Fatigue Curves Research Articles

Comparing different fatigue test methods at asphalt mastic level

Latest research is focused on predicting the fatigue behavior of asphalt mixtures through cost-effective and simple test methods on asphalt mastic level (asphalt binder + mineral fines). There are numerous fatigue test methods for asphalt binders and mastic using the dynamic shear rheometer (DSR). However, up to now, the results of the different fatigue tests on DSR have not been directly compared. Therefore, four different asphalt mastic mixes were prepared, and each was tested with the two most popular fatigue tests [linear amplitude sweep (LAS) test and time sweep (TS) test] and then compared to each other. The TS tests were performed as stress-controlled and as strain-controlled tests. All LAS and TS tests were performed with cylindrical and hyperbolic specimen shapes to identify impact of specimen shape. Different fatigue criteria were applied for evaluation to investigate the comparability of the results. Stress-controlled TS tests, strain-controlled TS tests, and LAS tests reveal different rankings of fatigue performance. However, a dissipated energy approach can combine stress-controlled and strain-controlled TS tests into one fatigue curve. The hyperbolic specimen shape can be used for TS tests and results in the same rankings. The hyperbolic specimen shape is not applicable for LAS tests. A calculation model could be derived to establish a relationship between the measured and actual stresses and strains in the necking of a hyperbolic specimen. TS tests using the dissipated energy approach appear to be the most promising mastic fatigue tests.

The Mathematical Simulation for the Photocatalytic Fatigue of Polymer Nanocomposites Using the Monte Carlo Methods

We consider an approach to mathematical modeling of photodegradation of polymer nanocomposites with photoactive additives using the Monte Carlo methods. We principally pay attention to the strength decrease of these materials under solar light action. We propose a new term, “photocatalytic fatigue”, which we apply to the particular case when the mechanical strength decreases only owing to the presence of photocatalytically active components in polymeric nanocomposite material. The propriety of the term is based on a relative similarity of photostimulated mechanical destructive processes in nanocomposites with photoactive additives and mechanical destructive processes typical for metal high-cycle fatigue. Formation of the stress concentrations is one of the major causes of fatigue cracks generation in metals. Photocatalytic active nanoparticles of semiconductors initiate a generation of the stress concentrations under sunlight irradiation. The proposed mathematical model is a Wöhler curve analog for the metal high-cycle fatigue. We assume that equations for high-cycle fatigue curves of samples with stress concentrations could be used in mathematical modeling of polymer nanocomposites photodegradation. In this way, we replace the number of loading cycles with the exposition time in the equations. In the case of polypropylene and polyester samples with photoactive titanium dioxide, the experimental parameters of phenomenological equations for “photocatalytic fatigue” are calculated using one of the Monte Carlo methods based on the random search algorithm. The calculating scheme includes a solution of the extreme task of finding of the minimum of nonnegative transcendent multivariable function, which is a relative average quadratic deviation of calculated values of polymeric nanocomposite stress in comparison with corresponding experimental values. The applicability of the “photocatalytic fatigue” model for polymer nanocomposites with photoactive nanoparticles is confirmed by the example of polypropylene and polyester samples. The approximation error of the experimental strength values for them did not exceed 2%.

A benchmark activity on the fatigue life assessment of AlSi10Mg components manufactured by L-PBF

One of the challenges associated with additive manufacturing (AM) is the definition of an assessment route which considers the main process signatures of the AM process. To this end, this work presents a complete benchmark activity for the assessment of an AlSi10Mg component produced by a laser powder bed fusion process, aimed at advancing the understanding of the fatigue resistance of AM materials with particular focus on the comparison between the fatigue performances of small coupons and demonstrators. Four builds of AlSi10Mg specimen geometries were manufactured to: (i) determine the fatigue curves for both as-built and machined conditions; (ii) measure the fatigue crack growth rate; (iii) produce and test under fatigue a benchmark component used as a reference for the validation of the fatigue assessment procedure. Tools and concepts of flaw tolerance were then used to perform the fatigue assessment of the benchmark component and were shown to be successful in the life prediction. Results obtained from this wide database (related to internal defects and surface features) show that only a fracture-based fatigue assessment is able to provide precise life estimates consistent with material crack growth properties. Eventually, all the experimental results including specimens design, analysis of fracture surfaces and raw tests’ data will be made available in a database which can be accessed and used by the industrial and scientific communities to calibrate and validate alternative fatigue assessment procedures of AM parts.

