Damage Process Research Articles

Sliding Contact Fatigue Damage of Metallic Implants in a Simulated Body Fluid Environment

At the modular interface of the joint implants, repeated contact stresses in a corrosive synovial environment cause surface degradation that worsens over time. The lubricating mechanisms at the joints are altered by the deteriorated synovial fluid by the wear debris and corrosion products. As a result, the joint implants’ unsatisfactory performance will be exacerbated by the synergistic combination of wear and corrosion. In this work, reciprocal sliding contact tests in simulated synovial fluid were conducted on the two main metallic implant materials, CoCrMo and Ti6Al4V. The mechanical and electrochemical reactions were described by monitoring the open-circuit potential (OCP) and coefficient of friction (COF). The electrochemical damage that altered the oxidation chemistry on both surfaces was illustrated by the potentiostatic test findings. The surface damage process of CoCrMo under all contact loads presented unstable chemomechanical responses. On the other hand, the Ti6Al4V results revealed a moderate decrease in fretting current and stable changes in the coefficient of friction. Consequently, the experimental investigation determined that, when mechanical loadings and electrochemical stimulus are combined, Ti6Al4V’s biocompatibility would be superior to CoCrMo’s.

Influence of surface integrity on short crack growth behavior in HFMI-treated welded joints

AbstractThis study investigates the influence of surface integrity and the localized fatigue phenomena on the initiation and propagation of short fatigue cracks in high-frequency mechanical impact (HFMI)-treated welded joints. The treated surface region, characterized by a compressive residual stress field, smooth notch geometry, and work hardening layer, improves welded joints’ fatigue strength. However, how these surface conditions influence the fatigue damage process zone during short crack initiation and growth is not yet well known. Therefore, this study systematically investigates the influence of different surface characteristics on fatigue life modeling of HFMI-treated welded joints made of high-strength steel. This is achieved using a non-local continuum damage mechanics-based approach of crack growth and elastic–plastic finite element simulation, explicitly modeling treated surface conditions. The simulated fatigue life is first verified with experiments and then applied to various surface conditions. The simulation results show that most of the fatigue life is spent until a crack size of 0.2 mm. The compressive residual stress field greatly extends both short crack initiation and propagation life, with its degree of contribution highly dependent on loading history and residual stress change. The role of the work hardening layer is mainly concentrated on improving fatigue life during short crack initiation and the very beginning of short crack growth.

Stud-concrete interactional model of shear connectors in steel-concrete composite structures

A theoretical calculation method, named stud-concrete interactional model, of load-slip relationship of stud shear connectors in composite structures is presented. This model has been developed based on the elastic foundation beam theory and considers the different stress states of the concrete around studs during the damage process. Two important stud-concrete interaction parameters, called equivalent spring stiffness and yielding slip, are introduced for the first time to quantify the shear contribution of concrete and the relative slip between stud and concrete, respectively. The range of yielding slip has been determined based on a force-flow model and a finite element model. The proposed stud-concrete interactional model has been utilized to derive the load-slip formula considering the elastic, elastoplastic, and plastic stages of stud shear connectors. Experimental results show that the proposed formula are valid and outperform existing formulas. This paper offers new insight into the shear behavior of stud shear connectors.

Anticathode effect on electron kinetics in electron beam generated E × B plasma

Abstract Electron beam (e-beam) generated plasmas with applied crossed electric and magnetic (E×B) fields are promising for low damage processing of materials with applications to microelectronics and quantum information systems. In cylindrical e-beam E×B plasmas, radial confinement of electrons and ions is achieved by an axial magnetic field and radial electric field, respectively. To control the axial confinement of electrons, such e-beam generated plasma sources may incorporate a conducting boundary known as an anticathode, which is placed on the axially opposite side of the plasma from the cathode. In this work, it is shown that varying the anticathode voltage bias can control the degree to which the anticathode collects or repels incident electrons, allowing control of warm electron (electron energies in 10-30 eV range) and beam electron population confinement. It is suggested that the effect of the anticathode bias on the formation of these distinct electron populations is also associated with the transition between weak turbulence and strong Langmuir turbulence.

