canonical boundary–value problems are defined in a unit cell with a periodic structure on the microscale. However, to determine the effects of inertia and deformation on the macroscale seepage flow, only a few cell problems need to be solved. The correction to Darcy's law in deformable media is shown to be cubic in the seepage velocity as in the case of a rigid medium but with modified permeability and inertial effect due to deformation. It is also shown that Darcy's law is stated with permeability which is dependent on the state of elastic strain of the medium throughout the consolidation process. While the changes due to fluid inertia and medium deformation are small but as important as the inertial effects in rigid media, the porosity and permeability changes for a medium isotropic on the macroscale are shown to be linearly proportional to the volume strain of the medium, and also modify the inertial effect in Darcy's law accordingly, as compared with the case for a rigid medium.","PeriodicalId":20722,"journal":{"name":"Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81863564","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: 7

An exactly solvable microgeometry in torsion: assemblage of multicoated cylinders 扭转中的精确可解微几何:多涂层圆柱体的组合

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-07-08 DOI: 10.1098/rspa.2003.1268

Tungyang Chen

{"title":"An exactly solvable microgeometry in torsion: assemblage of multicoated cylinders","authors":"Tungyang Chen","doi":"10.1098/rspa.2003.1268","DOIUrl":"https://doi.org/10.1098/rspa.2003.1268","url":null,"abstract":"An exact expression for the torsional rigidity of a cylindrical bar with arbitrary transverse cross–section filled with an assemblage of multicoated inclusions is derived. The exact formula depends on the constituent shear rigidities, the area fractions and the size distribution of the multicoated inclusions, but is independent of the assembly microstructure. The analysis is based on a successive construction of neutral multicoated inclusions under Saint–Venant's torsion. We show how to design permissible multicoated inclusions, with phase–shear rigidities and area fractions appropriately balanced, so that after its introduction into a homogeneous host bar the warping field in the host bar will not be disturbed. What makes the neutral inclusion under torsion particularly intriguing is that both the constraint conditions and the torsional rigidity are independent of the location of the neutral inclusion. One can thereby add many neutral inclusions to fill up the cross–section without further derivations. Without solving any field equations, we prove that the torsional rigidity of a given cross–section filled with an assemblage of multicoated inclusion can be exactly determined in a simple, explicit form.","PeriodicalId":20722,"journal":{"name":"Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83425171","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: 10

A study of the characteristics of white noise using the empirical mode decomposition method 利用经验模态分解方法研究白噪声的特性

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1221

Zhaohua Wu, N. Huang

引用次数: 1639

Reconstructing the cross–sectional area of an axially vibrating non–uniform rod from one of its mode shapes 用非均匀轴向振动杆的某一振型重构其横截面积

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1214

Y. Ram, I. Elishakoff

引用次数: 12

Green's function for a two–dimensional exponentially graded elastic medium 二维指数梯度弹性介质的格林函数

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1220

Youn-Sha Chan, L. Gray, T. Kaplan, G. Paulino

引用次数: 88

On the Lennard–Jones EAM potential 关于Lennard-Jones EAM电位

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1190

S. G. Srinivasan, M. Baskes

引用次数: 14

Wetting and bonding characteristics of selected liquid metals with a high–power diode–laser–treated alumina bioceramic 选定液态金属与高功率二极管激光处理的氧化铝生物陶瓷的润湿和键合特性

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1228

J. Lawrence

{"title":"Wetting and bonding characteristics of selected liquid metals with a high–power diode–laser–treated alumina bioceramic","authors":"J. Lawrence","doi":"10.1098/rspa.2003.1228","DOIUrl":"https://doi.org/10.1098/rspa.2003.1228","url":null,"abstract":"Changes in the wettability characteristics of an alumina bioceramic occasioned by high–power diode–laser (HPDL) surface treatment were apparent from the observed reduction in the contact angle. Such changes were due to the HPDL bringing about reductions in the surface roughness, increases in the surface O2 content and increases in the polar component of the surface energy. Additionally, HPDL treatment of the alumina–bioceramic surface was found to effect an improvement in the bonding characteristics by increasing the work of adhesion. An electronic approach was used to elucidate the bonding characteristics of the alumina bioceramic before and after HPDL treatment. It is postulated that HPDL–induced changes to the alumina bioceramic produced a surface with a reduced band–gap energy, which consequently increased the work of adhesion by increasing the electron transfer at the metal–oxide interface and thus the metal–oxide interactions. Furthermore, it is suggested that the increase in the work of adhesion of the alumina bioceramic after HPDL treatment was due to a correlation existing between the wettability and ionicity of the alumina bioceramic, for it is believed that the HPDL–treated surface is less ionic in nature than the untreated surface and therefore exhibits better wettability characteristics.","PeriodicalId":20722,"journal":{"name":"Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87785940","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: 7

Lamb quasi–modes in curved plates 弯曲板中的Lamb准模态

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences Pub Date : 2004-06-08 DOI: 10.1098/rspa.2003.1254

D. Gridin, R. Craster

引用次数: 11