Fatigue behavior of rib-to-floorbeam welded connections in UHPC reinforced OSDs subjected to longitudinal flexural

In recent years, ultra-high-performance concrete (UHPC) has been extensively used in orthotropic steel decks (OSDs) to improve their structural characteristics and extend their fatigue lives. In the present study, an experimental investigation was conducted on three full-scale rib-to-floorbeam welded connections to study the influence of utilizing UHPC overlay on fatigue behavior of such welded connection in OSDs. Two rear axle loads of HL-93 fatigue truck codified in the AASHTO specification were applied in the tests and the effect of longitudinal flexural were considered. Fatigue tests were conducted with full fatigue performance including the failure modes, crack initiation and propagation paths, fatigue lives, and vertical rigidity degradations fully reported. The obtained fatigue test results demonstrated that the application of UHPC overlay remarkably extended the fatigue life of the studied rib-to-floorbeam connections; the fatigue lives at the test end (Nf) were extended by 74.6% under the effect of the same hot spot stress range. The vertical rigidity of the two UHPC reinforced specimens were degraded by 12.3% and 7.3% compared to 15.1% for the unreinforced specimen, indicating that the UHPC reinforced specimens still have considerable load-carrying capacities until the fatigue failure. Moreover, it is demonstrated that the FAT100 fatigue curve provided in IIW fatigue design recommendations could be employed to predict the fatigue resistance of rib-to-floorbeam welded joints in OSDs.

Features of fatigue and damage-tolerance tests of full-scale metal-composite aircraft structures

The main features of the mechanisms of damage during cyclic loading of metal and composite materials have been studied. The results obtained are used to develop the approaches to fatigue and damage tolerance tests of metal-composite (hybrid) structures to confirm their safe operation. It is shown that composites exhibit higher scattering characteristics compared to metals due to their heterogeneity attributed to the anisotropy of the material properties, the presence of technological defects and various natural inhomogeneities in their structure, both in terms of static and fatigue properties. This leads to the necessity of testing two identical full-scale structures: one to confirm the service life of the metal part, and the other of the composite part. The fatigue tests of structures should be carried out for different ranges of variable loads, which differ in the size of the block of variable loads, the levels of «high» and «small» loads and the load enhancement coefficient. To carry out fatigue tests of the composite part of the structure during an acceptable time, it is necessary either to increase the loads of the variable loading spectrum, or to introduce additional «overload» cycles. Proceeding from the condition of the equality of the probabilities of non-destruction for the metal and composite parts of the structure, the relations for determination of the load enhancement coefficient k σ and the number of «overload» cycles n are obtained. The load enhancement coefficient is determined by the ratio: , where m c and m m are the exponents of fatigue curves of the composite and metal, η c and η m are the reliability coefficients when testing composite and metal parts. The required number of «overload» cycles is determined by the ratio: where σ eq o , σ eq are the equivalent stresses of the overload cycle and the spectrum of variable loads.

Probabilistic Fatigue Fragility Curves for Overhead Transmission Line Conductor-Clamp Assemblies

The residual life of transmission line overhead conductors under conditions of fretting fatigue is an important asset management issue for electric network operators. The current industry practice for overhead conductor residual life estimation relies heavily on experimentally generated fatigue curves or rule-based expert systems. The current experiment-based methods do not consider specific conductor-clamp configurations and are based on the simple flexion model. This approach results in large uncertainties in service life predictions and are limited to a failure criterion based on the first wire failure in the conductor. Rule-based expert systems also have limited applicability since they lack physical representation of the fretting fatigue process. Given the limitations of the current methods, the objective of this work is to propose a framework that combines physics-based models and probability theory to estimate the residual life of overhead conductors considering either single or multiple wire failure criteria. To illustrate this procedure, a finite element model of a Bersfort conductor-clamp system is used to assess the contact conditions and internal stress states in the wires of the conductor. Results from the numerical model are then used to develop a fretting fatigue criterion that is a function of the contact energy dissipation mechanisms, contact stresses, and the plain fatigue resistance of the wires. Probability of failure of each contact point between wires and between wires and clamp is computed using the fretting fatigue criterion. With this information, the most probable locations of fretting fatigue failure are identified in the conductor. The predictions for the locations of failure are validated with available literature data for the same conductor-clamp configuration. Given the probabilities of failures at each contact point, the probability of failure of the conductor is derived with the Poisson binomial distribution. Fragility curves are presented for the first through the third wire failures in the conductor. The fragility curves are validated through comparisons with available literature data on the same conductor-clamp configuration. Fatigue curves are also generated from the fragility model for the first wire failure and compared against experimentally generated fatigue curves.