Study on dynamic mechanical characteristics of specimens with cavity under prestressing conditions

Deep defect-bearing rock bodies are typically subjected to in-situ stresses and dynamic loading. This study investigates the failure characteristics of cavity specimens containing square holes and circular holes by employing different static-dynamic coupled loading experiments using a triaxial SHPB device that can facilitate static-dynamic coupled loading. Based on SHPB experiments, strain field analysis, and 3D laser scanning modelling techniques, this study comparatively analyses the effects of impact velocity and stress environment on the strength, stress–strain curve characteristics, dynamic damage process, and damage characteristics of square and circular hole specimens. The experiment proposes using elevation maps to characterise the damage characteristics of the specimen under impact loading. It ultimately relates the experimental results to field rockbursts and tunnel excavation, which has significant implications for guiding field practice to a certain extent. The experimental results showed that the stress environment under dynamic perturbation has a bidirectional effect (both favourable and unfavourable) on the strength of the specimens containing defects, which manifests as a difference in the characteristics of the stress–strain curves. When damage occurs near the cavity of the specimen, the stress–strain curve exhibits type I characteristics. When the entire specimen destabilises, the stress–strain curve shows type II characteristics. Under the same conditions, the strength of the specimens with square holes is significantly lower than those with circular holes. The 3D laser scanning results indicated that the damage is primarily concentrated near the cavity, and compared to the circular hole specimen, the damage area of the square hole specimen is mainly attributed to shear-tension damage, resulting in the collapse of the slabs on the upper and lower sides of the cavity.

Mechanical behavior of clayey methane hydrate-bearing sediment: Effects of pore size and physicochemical characteristics using a novel DEM contact model

The mechanical behavior of Methane Hydrate-Bearing Sediment (MHBS) is essential for the safe exploitation of Methane Hydrate (MH). In particular, the pore size and physicochemical characteristics of MHBS significantly influence its mechanical behavior, especially in clayey grain-cementing type MHBS. This study employs the Distinct Element Method (DEM) to investigate both the macroscopic and microscopic mechanical behavior of clayey grain-cementing type MHBS, focusing on variations in pore size and physicochemical characteristics. To accomplish this, we propose a Thermo-Hydro-Mechanical-Chemical-Soil Characteristics (THMCS) DEM contact model that incorporates the effects of pore size and physicochemical characteristics on the strength and modulus of MH. This THMCS model is validated using experimental data available in the literature. Using the proposed contact model, we conducted a series of investigations to explore the mechanical behavior of MHBS under conventional loading paths, including isotropic and drained triaxial tests using the DEM. The numerical results indicate that smaller pore sizes and lower water content—key physicochemical characteristics resulting from variations in electrochemical properties and the intensity of the electric field—can lead to reduced shear strength and stiffness due to the increased breakage of aggregates and weakened cementation. Additionally, heating was found to further accelerate the process of structural damage in MHBS.

Acoustic emission evolution and fracture mechanism of rock for direct tensile failure

The failure mechanisms of engineering rock masses primarily involve tensile and shear failure. Differentiating between the acoustic emission (AE) signals generated during the tensile and shear damage processes in rock can provide a scientific basis for the classification of acoustic signals in field rock fracture monitoring. This paper presents a study on acoustic emission monitoring during the direct tensile testing of granite, proposing a method for classifying AE signals based on the damage and failure processes of the samples. Additionally, the classification of tensile and shear AE signals is explored. The main conclusions are as follows. The proportion of low-frequency signals (frequency <200 kHz) and high-frequency signals (frequency >200 kHz) in all AE signals was found to be 81.6 % and 19.4 %, respectively. Based on an integrated classification and statistical method for AE signals in rock tensile failure, which involves steps such as “denoising the raw waveform, time-frequency domain data transformation, fuzzification processing, extraction of dominant frequency and corresponding amplitude, and identification of secondary dominant frequencies,” the AE signals were categorized into two types, A and B. Type A signals accounted for an average of 7.6 %, while Type B signals made up 92.4 %. Based on the polarity determination method, the focal mechanisms of AE (Acoustic Emission) events were identified. In tensile events, the average proportion of Type A signals was 8.34 %, while the average proportion of Type B signals was 91.66 %. The Brazilian splitting test also yielded classification results similar to those obtained from direct tensile testing. Thus, it was preliminarily concluded that Type A signals, characterized by the presence of both a primary and secondary frequency, correspond to shear signals, whereas Type B signals, which only exhibit a primary frequency without a secondary frequency, correspond to tensile signals.

