Weixing Yao

Weixing Yao
Nanjing University of Aeronautics & Astronautics · College of Aerospace Engineering

PhD

About

83
Publications
15,165
Reads
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1,537
Citations
Citations since 2017
2 Research Items
710 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Additional affiliations
September 1999 - present
Nanjing University of Aeronautics & Astronautics
Position
  • Yudao St. 29, Nanjing

Publications

Publications (83)
Article
Full-text available
In this paper, the S0-mode lamb wave phase velocity at low frequency range is chosen to characterize fatigue damages accumulated in composite laminates under cyclic loadings. A stiffness/velocity degradation model is proposed based on three distinctive damage mechanisms: fiber breaks, matrix cracks and delamination, all of which are always involved...
Article
Full-text available
The shear stress gradient effect is studied in this paper. First, based on the stress field intensity approach, which is very commonly used for the fatigue life prediction of notched specimens, a novel shear stress parameter is proposed. In this parameter, a weighted average stress is calculated near the fatigue critical point according to the rela...
Article
Full-text available
An energy-based continuum damage mechanics model was employed to investigate the effect of drilling-induced delamination on tensile strength of carbon fiber-reinforced polymer laminates and the residual strength was predicted. The decrease in tensile strength caused by delamination was investigated in detail by a finite element method (FEM) model....
Article
Full-text available
A concurrent subspace collaborative optimization (CSCO) technique is developed in this paper to deal with the layout, shape and size optimization of the hierarchical feature structures. The structural optimization is divided into three concurrent subspaces: the structural layout optimization, shape optimization and size optimization. And all these...
Article
Full-text available
This article provides an introduction to a decomposition-based method for the optimization of product families with predefined platforms. To improve the efficiency of the system coordinator, a new sensitivity-based coordination method (SCM) is proposed. The key idea in SCM is that the system level coordinates share variables by using sensitivity in...
Article
Full-text available
An energy-based continuum damage mechanics model was employed to investigate the effect of drilling-induced delam-ination on tensile strength of carbon fiber-reinforced polymer laminates and the residual strength was predicted. The decrease in tensile strength caused by delamination was investigated in detail by a finite element method (FEM) model....
Article
In this paper, based on the process of the fatigue crack initiation and the critical plane theory, a continuous stress parameter was proposed to quantify the driving force of the fatigue crack initiation for the fully reversed multiaxial fatigue loading. In this stress parameter, the shear stress amplitude and normal stress amplitude on the critica...
Article
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In this paper, the optimization considering the constraint of fatigue life was conducted on a bolted connection of a wing spar, after which a series of fatigue tests were carried out to verify the optimized result. The object of the optimization was to minimize the weight of the bolted connection. Meanwhile, a constraint of fatigue life was taken i...
Article
Full-text available
This paper discusses the problem of structural optimization of product families with predefined platforms. The main challenge lies in the increased design variables and constraints, and providing an optimal tradeoff for individual products performance in the family which are competitive with each other. The Concurrent Subspace Optimization for mult...
Article
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Based on Miner's law and probability theory, the probability density function of damage sum under the 2-stage step loading spectrum is proposed, by taking the logarithm normal distribution of the fatigue life into account. The method to determine the scatter of the accumulative fatigue damage is further proposed. A series of experiments under multi...
Article
In this paper, the influence on the multiaxial fatigue damage accumulation caused by loading path variation was studied. For 2024-T4 aluminium alloy, the damage evolution during the entire life was first observed. On the basis of the observation, the stage I of fatigue damage evolution was further divided into two sub-stages, and the dominant stres...
Article
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In the most of existing fatigue life prediction models, the maximum shear stress on a tubular specimen's outer surface is chosen as the shear stress parameter to predict fatigue lifetime for torsional loading. It has been experimentally found that the fatigue lifetime observed under fully reversed torsion is always higher than that under tension-co...
Article
Full-text available
In the initial period of the life in the composite laminates, the principal types of damage are diffused ones, such as matrix crack, diffused fiber breaking and local delamination. On account of these diffused damages, a synergistic damage mechanic model was proposed for the stiffness properties. The model included the microcosmic responses of the...
Article
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A stress mean square severity factor of joints in vibration excitation was given aiming at fatigue life estimation problem herein. This stress mean square severity factor considered comprehensively the concentration degree of root mean square stress, surface status and block coefficient at hole edge. Then a model was presented combining with the dy...