Defect tolerant fatigue assessment of AM materials: Size effect and probabilistic prospects

Despite the significant advantages such as rapid prototyping of complex structures, engineering application of Additive Manufacturing (AM) technique has been limited due to the weak fatigue performance and lacking of fatigue design rules of AM parts. Particularly, this application relies on the improvement of AM processing technique and integrity assessment of AM parts, the latter usually demands costly and time-consuming fatigue tests, especially for full-scale tests. Accordingly, the size effect and fatigue performance scatter in AM materials are explored on basis of defect data scanned by CT and experimental data in this work. Firstly, the distribution of maximum defects of AM materials under size effect is extrapolated via extreme value statistics theory; then a strength altering factor is proposed to characterize the effect of defects on fatigue scatter and size effect. From essential structure of fatigue curves, the relationship among defects, fatigue strength and fatigue curves are quantitatively analysed to extrapolate the probabilistic fatigue curves for AM materials; finally, three series of AlSi10Mg specimens with different processing parameters and gauge volumes prove the method effectiveness that the “location” and “scale” of fatigue curves is successfully predicted, and defect-tolerant assessment for AM parts is performed by employing the predicted fatigue curves.

Polymer gear contact fatigue reliability evaluation with small data set based on machine learning

AbstractPolymer gears have shown potential in power transmission by their comprehensive mechanical properties. One of the significant concerns with expanding their applications is the deficiency of reliability evaluation methods considering small data set circumstances. This work conducts a fair number of polyoxymethylene (POM) gear durability tests with adjustable loading and lubrication conditions via a gear durability test rig. A novel machine learning-based reliability model is developed to evaluate contact fatigue reliability for the POM gears with such a data set. Results reveal that the model predicts reasonable POM gear contact fatigue curves of reliability–stress–number of cycles with 2.0% relative error and 18.8% reduction of test specimens compared with the large sample data case. In contrast to grease lubrication, the oil-lubricated POM gear contact fatigue strength improves by 10.4% from 52.1 to 57.6 MPa.

Study of the fatigue strength of steel 09G2S obtained by 3D printing based electric arc welding in a wide range of low temperatures

In this work, we consider the issues of obtaining workpieces from cold-resistant steel 09Mn2Si by a promising method of 3D-printing by electric arc surfacing (electric arc additive growing). The task of assessing the mechanical properties of the obtained material and understanding the process of its destruction is urgent. The assessment of the fatigue strength of the obtained material after deposition and after subsequent heat treatment (HT) (normalization) in a wide range of low temperatures is carried out. A fractographic analysis of fatigue fractures of 9Mn2Si steel using scanning electron microscopy was also carried out. Ultimately, this makes it possible to assess the reliability of parts manufactured by 3D-printing arc welding. In the course of the work, the mechanical properties were obtained and the analysis of the curves of low-cycle fatigue of the samples after 3D-printing and after further HT in the temperature range of -60 ... 20 °C was carried out. Metallographic studies have been carried out and structural changes have been established in the process of fatigue loading at different operating time of the sample. A relationship was established between the value of the maximum cycle stress and the operating time corresponding to the onset of the onset of the main crack and the moment of fracture of the sample for steel 9Mn2Si steel. The dependence of the average growth rate of the main crack on the applied stress during fatigue tests is obtained.

Defect‐induced fatigue scattering and assessment of additively manufactured 300M-AerMet100 steel: An investigation based on experiments and machine learning

Additive manufacturing (AM) has attracted much attention recently for its immanent advantages. Assessment of the fatigue performance for AM treated materials becomes vital for both material science and engineering applications. In this study, we extensively investigate the fatigue performance of AM processed 300M-AerMet100 steel by combining experiments, numerical simulations and machine learning. We conduct experiments to obtain fatigue curves as calibration and to determine the parameters used in the theoretical models. Continuum damage mechanics-based fatigue models are presented and numerically implemented to generate sufficient training data for machine learning. We then employ a multi-layer perceptron neural network model to predict the fatigue life of the AM processed 300M-AerMet100 steel. Experimental results show that there are scatters in the fatigue data, which may be caused by the small cracks induced by the laser cladding process via fractographic analyses. Numerical results show that a good prediction of fatigue life can be achieved by combining the continuum damage mechanics-based fatigue models and the multi-layer perceptron neural network model. This work provides a systematic prediction platform for the fatigue performance of the AM fabricated 300M-AerMet100 steel.