Dynamic Mechanical Properties and Damage Morphology Analysis of Concrete with Different Aggregates Based on FDM-DEM Coupling

To study the dynamic compressive mechanical properties of concrete with different aggregates (limonite and lead-zinc ore), a dynamic mechanical experiment was carried out by the Φ 100 mm SHPB equipment. Based on the coupling of the finite difference method (FDM) and the discrete element method (DEM), a three-dimensional numerical model was constructed. The effects of various strain rates and aggregate types on the dynamic mechanical properties of concrete, the dynamic increase factor (DIF), and the dynamic impact damage process were analyzed and discussed. The results show that both types of concrete have a significant strain rate strengthening effect. The dynamic compressive strength, peak strain, and DIF of the two types of concrete gradually increase with the increasing strain rate. The DIF and dynamic compressive strength growth of lead-zinc ore concrete was greater than that of limonite concrete, and the strain rate sensitivity of lead-zinc ore concrete was stronger than that of limonite concrete. The constructed three-dimensional coupling model can better simulate the experimental process, and the stress-strain curves and damage patterns show good agreement with the experimental results. The relative errors between the calibration results of the microscopic parameters and the experiment values are all within 1%.

Experimental and Numerical Study of Wrought Inconel 718 Under Thermal Cycles of Variable Amplitude Coupled with Mechanical Loading

In this paper, a pulsed laser is applied to realize these complicated thermal cycles experimentally, coupling with the constant mechanical loading with the self-designed sample holder. A numerical simulation model is proposed to calculate the temperature and stress under thermal cycles of variable amplitude coupled with mechanical loading. The findings indicate a strong correlation between the measured temperature curve and the simulated results under various loading parameters. It is observed that the calculated depth of thermal–structural interaction for low-cycle conditions exceeds that of high-cycle conditions. In addition, the mechanism of crack evolution under thermal cycles of variable amplitude coupled with mechanical loading is discussed. This paper offers extensive experimental and numerical perspectives on the damage process occurring under thermal cycles of varying amplitudes combined with mechanical loading, highlighting its substantial engineering importance for conducting failure analyses and optimizing the design of hot-end components.

Pull-Out Progressive Damage and Failure Analysis of Laminated Composite Bolted Joints

Laminated composite bolted joints are increasingly used in the aerospace field, and their damage and failure behavior has been studied in depth. In view of the complexity and stability requirements of laminated composite bolted structures, accurate prediction of damage evolution and failure behavior is significant to ensure the safety and reliability of the structures. In this paper, a novel asymptotic damage model is developed to predict the damage process and failure behavior of laminated composite bolted joints. In this model, the modified Puck criterion and the maximum shear stress criterion are used for fiber yarns. The parabolic yield criterion is adopted for the matrix, and the fiber fracture, inter-fiber fracture and matrix fracture are considered at the microscopic level. The pull-out strength and progressive failure behavior of countersunk and convex bolted joints structures are predicted by using the proposed model, and the corresponding experimental studies are carried out. The results show that the prediction results are in good agreement with the experimental data, which verifies the reliability of the model. Additionally, the effects of different structural parameters (thickness and aperture) on the progressive damage and failure behavior during pull-out is analyzed by the proposed model, and correction factors of pull-out strength are obtained, which provides a powerful tool for the design, analysis and progression of laminated composite bolted joint structures.