Article
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Taking the differences between the accumulative damage rules under multiaxial and uniaxial variable fatigue loadings into account, the multiaxial fatigue accumulative damage theories for metal materials were divided into the following four categories: (a) the directional linear models; (b) the directional nonlinear models; (c) the non-directional l...
Article
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Six accumulative damage models, which were common used or novel, were used to calculate the critical damages of the LY12CZ aluminum alloy under different kinds of 2-stage step loading spectra and the accuracy rate of each model was counted. According to the comparison result, for a certain kind of spectra, the prediction capabilities of the six mod...
Article
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Low-cycle fatigue tests at different frequencies and creep tests under different stress levels of Plexiglas Resist 45 were conducted. Correspondingly, the creep fracture time, S - N curves, cyclic creep, and hysteresis loop were obtained. These results showed that the fatigue life increases with frequency at low frequency domain. After analysis,...
Article
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The size effect on the strength of fiber reinforced plastic(FRP)composite is investigated.The two main factors,statistical size effect and free-edge effect,are responsible for the size effect in width. Statistical size effect originates from material inherent defects and it is described by the traditional Weibull weakest link theory.Free-edge effec...
Article
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For critical zone approach, the stress eigenvalues of a certain point, line or area in the vicinity of notch are used as the failure criteria. This paper presents a reasonable explanation for notch effect. Therefore, critical zone approach is considered as a fatigue life predicton method for notched specimens with a promising prospect in engineerin...
Article
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The actual load spectrum applied on structures is the key of the fatigue life monitoring. This paper presents a method of physical prototype centered assessment for fatigue life of structure based on on-line monitoring data. Firstly the load spectrums of fatigue hot regions are recorded by some sensors, then the load of the structure is inversely c...
Article
Full-text available
Mixed-mode energy-based delamination growth criteria of laminated composites are summarized after an extensive literature survey. Ten criteria of them are analyzed comprehensively based on Reeder's research using 22 groups of test data from 11 kinds of materials. Evaluation results show that, B-K criterion with three parameters and Power-Law criter...
Article
Full-text available
A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ aluminium alloy. The loading paths of 90° out-of-phase, 45° out-of-phase and 45° in-phase are utilized. The fatigue damage cumulative rules under two-level step loading of three loading paths are analyzed. By introducing a parameter α...
Article
Full-text available
To describe the centralized level of the stress root mean square (RMS) around a notch, this paper proposes a definition and calculation formula of the stress mean square concentration factor for notched specimens under dynamic excitation. A calculation formula for notch fatigue factor is presented based on the basic fatigue mechanism of structures...
Article
Full-text available
A layout optimum design formation for composite stiffened panel is proposed. This formation is composed of three steps. Firstly, a parametric finite element model is set up and the approximate model is used to construct the objective function of layout variables and size variables, and then to optimize the objective function by minimizing the mass...
Article
Several groups of fatigue damage parameters are discussed and then an improved multiaxial high-cycle fatigue criterion based on critical plane defined by the plane of maximum shear stress range is presented in this paper. A compromising solution to consider the mean normal stress acting on the critical plane is also proposed. The new fatigue criter...
Article
Full-text available
In order to take full advantage of the fatigue data from both the group test and the staircase test and thus get S-N curves with higher accuracy, a S-N curve regression approach is proposed based on the double weighted least square method. In this approach, effects of fatigue test method, fatigue data dispersion and test sample size on S-N curves a...
Article
This paper is to simulate the fatigue damage evolution in composite laminates and predict fatigue life of the laminates with different lay-up sequences on the basis of the fatigue characteristics of longitudinal, transverse and in-plane shear directions by finite element analysis (FEA) method. In FEA model, considering the scatter of the material’s...
Article
The mechanical properties of composite materials degrade progressively with the increasing of the number of cyclic loadings. Based on the stiffness degradation rule of composites, a phenomenological fatigue damage model is presented in this paper, which contains two material parameters. They are proportional to the fatigue life of materials and inv...
Article
Full-text available
