Analysis Of Damage Accumulation Research Articles

A data-driven underground gas storage production system string failure prediction model for time-varying reliability analysis

In underground gas storage (UGS) systems, the production tubing string system undergoes complex thermo-mechanical loading conditions, leading to fatigue damage accumulation and potential failure risks. To accurately assess the fatigue reliability and mitigate risks, it is crucial to develop a data-driven physics-informed uncertainty modeling approach that captures the coupled thermo-mechanical effects and accounts for various uncertainties. This study proposes a data-driven physics-informed modeling method based on thermo-mechanical coupling for fatigue reliability assessment and risk mitigation in critical UGS systems. A quantitative analysis method is introduced, which relies on small-scale multi-stage loading experiments and combines the stochastic degradation process with time-series reliability theory. To analyze the fatigue life of joints under complex loading conditions, a modified S-N curve model is developed. This model takes into account the influences of the dimension coefficient, stress concentration factors, surface finish coefficients, and thermal load. It considers the uncertainties associated with different temperature loads and surface finish on fatigue life. By integrating physics-informed modeling, uncertainty quantification, and fatigue damage accumulation analysis, this approach provides a comprehensive framework for fatigue reliability assessment and risk mitigation in critical UGS systems. It enables informed decision-making for safe and reliable operations, as well as optimized maintenance strategies, ultimately enhancing the overall system performance and mitigating potential failures.

Multi-Stage Hybrid Loading Fatigue Life Prediction Study

Abstract Fatigue is a damage accumulation process in which material properties are continuously deteriorated and degraded under cyclic loading. Damage accumulation analysis plays a key role in preventing the occurrence of fatigue failure, and the damage evolution mechanism is an important parameter of interest for fatigue behavior. The fatigue cumulative damage life prediction model is established by focusing on the damage evolution mechanism, and an improved Manson–Harford cumulative damage nonlinear model is developed to calculate fatigue damage life by considering the effect of load ratio of multi-stage loading on fatigue life. A fatigue life prediction method considering high-low cycles and multi-stage mixed loads is proposed. The fatigue life prediction accuracy of the model is verified by fatigue tests on structural samples. The accuracy of the fatigue life prediction error is the highest among similar models under the same test, the model proposed in this paper.

The Fe addition as an effective treatment for improving the radiation resistance of fcc NixFe1-x single-crystal alloys

In this work, five different compositions of fcc Ni and NixFe1-x single crystal alloys namely Ni, Ni0.88Fe0.12, Ni0.77Fe0.23, Ni0.62Fe0.38, Ni0.38Fe0.62 were irradiated by 1.5 MeV 58Ni ions at room temperature in a wide fluence range (4 × 1013 to 4 × 1015 ions/cm2). The role of Fe addition on the radiation resistance of the NixFe1-x single crystals was studied by transmission electron microscopy (TEM), ion channeling technique (RBS/C) and nanoindentation techniques. The Multi-Step Damage Accumulation analysis revealed the cross-sections for damage formation significantly decreases for Ni0.38Fe0.62 and Ni0.62Fe0.38 as compared to that in pure Ni single crystal, which is consistent with RBS/C and TEM results. The results of nanoindentation show that Ni0.62Fe0.38 alloy possesses the highest hardness (2.96 GPa) among the other compositions in a pristine state. To interpret this result, hybrid Monte Carlo/ Molecular dynamics simulations were used to check the presence of the ordered crystal phase structure for NixFe1-x binary alloys. The simulation results have shown that depending on the iron content, we deal with different amounts of FeNi3 (L12) phase. This result revealed that in Ni0.62Fe0.38 alloy, nanoprecipitate FeNi3 (L12) phase (around 20%) is formed inside the disordered matrix, which could be one of the main reasons for the high hardness of this alloy before irradiation.Additionally, we have found adding iron reduced the number and size of the defects (as a result of ion irradiation) in NixFe1-x because the Fe element is more stable than Ni, which results from the electron configuration of both elements in the excited state. Therefore, the more iron in the material, the fewer defects are created.