Оцінка втомної міцності при асиметричному циклі навантаження

The object of study in the article is the individual parts of aircraft units, applied to loads that change over time. The subject of study is models that describe fatigue resistance under asymmetric loads. The goal is to develop a fairly simple engineering technique for detecting parts of aircraft units operating under an asymmetric loading cycle. Tasks: general analysis of many approaches to design cycles before the destruction of parts of aircraft units, production with an asymmetric loading cycle; select calculations acceptable for practical calculations, determine the endurance limit under a symmetrical loading cycle for steels and aluminum alloys used in aircraft units; select a calculation to calculate the maximum amount of asymmetric cycle. Methods used engineering analysis of methods for constructing a fatigue curve for an asymmetric speed change cycle; calculation of the endurance limit for a symmetrical cycle of change depending on the properties of materials based on the results of experimental selection and calculation of the endurance limit of materials to calculate the endurance limits of materials; the finite element method for counting and increasing dimensions in parts in the Simulation software package in Solidworks packages. The obtained results are obtained: an equation is chosen for the structure of the curve with an asymmetric cycle of stress change, given mechanical properties of the material; selections are selected for calculation with acceptable accuracy according to the specified properties of the endurance limits of materials with a symmetrical loading cycle of steels and aluminum alloys used in aircraft units; calculations were selected to calculate the limiting value of the asymmetric oscillation of the cycle; a method for determining the constants of the Weibull distribution for the fatigue curve under an asymmetric load cycle is proposed. Conclusion: an engineering technique has been developed for determining the resistance of parts of aircraft units operating under loads that change over time according to an asymmetric cycle.

Unified characterizing fatigue performance of high modulus asphalt concretes under diverse stress state

As a new material, high modulus asphalt concrete (HMAC) with good durability is widely used in the pavement engineering. One of the most critical performance indexes of HMAC is the fatigue cracking. However, in the experiment of evaluating the fatigue properties, different anti-fatigue effects are obtained only by adding different modifiers. In addition, using only one loading mode to determine the fatigue properties of HMAC neglects the fact that there is a difference among the fatigue test results in various loading modes, which artificially leads to the non-uniqueness and unscientific design of high modulus asphalt pavements for the fatigue resistance. Therefore, four internationally accepted mainstream strength tests at different loading rates, including direct tension, indirect tension, unconfined compression and four-point bending tests, were carried out to enhance the veracity of structural resistance design of high modulus asphalt pavements. It is revealed that the fitted curve for the variation of strength with loading rate is a power function with velocity dependence, and the models for direct tension, indirect tension, unconfined compression, and four-point bending strengths established as a function of loading rate are SD = 3.218v0.1425, ST = 3.833v0.1768, SC = 14.391v0.1130 and SF = 7.839v0.1489 respectively. Besides, it is shown that the conventional S-N fatigue equation does not take into account the velocity dependence of the strength of HMAC in the stress ratios determined by the tests, and the velocity-dependent stress ratios defined in this paper are determined by the strength model and therefore take into account the viscoelasticity of HMAC. In addition, it is found that extending the fatigue curve backwards, when the fatigue life of HMAC is also close to 1, the velocity-dependent stress ratio is 1. Meanwhile, the fatigue model Nf = tv-5.318 was developed by unifying the characterization of HMAC and considering the effect of loading rate in various loading modes. It eliminated the difference of fatigue test results caused by the specimen sizes and loading modes, and effectively improved the completeness of structural design of high modulus asphalt pavements, which provided a theoretical basis for designing the high modulus asphalt pavements.

A novel estimation method for fitting fatigue data in the composite wearout model

S-N curves are used in the design of composite structures to estimate their fatigue behaviour. In this work, an empirical fatigue model has been developed based on one first proposed by Sendeckyj. To reduce the complexity of the nonlinear optimization in the Sendeckyj wearout model, a new constraint is derived based on the material S-N fatigue curve and a mathematical curve fitting. To improve the Sendeckyj model’s accuracy in all fatigue regions, a novel estimation method is used. In this method, an exponential model is used to determine the Sendeckyj model parameter for the low cycle fatigue region and a power-law model is used to determine the Sendeckyj model parameter for the high cycle fatigue region. The new model was compared against the original Sendeckyj model for glass fibre laminates with various polymer resins. The novel wearout method leads to more accurate parameters and more accurate S-N curve.