To solve the fatigue life prediction problem of structures under bi-modal stress power spectral density in the frequency domain, this article presents a model of rainflow amplitude distribution of bi-modal stress power spectral density and provides a method to estimate its parameters. The rainflow amplitude distribution is assumed to be the combina...
Article
Full-text available
This article presents a model of rainflow amplitude distribution of a limited band white noise process and an estimation method of parameters in an attempt to provide fatigue life prediction for a structure under limited band white noise loading in the frequency domain. The rainflow amplitude was assumed to conform to bi-parameter Weibull distribut...
Article
Full-text available
The traditional stress severity factor (SSF) approach is almost unable to obtain the SSF value under complex geometry and loading boundaries. The maximum stress at the edge of a hole can be obtained easily by 3D FEM, but the process is time-consuming if the quality and filling status of the pin-loaded holes are included in the FE model; moreover, t...
Article
A frequency domain method for predicting the fatigue life of notched specimens under random vibration loading is presented. The effects of stress concentration and fatigue limit on life prediction are considered in this approach. Firstly, the stress response power spectral density is obtained by random vibration analysis and the influence of stress...
Article
Full-text available
The reasons of the static strength dispersion and the fatigue life dispersion of composite laminates are analyzed in this article. It is concluded that the inner original defects, which derived from the manufacturing process of composite laminates, are the common and major reason of causing the random distributions of the static strength and the fa...
Article
Full-text available
A sample approach was proposed herein, which was for fatigue life prediction. The approach can estimate the lifetime of structures under broad band random vibration loading in the frequency domain described by power spectral density. Firstly, random vibration loading in the frequency domain was converted to the repeated loading in the time domain....
Article
Very high cycle fatigue (VHCF) test of 82 aluminum alloy LC4CS specimens was done by piezo-electric fatigue testing machine and fatigue life data were obtained. The obtained fatigue life data showed that the fatigue life distribution of the alloy under VHCF has a characteristic of duplex peak, which is related to the locations of fatigue crack init...
Article
Full-text available
The interval reliability of some typical systems, such as scries system, parallel system, series-parallel system, parallel-series system, and r/n(G) system, etc. is studied based on the extension principle and the interval analysis. The interval reliability or interval failure probability of elements is analyzed. On the basis of the possibility deg...
Article
Full-text available
In order to reduce computation cost and improve convergence characteristic of collaborative optimization (CO), low degree-of-freedom collaborative optimization (LDFCO) is proposed. The system-level optimizes the problem target by changing the shared and auxiliary variables and being subjected to the consistency constraints. Each subsystem optimizes...
Article
Full-text available
Very high cycle fatigue (VHCF) test of 66 specimens of aluminum alloy LC4CS was done by piezo-electric fatigue testing machine, and the fatigue life data showed that the fatigue life distribution of the alloy under VHCF has a characteristic of duplex peak, which is related to the locations of fatigue crack initiation. For the specimens with shorter...
Article
Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the consta...
Article
Proportional and nonproportional tension–torsion fatigue tests were conducted on LY12CZ aluminum alloy. Two types of tubular specimens were used, one is smooth and the other is notched. The experimental data are analyzed. A new critical plane criterion including the strain and stress parameters is proposed. The capability of fatigue life prediction...
Article
A model for describing the fatigue damage and the creep-damage of the polymethyl methacrylate is proposed based on the damage mechanics, in which creep-damage and fatigue-damage evolution functions are deduced from Chaboche's and the increments of the creep-damage and the fatigue damage are additive. The creep and fatigue tests at different frequen...
Article
Full-text available
The failure of polymethyl methacrylate members of aircraft cabins is mainly caused by cyclic loading. A local stress approach for the fatigue life prediction of polymethyl methacrylate members is proposed based on the linear elastics characteristics of polymethyl methacrylate members under the cyclic loading in service. The local stress from the no...
Article
In this paper several multiaxial fatigue criteria are reviewed. The criteria are divided into three groups, according to the parameters used to describe the fatigue life or fatigue strength of materials. They are stress criteria, strain criteria and energy criteria. Their predictive capabilities are checked against the experimental data of six mate...
Article
Full-text available
S-N curves of all sorts of metals under general condition have been maturity. But the S-N curves considering the effect of corrosive environment are reported very rarely. This paper researches the S-N curves of aluminum alloy LY12-CZ under the constant amplitude loading after the corrosion of different equivalent calendar years. First, specimens ar...
Article
Full-text available