Analysis of Speckle-Structure Images of Material Surface During Cyclic Loading Damage Accumulation Using Neural Networks

To estimate the degree of damage to a material subjected to cyclic loading at stresses above the endurance limit, a technique has been proposed for analyzing speckle images of the material surface at the stage of diffuse accumulation of fatigue damage using neural networks. The microdeformation density of the specimen surface was quantitatively estimated by non-contact speckle interferometry. In the process of loading, an image of speckle structure in the initial state and before fatigue crack nucleation with a certain periodicity was recorded. Two classes of images are distinguished for damage accumulation analysis. The first one is the images corresponding to damage accumulation up to 10% of durability, the second one – more than 90%. The configuration of the network after its training makes it possible to determine to which class the speckle-structure images of the material belong during the accumulation of fatigue damage.

Modeling of Polymer Composite Materials Chaotically Reinforced with Spherical and Cylindrical Inclusions.

The technical and economic efficiency of new PCMs depends on the ability to predict their performance. The problem of predicting the properties of PCMs can be solved by computer simulation by the finite element method. In this work, an experimental determination of the physical and mechanical properties of PTFE PCMs depending on the concentration of fibrous and dispersed filler was carried out. A finite element model in ANSYS APDL was built to simulate the strength and load-bearing capacity of the material with the analysis of damage accumulation. Verification of the developed computer model to predict the mechanical properties of composite materials was performed by comparing the results obtained during field and model experiments. It was found that the finite element model predicts the strength of chaotically reinforced spherical inclusions of composite materials. This is due to the smoothness of the filler surfaces and the lack of filler dissection in the model. Instead, the prediction of the strength of a finite element model of chaotically reinforced cylindrical inclusions of composite materials requires additional analysis. The matrix and the fibrous filler obviously have stress concentrators and are both subject to the difficulties of creating a reliable structural model.

Operating regime investigational study of steel-reinforced concrete superstructure flexible pin stops of the existing road bridge

In the article, the author published the full-scale experiment results on an existing steel-reinforced concrete road bridge, carried out to determine the actual parameters of the operation regime of the interconnection elements — flexible pin stops. This work was carried out as part of the author's dissertation research in the field of improving methods for testing the elements' endurance of the steel-reinforced concrete superstructures interconnection and is a development of the previously conducted comprehensive comparative analysis of existing models for testing endurance. The article gives a detailed description of the conditions for conducting and methods of a two-stage experiment, which includes short-term and long-term parts, as well as a detailed description used for processing experimental data for each of the stages. Based on the results of the experiment's short-term part, when compared with the results of finite element modeling of the operation of the stops, the possibility of using existing computational models to describe the actual model operation was confirmed. Also, within the framework of the short-term part, according to the conducted dynamic tests results with the moving load passage through the threshold, the presence of a significant dynamic component of the resulting forces in the interconnection stops was revealed. During the second long-term part of the experiment, a continuous recording of stresses in the interconnection elements from the passage of an unregulated traffic flow over the bridge was made. The article presents both direct survey data (tensograms) and the results of their further processing in terms of damage accumulation analysis; also, the accumulated damages values from actual traffic loads are compared with the expected values in the calculation according to some design standards. Intermediate conclusions based on the experiment results are formed and directions for future work within the scope of this study are indicated.

Кинетические уравнения ползучести и повреждаемости для описания материалов с немонотонной зависимостью деформации при разрушении от напряжения

Introduction. Reducing the level of damage accumulation during pressure treatment of materials at elevated temperatures in creep and close to superplasticity modes in the manufacture of parts can significantly increase its service life in the cold state. Finding temperature and power conditions leading to a reduction in damage of material during the production process and operation is an important task. The purposes of the work: 1) to show the possibility of using the Sosnin-Gorev creep and damage model for alloys with a non-monotonic dependence of strain at fracture on diagrams with creep curves; 2) to carry out comparative analysis of damage accumulation under conditions of uniaxial tension at constant stress and at constant strain rates for alloy with such a dependence. Research methods. Used scalar damage parameter is equated to the normalized deformation, i.e. to the ratio of the current strain to the fracture strain. To find the coefficients of relations creep and damage, the similarity of the creep curves in the normalized values “normalized strain – normalized time”, i.e. the presence of single normalized curve of damage accumulation is checked. The least squares method is used to approximate the experimental data. Numerical integration methods are used for comparative analysis of deformation modes. Results and discussion. Determination of the parameters of the creep and damage equations by the method of a single normalized curve is carried out on the example of experimental data for steel 12Kh18N10T (12Cr18Ni10Ti) at 850 °C, which has a minimum of fracture strain in diagrams with creep curves. Analysis of the static and kinematic modes of deformation for studied material showed that damage accumulation in both cases is practically the same for stresses close to the stress at which this minimum is reached. If the stresses are lower, then the lower level of damage accumulation will be in the kinematic mode; if the stresses above the minimum value, then the static mode will lead to a lower level of damage accumulation. Application. The obtained results can be useful when choosing rational modes of forming structural elements from alloys with a non-monotonic dependence of the fracture strain on stress, as well as in evaluating it for long-term strength during operation.