ПРИМЕНЕНИЕ НЕЧЕТКИХ ДАННЫХ В ЗАДАЧАХ ОЦЕНКИ ДОЛГОВЕЧНОСТИ

The author considers the creation of a scientifically based loading unit which would take into account the possible modes of operation in the correct proportion, with due regard for variability and unclearness (fuzziness). It is due to the fact that the fatigue damage accumulates throughout the life of the machine and must be scientifically evaluated for an adequate assessment in the probabilistic aspect. Since the operation of some specific part is not precisely defined (and cannot be determined by the logic of random use of machines during exploitation), projections of random fuzzy distributions are considered. It worked out possible to scientifically take into account a finite set of operating modes in their reasonable proportion. Analyzing the loading of a critical performance part of the rolling stock served as example for construction of distributions and in particular for estimation of the part’s resource distribution. The results obtained on the basis of the developed method will allow assessing the risks of operation and predicting the required number of spare parts. Consideration of the censored sample elements in the construction of the fatigue curve will make the estimation of the parameters of the fatigue curve more consistent. The use of fuzzy sets can be very useful when considering the fatigue curve and when evaluating the durability variation. Examples of application of the proposed approach are shown.

Probabilistic fatigue strength modelling based on various statistical approaches for a double-side welded connection

S355 steel is currently used in the fabrication of most wind turbine monopile support structures and offshore structures. In these types of structures, most fatigue failures occur in the welded connections where cyclic loading is the main responsible for this phenomenon. For the high-cycle fatigue analysis, the stress life method utilizing S-N curves can be used to determine the strength of a welded joint under fatigue loading. In this research, the evaluation of design S-N curves for a double-side welded connection made of S355 steel is proposed. This study concludes with a comparison between the experimental fatigue curves obtained and the design S-N curves at 5% and 2.3% probability of failure proposed in design codes (EN1993-1-9, DNVGL-RP-C203 standards and IIW recommendations) for offshore structures and general steel structures. For the specimens under investigation, the hot-spot and nominal stress approaches are taken into consideration. The characteristic fatigue curves of the double-side welded connection are obtained using statistical analyses based on the ASTM E739, ISO 12107, Bayesian inference, and Weibull distribution. The hot-spot and nominal stress approaches yield very similar S-N results considering the specimens under study.

Pecularities of fatigue cracks growth in steel and composite sucker rods

To predict the fatigue life of sucker rods, it is important to take into account the effect of technological environments under various loading schemes on the conditional fatigue limit of steels used for their manufacture (in particular, such as steel 20N2M), and compare these properties with modern materials for the manufacture of fiberglass and hybrid sucker rods (with metal heads and polymer rod) as prototypes of steel elements of oil-producing equipment.Specimens of sucker rods with technological or operational defects were tested for fatigue life-time in aggressive technological environments. It has been established that the fatigue life-time and fatigue endurance of sucker rods decrease with an increase in their diameter. So, with a test base of 107 loading cycles, the endurance limits of rods with a diameter of 19, 22, and 25 mm were 95, 85, and 80 MPa, respectively. It was shown that technological defects practically did not affect the life-time of the rods. Minor differences were associated with the scatter of the fatigue characteristics of the metal. Defects formed in rods during their operation in wells have a more noticeable effect on their life-time under variable loads. It was found that the resource of sucker rods with a diameter of 19 mm decreased faster compared to rods with a diameter of 22 mm in the presence of operational defects of the same depth in both rods. This is due to the greater sensitivity of smaller diameter rods to defects.According to the curves of the crack growth rate in specimens made of sucker rods with a diameter of 22 mm, it was found that the critical state (according to the jump in the crack growth rate) is reached if the crack length along the perimeter of the rods is within 15...16 mm, and its depth is 4.5 ... 5.6 mm. Such cracks were fixed at a stress range of 100 MPa, which is commensurate with the operating loads of the rods. For rods of other standard sizes, the critical crack depth, which preceded the almost spontaneous destruction of the specimens, was 3...4, 4...5 and 5...6 mm for rods with a diameter of 16, 19 and 25 mm, respectively. In article we also evaluated fatigue life on samples of fiberglass sucker rods under cyclic loading by circular cantilever bending and obtained the corresponding fatigue curves. According to the results of these tests, probabilistic curves of fatigue endurance of samples with steel and fiberglass sucker rods in the technological environment of reservoir water were constructed with different probability of their non-destruction P(N). Fatigue endurance of samples with steel, fiberglass and hybrid sucker rods was compared.