Local stress/strain field analysis of die-casting Al alloys via 3D model simulation with realistic defect distribution and RVE modelling

The deformation and fracture behavior of die-casting aluminium (Al) alloys is very complex. Due to local variations in properties, the microstructure and mechanical behavior of materials are highly anisotropic. In this paper, an attempt has been made to quantitatively study the defect characteristics of high pressure cast Al alloy parts using experimental and finite element calculation methods, and to analysis the effect of local porosity and pore size on plasticity. Three-dimensional solids with real defect distribution are obtained by using 3D X-ray computed tomography, and used as an input for building a finite element model. The damage initiation of cast Al alloys under complex stress states is analyzed from micro to macro scales. Crack propagation occurs through two modes of microporous agglomeration: aggregated pores produce cracks from internal necking and stress concentration. Then, they expand in the same direction, agglomerate in a specific direction and eventually fracture. Subsequently, the effect of porosity on non-homogeneity was elucidated by obtaining local stress/strain behavior through digital image correlation measurements. Additionally, a theoretical framework of elasto-plastic deformation of microstructures and a 3D representative volume element model are developed to simulate the deformation and damage processes under cyclic boundary conditions of materials. The simulation results show that the local stress/strain around the pores evolves gradually with deformation. During the die casting process, the method demonstrates the ability to predict the mechanical behavior of Al alloys.

Evaluation of the performance and effect of steel fiber reinforced cellular concrete for underwater blast protection under contact explosion loading

The reinforced concrete structure is more likely to be destroyed under the action of underwater explosion load, which makes the overall structure have the risk of instability. The purpose of this paper is to study the underwater anti-explosion protection performance of steel fiber reinforced cellular concrete protective layer. The FEM-SPH coupling method was used to study the underwater damage process, dynamic response, failure mode and protection effect of the protected structure strengthened by eight different proportions of protective layers. The results show that the addition of steel fiber reinforced cellular concrete protective layer can effectively improve the anti-explosion performance of the protected structure, and its anti-explosion performance is directly related to the volume fraction of steel fiber in the protective layer. Under different ratio protection schemes, the total energy absorption and protection rate of the protective layer increase first and then decrease with the increase of the volume fraction of steel fiber in the protective layer, while the peak pressure of the protected structure at the measuring point and the failure volume rate of the whole structure decrease first and then increase. Among them, the underwater wave attenuation and energy consumption effect of SAP10S15 protective layer is the most prominent, and its total energy absorption is 20 % higher than that of other protective layers. Under this ratio protection scheme, the shock wave pressure of the protected structure is greatly attenuated, and the peak pressure of each measuring point is reduced by about 35.8 %, 37.9 %, 23.7 %, 27.9 % and 35.1 % respectively compared with the unprotected scheme. The damage degree of the protected structure under the SAP10S15 ratio protection scheme is significantly reduced. The failure volume rate and damage index are 8.03 % and 0.21, respectively, which are 37.7 % and 42.5 % lower than those of the unprotected scheme. The damage level is reduced from serious damage to moderate damage. In addition, the damage grade prediction curve of the protected structure is constructed, and the predicted value of the curve is in good agreement with the simulation results, which can provide a reference for the rapid evaluation of the underwater explosion-proof performance of the steel fiber reinforced cellular concrete protective layer.

Study of bond-slip performance of steel tube with UHPC based on acoustic emission parameter analysis

Conventional methods for assessing bond performance are hindered by challenges in measuring strain and a lack of sufficient sensitivity to internal structural damage. This paper examines the bond behavior between steel and ultra-high-performance concrete (UHPC) based on acoustic emission (AE). The tests included a total of 2 concrete-filled steel tube (CFST) specimens and 4 concrete-encased CFST specimens. The bonding test was analyzed using AE parameters in combination with the damage process, damage morphology, and loading curve of the test specimens. Furthermore, damage correspondence was explored for the AE parameter indexes and the bond damage indexes of the conventional method. The findings reveal that the AE peak frequencies associated with the bond failure between steel tube and concrete span 30–100 kHz, 110–130 kHz, and 220–260 kHz. The AE event rate, cumulative absolute energy, Ib-curve, and percentage of tensile cracks can be used as judgmental and early warning features for interface damage. The damage process at the interface and the concrete crack development can be characterized by the severity index HI and the severity value Sr. The measurement curves obtained from various AE sensor positions exhibit remarkable similarity. A correlation can be discerned between the severity index (Sr) of the AE and the bond damage degree (Dt) ascertained through conventional methods, effectively mirroring the structural damage progression.