Damage accumulation analysis of cfrp cross-ply laminates under different tensile loading rates

This paper investigates the loading rate effect on both mechanical properties and damage accumulation process of [0°2/90°4]S carbon fiber-polymer laminates under tensile loading. In-situ edge observations, Acoustic Emission and Digital Image Correlation techniques were utilized simultaneously to monitor the state of damage in real time. Results showed that the axial modulus and strength were less sensitive to loading rates than failure strain, which increased with the decrease of the loading rate. In the viewpoint of damage accumulation process, high density and uniform distribution of transverse matrix cracks, and H-shape crack patterns, incorporating inter-laminar cracks, were more likely to occur at low loading rates while variable crack spacing occurred at higher rates. When loading rates were lower than a certain level, maximum transverse matrix crack density decreased slightly due to the restriction of relatively widely generated inter-laminar cracks. Furthermore, the cumulative acoustic emission energy of low-frequency signals was linearly correlated to transverse matrix crack density, providing a promising way to quantify crack accumulation in real time. Finally, spatial consistence was observed between transverse matrix cracks at edges and stress concentrations at the exterior 0° ply, and the peaks of axial strain at local concentration regions locate either near the newest cracks or at the place with minimum crack spacing.

Improved fatigue damage accumulation analysis based on material memory property

PurposeFor the difference of the change law of material memory performance and the influence of damage state on memory performance, this paper aims to establish a general model of fatigue damage accumulation based on dynamic residual S–N curve and material memory characteristics.Design/methodology/approachThis paper introduces the material memory characteristics, combined with the residual S–N curve method, and uses the exponential decay function of the load cycle to construct the material memory performance function. While considering the damage state, the loading order can be fully considered. The parameter d in the function not only represents the variation of the material's memory property, but also considers the influence of the damage state.FindingsAccording to the test data of welding joints of common materials, alloy materials and other materials, the validity and feasibility of the fatigue cumulative damage model constructed were verified. The numerical results show that under the grading load, the fatigue cumulative damage model can be used to predict the fatigue life of welded structures and has high prediction accuracy and more approximate to the actual experiment results. It can be directly applied to the fatigue life prediction and design of actual engineering welded structures.Originality/valueThe model not only considers the effect of damage state and loading order on damage accumulation, but also contains only one material parameter, which is easy to obtain. The prediction accuracy and engineering practicability of fatigue were significantly improved.

Random fatigue damage accumulation analysis of composite thin-wall structures based on residual stiffness method

The damage accumulation and life prediction for C/SiC composite panels subjected to random vibration loading was studied by using the residual stiffness model in combination with critical failure stiffness ratios in the different stress levels. According to the results of stiffness degradation and material S-N curves for constant-amplitude fatigue loadings, a new residual stiffness model was established and extended to adapt random stress states by using an equivalent damage ratio algorithm in time domain. The stiffness degradation and material S-N curves were obtained by using constant amplitude fatigue experiments. Random vibration tests with limited-bandwidth excitation were conducted to verify the prediction model. Good agreement is observed compared with the results of 2D plain-woven C/SiC composite panel subjected to random vibration loadings.

Numerical model for the stress field ahead of a crack in elastoplastic regime

Damage-tolerant designs admit the pre-existence of defects and small cracks, which lead to stress redistribution in structural components. The accurate knowledge of the stress field in parts under these conditions is important for damage accumulation analysis and residual life prediction. In this work, a numerical model via finite elements is proposed to determine the stress field ahead of crack tips in a plate under cyclic loading and elastoplastic regime. The analyzed center-cracked plate simulates a M(T) specimen made of 6005-T6 extruded aluminum alloy. From the triple symmetry condition, one eighth of the plate was discretized with tetrahedral solid finite elements of quadratic order. The refinement of the mesh was concentrated around the crack tip region. The cyclic stress-strain curve of the material was experimentally obtained by strain-controlled fatigue tests. With this curve, elastic and plastic parameters have been determined, considering elastoplastic material with isotropic hardening governed by Swift’s law. Such a model differs from most usual stress analyses in cracked components, in which the possibility of hardening is not considered. Cyclic loading with ratios R = 0 and R = -1 has been applied from an initial crack of 11 mm in length. The crack growth was imposed by means of a simplified node release scheme. The results showed no significant variation in terms of the equivalent stress, but considerable differences in the equivalent plastic strain. Therefore, the compressive phase in the specimen under R = -1 contributes to increase the equivalent plastic strain, which means that the level of yielding becomes higher even when the specimen is compressed.