Measuring Orthopedic Plate Strain to Track Bone Healing Using a Fluidic Sensor Read via Plain Radiography.

We describe a fluidic X-ray visualized strain indicator under applied load (X-VISUAL) to quantify orthopedic plate strain and inform rehabilitative care. The sensor comprises a polymeric device with a fluidic reservoir filled with a radio-dense fluid (cesium acetate) and an adjoining capillary wherein the liquid level is measured. A stainless-steel lever attaches to the plate and presses upon the acrylic bulb with a displacement proportional to plate bending strain. The sensor was attached to a plate in a Sawbones composite tibia mimic and a human cadaveric tibia. An osteotomy model (5 mm gap) was used to simulate an unstable fracture, and allograft repair to simulate a stiffer healed fracture. The cadaveric and Sawbones tibia were cyclically loaded five times (0-400 N) using a mechanical test stand, and fluid displacement was measured from plain radiographs. The sensor displayed reversible and repeatable behavior with a slope of 0.096 mm/kg and fluid level noise of 50-80 micrometer (equivalent to 5-10 N). The allograft-repaired composite fracture was 13 times stiffer than the unstable fracture. An analysis of prior external fracture fixation studies and fatigue curves for internal plates indicates that the threshold for safe weight bearing should be 1/5th-1/10th of the initial bending for an unstable fracture. The precision of our device (<2% body weight) should thus be sufficient to track fracture healing from unstable through safe weight bearing. The X-VISUAL fluidic sensor enables orthopedic plate strain quantification to monitor facture healing via X-ray imaging.

Assessing the Compression Fatigue of the Welded Test Specimens

The focus of this paper is on compression fatigue life in welded test specimen. Considered test specimen is highly complex due to multi-layer welding and production errors affecting its topology. Test specimen is made from S355 steel which is used for both base material and weld. Compression fatigue analysis is seldom performed as compression positively affects fatigue life. At the same time, during MAG welding residual stresses affect the fatigue life, decreasing it significantly. Finite element method (FEM) is applied to estimate compression fatigue life of the welded test specimen and obtained fatigue curve is compared to the experimental curve. Experimental curves are given for different stress ratios: R= -1, and R= - ∞. Analysis consists of thermal and structural analysis using FEM method and fatigue analysis which is based on FEM results. FEM thermal simulation of welding with constant initial temperature is performed first and followed by nonlinear structural analysis for assessment of the residual stresses due to heat expansion. Fatigue parameters are determined using Universal slope method.

Design, analysis and experimental qualification of gripper bellows for FBTR control rod drive mechanism

The design of welded-disc bellows is not addressed in any design codes or standards. This paper discusses the design, analysis and experimental validation of the gripper bellows used in the control rod drive mechanisms of fast breeder test reactor. The material of construction of the bellows is 0.125 mm thick AM350-SCT1000. The design fatigue curve of the material at 803 K is not available in open literature. The fatigue curve of the material (Coffin-Manson's relation) was generated from the tensile testing data using four-point correlation method and universal slopes method. Elasto-plastic finite element analysis of the bellows was carried out and fatigue life of the bellows was estimated numerically. A factor of safety of 20 on number of cycles was used as suggested in codes such as ASME section-III and RCC-MR. Experimental qualification of the bellows as per ASME section-III, appendix-II was carried by testing of the bellows in sodium at 803 K.

Прогнозирование долговечности паяных контактных соединений микросхем

The study is aimed at developing a nondestructive testing method for electronic equipment and its components. This method allows one to identify critical design defects of printed circuit boards (PCB) and to predict their service life taking into account the nature of probable operating loads. The study uses an acoustic emission method to identify and localize critical design defects of printed circuit boards. Geometric dimensions of detected critical defects can be determined by X-ray tomography. Based on the results of the study, a method combining acoustic emission and X-ray tomography has been developed for nondestructive testing of printed circuit boards. The stress-strain state of solder joints containing detected defects is analyzed. Durability is predicted using the damage function of the material, experimental fatigue curve with allowance for rheological properties of materials, the temperature effects, and complex stress-strain state. The results of using the developed method for estimating the degree of damage of the electronic board have been verified based on the experimental results of studies carried out in accordance with IPC-9701. The prediction error does not exceed 5%. Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.