A Maintenance Policy for Central Tower Receiver Subjected to Creep-Fatigue Damage

This study focuses on the central receiver of solar tower plants, which is subjected to extreme heat fluxes, high temperatures, and thermal gradients leading to degradation mechanisms such as creep, fatigue, and corrosion. Although studies in literature have developed thermal models for receiver tubes to understand the damage process and estimate their lifetime, they have not addressed the uncertainty associated with receiver damage, which arises from random operating conditions and errors in creep damage predictive models. Considering the random and varying nature of damage, this paper suggests effective maintenance strategies that optimize the receiver's lifetime and minimize maintenance costs. The strategies utilize a simulation-optimization approach and incorporate uncertain operating conditions and creep-fatigue models. The illustration case study shows that the proposed maintenance strategy can reduce the maintenance cost up to 37% versus the interval replacement of all panels.

Developing a stochastic linear elastic material model and composite laminate theory including failures, using the fiber bundle–based approach

This paper presents a novel theoretical statistical material model, which is a kind of extension of the usual 3D Hooke’s law and can take into account the damage process up to the final failure as well. This material model can provide the stress response also together with the damages to multiaxial short time alternating strain loads. It was developed by utilizing our earlier validated results of applying E-bundles for modelling stress-strain curve of different types of fibrous materials and fibre-reinforced composite sheets subjected to simple (uniaxial) mechanical loads. Based on the fiber bundle cells (FBC) theory, we introduced the so-called memory reliability functions to take into account the different changing strain loads including both the monotone, the pulsating and the alternating modes. We proved that the duplex compressive–tensile memory reliability function is the product of the compressive and the tensile memory reliability functions. Utilizing the generalized Hooke’s law and the memory reliability functions, we developed a stochastic linear elastic material law that also represents the damage and failure processes with normal and shear strain loads. This made it possible to calculate the expected value as the variance of the stress response process and determine its confidence interval at any strain load.

Investigating DNA damage caused by COVID-19 and influenza in post COVID-19.

The SARS-CoV-2 virus (termed COVID-19) was responsible for over 34 million global deaths. Although the COVID-19 pandemic has subsided, infection by emerging mutant variants of SARS-CoV-2 poses a continuing threat to public health. COVID-19 infection has been associated with the development of cytokine storm syndrome, hypercoagulability, immunological dysregulation and direct viral invasion of organs, and the long-term consequences for the health of COVID-19 survivors are currently unknown. Our research focuses on the possible mutagenic aspects of infection by COVID-19 and measures their harmful effects on DNA composition. DNA damage was investigated, using the comet assay method, during two periods: in the epidemic peak of COVID-19 and during the post-COVID-19 period, both in patients infected with COVID-19 and in those with influenza. During the epidemic peak, the levels of DNA damage ranged from the highest to the lowest levels in the following groups, respectively: intubated-ICU, non-intubated-ICU, non-ICU, and influenza, with a discernible increase in DNA damage in ICU-treated patients. The levels of DNA damage in the post-COVID-19 period were significantly lower compared to those in the epidemic peak period but there was still a discernible increase in DNA damage in the ICU group. Our results indicate that levels of DNA damage may be an effective indicator in prognostic decision-making and may therefore help to reduce mortality. Given that DNA damage and impaired repair processes can contribute to chronic diseases like diabetes, cancer, and neurodegenerative conditions, it will be crucial to investigate potential similar effects in patients with COVID-19.