Розповсюдження фронту руйнування при повзучості в пластинах з надрізами

Development of the time determination methods between the completion stage hidden destruction of the constructive element and point of its complete destruction is relevant for creep research and operation life evaluation of the various machine elements. These elements loosened by various snips and work in difficult temperature and power conditions. Based on the proposed method of numerical analysis of de-struction front proliferation the results of the damage accumulation analysis due to the creep and the propagation time determination of front destruction in plates are presented. These plates are weakened by sharp and circular symmetrical snips. Sharp or circular snips concentrators are quite common in machine elements and have a constructive or technological importance. It was found that the complete destruction time of the plates in a non-uniform stress state due to the stress concentration around the snips greatly exceeds the latent stage duration of destruction. The practical value of the proposed method lies in the fact that there is the ability to assess resource of the different machine parts, in which the period of hidden damage accumulation is ended and macro destructions are emerged.

A nonlinear fatigue damage accumulation model considering strength degradation and its applications to fatigue reliability analysis

Fatigue is a damage accumulation process in which the material property deteriorates and degenerates continuously under cyclic loading. The analysis of damage accumulation plays a key role in preventing the occurrence of fatigue failures, and the damage evolution mechanism is one of the important focuses of fatigue behavior. In this paper, a residual strength degradation model according to the stress–strength interference (SSI) model is introduced firstly; then a modified nonlinear fatigue damage accumulation model based on the Manson–Halford theory is proposed. Combining the proposed nonlinear damage accumulation model with the residual strength degradation model, a new method is developed for fatigue life prediction under constant and variable amplitude loading, which considers not only the effects of load interactions, but also the phenomenon of strength degradation of materials induced by loading history, and it can be used to predict the reliability and fatigue life of mechanical components. Moreover, the material parameter for the residual strength degradation can be obtained directly from S–N curve without running extra experiments. Finally, experimental data are used to compare with the predicted value in order to demonstrate the proposed residual strength degradation model. In addition, two sets of experimental data are also used to verify the proposed nonlinear fatigue damage accumulation model which is applied to predict fatigue life under two-stress level loading and reliability prediction under multi-stress level loading. The results show that the proposed method has a good agreement between the experimental data and predicted values.

Luminescence analysis of damage accumulation; case study of calcium molybdate

A comparative study of damage accumulation in calcium molybdate (CaMoO4) has been conducted using Rutherford Backscattering/Channeling (RBS/C), cathodoluminescence (CL) and ionoluminescence (IL) techniques. All methods used confirm a two-step character of damage build-up process. Similar threshold fluence values have been extracted from RBS/C, CL and IL measurements. This analysis confirms the huge potential of luminescence techniques for damage analysis in single- and polycrystalline samples and the ability of the IL method to perform fast, in situ analysis of damage accumulation process.

Analysis of Micro-Elastohydrodynamic Lubrication and Prediction of Surface Fatigue Damage in Micropitting Tests on Helical Gears

The paper describes results obtained from the micro-elastohydrodynamic lubrication (micro-EHL) modeling of the gear tooth contacts used in micropitting tests together with a contact fatigue and damage accumulation analysis of the surfaces involved. Tooth surface profiles were acquired from pairs of helical test gears and micro-EHL simulations were performed corresponding to surfaces that actually came into contact during the meshing cycle. Plane strain fatigue and damage accumulation analysis shows that the predicted damage is concentrated close to the tooth surfaces and this supports the view that micropitting arises from fatigue at the asperity contact level. A comparison of the micropitting performance of gears finish-ground by two alternative processes (generation-grinding and form-grinding) suggests that 3D “waviness” may be an important factor in explaining their different micropitting behavior.