Tests of LC4 aluminum fatigue damage cumulative under fatigue(l) + corrosion + fatigue(2) mode have been carried out. The test results show that equal level loading tests under the mode have an analogy with low-high two level loading tests under general conditions. Preceding loading has a forging effect of low loading on the fatigue behavior of beh...
Article
A model was developed for predicting the stiffness degradation of fiber reinforced plastics (FRP), with ply configuration [0m/±θn]S, induced by matrix cracking under in-plane tension. The model assumes that the cracks in off-axis plies are uniformly distributed and a damage variable D is defined. Based on the theory of fracture mechanics, the elast...
Article
To predict the stress-strain response of a material subject to the random loading, an increment elastic-plastic finite element model is required. Repeated loads can be thought to be the alternative loading of the tension and compression, and the random loading can be considered to be the repeated loads that their amplitude are not equal. According...
Article
In this paper, the approaches of anti-fatigue design are briefly reviewed and are classified into three groups: nominal stress approach, local stress–strain approach and stress field intensity approach. Two types, each with two notches, are specially designed and a total of 30 specimens with 4 dimensions are tested under different constant–amplitud...
Article
A cumulative fatigue damage model is presented for predicting the fatigue life of fibre-reinforced plastics (FRP) subjected to variable amplitude fatigue loading. It is assumed that the cumulative fatigue damage caused by the cyclic loading is proportional to the strength loss of FRP, and that the damage state in laminates can be described phenomen...
Article
Full-text available
The state of the art in the residual strength of fiber reinforced plastics was reviewed. A new residual strength model based on the damage development in the plastics under fatigue loading was presented, which can macromechanically and phenomenologically describe the characteristics of fatigue damage. The model was verified by carbon fiber reinforc...
Article
A statistical analysis method for the evaluation of data from truncated fatigue life experiments and corresponding residual strength tests of polymer matrix composites is presented. This method is based on the conclusion that under a given fatigue stress S0 the conditional probability of specimen survival at a given fatigue life N0 is equal to the...
Article
Full-text available
In this paper, the tension-torsion specimens were used as researching subjects. The cyclic stress-strain relation under multiaxial proportional and nonproportional loading was studied according to the characteristic of the stress and strain on the multiaxial critical plane and the researching results of multiaxial critical plane principle. A multia...
Article
In this paper, the definition of fatigue crack initiation size and determining method were presented on the basis of the non-propagating cracks behaviour. The physical significance of fatigue crack initiation size was explained from the point of view of the fatigue damage. Fatigue crack initiation size is obtained by predicting a non-propagating cr...
Article
Full-text available
There are many approaches to predicting the fatigue strength of materials and structures , for example, the nominal stress approach and local stress strain approach. They are commonly used in the description of fatigue strength, but unfortunately the fatigue behavior is predicted poorly by these approaches. This paper presents a new fatigue design...
Article
This paper reviews the fatigue notch factor, Kf, and some expressions for it that are in current use. All the expressions for Kf can be classified into one of three types: the average stress model, the fracture mechanics model and the stress field intensity model analysis. These are compared on the basis of fatigue mechanism and experimental result...
Article
In this paper a new method for predicting notched strength of composites - the method of stress field intensity, in which the intensity of stress field near notch was taken as parameter to estimate the notched specimen, but not only the peak stress value at notch root, was presented. A general expression for predicting notched strength was given an...
Article
In this paper a new design approach for predicting fatigue life - the stress field intensity approach - is presented from the point of view of macromechanics on the basis of the mechanism of fatigue damage of metals. In this new approach the stress field intensity over the local region of damage, instead of the stress peak value as in the local str...
Article
A brief review of the recent and commonly used fracture models for predicting the notched strength of composite laminates is presented, and these models are then classified on the basis of macromechanics and a brief comparison between the models is given. On the basis of these analyses, a new fracture model for predicting the notched strength of co...
Article
The stress concentration factor of an orthotropic finite-width plate containing elliptical edge notches is analysed numerically using the finite element method and an expression is given to estimate this stress concentration factor. Some valuable results are provided for experimental and estimation of the notched strength of laminated plates.
Article
Full-text available
In this paper the main sources causing the scatter of experimental results of material parameters are discussed. They can be divided into two parts: one is the experimental errors which are introduced because of the inaccuracy of experimental equipment the experimental techniques, etc., and other is due to the irregularity and inhomogeneity of the...

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