Stochastic Model for Damage Accumulation in Rubble-Mound Breakwaters Based on Compatibility Conditions and the Central Limit Theorem

AbstractMotivated by existing damage accumulation modeling difficulties, some suggestions on how to build consistent stochastic models for damage accumulation in breakwaters are given. The models avoid the selection of easy to use mathematical functions, which are replaced by those resulting from a set of properties that are expected in the model. It is shown how an inadequate selection of damage progression models leads to inconsistencies, which are avoided by using the proposed consistent mathematical structures. Dimensional analysis, compatibility conditions, and the central limit theorem are the bases for building a model aimed at reproducing the stochastic damage progression on breakwater as a result of general random wave actions. Four elements are identified as essential for a damage accumulation analysis: (1) the statistical distribution of the initial damage, (2) the mathematical structure of damage growth curves, (3) the damage function, which accounts for how the variables affect damage, and (4...

Physics based Prognostics of Solder Joints in Avionics

Applicability of a physics based prognostics approach for solder joints using microstructural damage models is investigated. A modified deformation mechanism map for the solder alloys is introduced where grain boundary sliding (GBS) plays a dominant role during creep deformation. The high homologous temperature of solder as well as the combined thermal-vibration cycling experienced during typical operating missions necessitates the use of a combined creep-fatigue failure approach. In this work, a PCB consisting of a heat generating chip with Ball-Grid Array (BGA) solder joints is considered for avionics application. A prognostics based Life Cycle Management approach was used to perform the mission analysis, FEA, thermal-mechanical stress analysis and damage accumulation analysis. The remaining useful life (RUL) is predicted for different rupture strains. The uniqueness of this approach lies in the use of microstructure based damage models and consideration of both material and mission variability to predict the RUL under actual usage. The life critical nodes were observed near the junction of the solder joints with the substrate due to high disparities in their coefficients of thermal expansion. In addition, the probabilistic analysis was also performed by randomly varying the grain size and fitting a two-parameter Weibull distribution to the failure data. The model calibration and the results show some practical trends that need to be verified through future experimentation. The simulation results demonstrate the viability of using a physics-based approach for the prognosis of solder joint failures in avionics.

Finite element analysis of damage accumulation for structure under impact

Responses of structure under impact load are different from quasi-static process and fatigue. Especially when the impact load is cyclic loading and unloading, damage of structure is different form that of structure under single continuous load. Random impact load usually has high peak value, thus material in structure may contain plastic strain, and damage evolution is non-linear. For cyclic loading and unloading, elastic recovery process should be considered. These characteristics make it difficult to compute damage in FEA. In the paper, we use FEM and damage theories to compute cumulative damage of certain metal structure under cyclic loading and unloading, and statistic method is used in load setting. A series of experiments were carried out to verify the simulated results. It is proved that FEM can be used to acquire cumulative damage of structure under cyclic loading and unloading, and the results may be referenced in engineering design.

Evolution of blast-induced rock damage and fragmentation prediction

A detailed understanding of blasting induced rock damage and fragmentation process is important to blasting design and parameter optimization. Due to the complexity of rock property and damage evolution, it is useful to deal with such problems through statistical methods. In this study, according to the critical fracture characteristic and the relationship between crack density and damage variable, a damage evolution equation under statistical damage mechanics network is suggested by considering the effect of loading rate and initial damage in rock. Based on percolation theory and renormalization group method, critical property of rock damage is analyzed. In order to give a quantitative description for the distribution of fragments, a fractal analysis of damage accumulation is made, and a fractal prediction method of fragmentation resulting from rock blasting is presented.

Creep sagging analysis of pressure pipes II: Damage accumulation under variable temperature and pressure conditions

The problem of non-linear stress analysis of creeping reinforced pipes under constant pressure has been treated in a recent work [1]. In the present work, a damage accumulation analysis of the above problem is attempted taking into account the non-linear distribution of the stresses as well as non-linear damage accumulation under variable pressure and/or temperature conditions. For the stress analysis a non-linear differential equation is used to derive the stress concentration in critical locations of power pipes reinforced by rigid rings which are distributed along their axis. Due to step-wised temperature and internal pressure of the pipe, the damage accumulation is predicted by using a damage function specified with respect to damage parameter derived by the stress versus Larson–Miller coefficient curve. Advantages of the proposed methodology are:(a)the 2-D creep stress analysis incorporates mechanical behaviours of material derived by uniaxial tests,(b)the predicted damage accumulation due to the variable pressure takes into account the previous damage history as well as the loading order effect.