Numerical simulation of stress and permeability evolution in damaged coal

Mining disturbance is the underlying cause of dynamic disasters such as coal-rock deformation, gas outbursts, and roof water inrush. Mining disturbance leads to damage in coal-rock structures and closely relates to stope cracks' distribution characteristics. Therefore, it is crucial to investigate the coupling effects of the stress field, damage field, and seepage field of coal. Firstly, we established a mechanical model considering the coupling effect of damage and elastoplasticity, which aimed to describe the softening process of coal-rock mechanical parameters and the mutation law of the permeability coefficient in the damage process. Next, we developed a pore-fracture fractal model of damaged coal. It was used to elucidate the inherent relationship between damage and pore-fracture characteristics in the process of coal-rock crushing. We then proposed a quantitative evaluation method for determining the permeability characteristics of coal under the influence of mining disturbances. Finally, a numerical simulation of damaged coal ‘s mechanical behavior and seepage characteristics under stress-seepage coupling was conducted. The development model's effectiveness was verified through comparison with experimental results. In summary, our research offered a solid scientific foundation for quantitative evaluation and accurate prediction of the evolution law of coal-rock permeability characteristics under the influence of mining disturbance.

THE ROLE OF INTRACELLULAR SIGNALING PATHWAYS IN THE DEVELOPMENT OF TROPHIC PATHOLOGIES OF THE LOWER EXTREMITIES AND THEIR REGENERATION UNDER TYPE 2 DIABETES (PART 1)

Introduction. This review article addresses the critical issue of the development and regeneration of chronic trophic ulcers in the context of type 2 diabetes. This pathological process is associated with inhibited cell proliferation, impaired differentiation of various cell types, and disrupted mechanisms that regulate cell death. An analysis of recent scientific literature also highlights the involvement of key intracellular signaling pathways in the development of chronic ulcerative pathologies of the lower extremities, as observed in both experimental animal models and patients with type II diabetes. Despite advancements, this issue remains insufficiently explored in both theory and practice, underscoring its ongoing relevance. The aim of this study is to identify the roles of key signaling pathways—transforming growth factor β (TGF-β), phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/Akt), and Wnt/β-catenin—in the inflammatory response, regenerative mechanisms, and healing processes of soft tissue damage and trophic ulcers in experimental animals and patients with type II diabetes. Materials and Methods. This study is based on an analysis of current scientific literature that addresses this topic. Results. It has been found out that changes in the content and activity of key molecules of signaling pathways lead to disruption of carbohydrate homeostasis and the occurrence of structural and functional dysfunction in damaged tissues against the background of type II diabetes. These include TGF-β, PI3K, Akt and β-catenin. Analysis of experimental data demonstrated that both under the conditions of type II diabetes development and in the occurrence of chronic ulcers of the lower extremities, against the background of this endocrine disease, there is an increase in the level of TGF-β. At the same time the activity of the PI3K/Akt signaling pathway in the above-mentioned studied groups was reduced. The relationship between the development of type II diabetes and the Wnt/β-catenin signaling pathway has been established. Suppression of its activity was accompanied by impaired regeneration of chronic trophic ulcers in type II diabetes. Conclusion. Thus, the mechanism of type II diabetes and chronic peptic ulcer disease, in the same pathology, is associated with a impaired activity of signaling cascades. This concerns the following cellular systems such as TGF-β, PI3K/Akt and Wnt/β-catenin. They can be considered as potential therapeutic targets for the development of newest methods for the treatment of chronic trophic ulcers in type II diabetes in order to accelerate the recovery process of volumetric tissue damage of the lower extremities.

Strain‐Controlled Low‐Cycle Fatigue Behavior of a Superalloy Considering Extensive Temperature Range and Stress Concentration

ABSTRACTThis study aims to investigate the low cycle fatigue (LCF) behavior and fatigue life prediction method of an advanced solid solution–strengthened nickel‐based superalloy at various temperatures and stress concentrations. Cylindrical specimens as well as plates with three types of holes (including straight holes and inclined holes with different orientations) were designed and machined for fatigue tests. The test results revealed fatigue life decreases with the temperature increasing. Meanwhile, the fatigue lives of the plate specimens have decreased differently and are strongly dependent on the geometry and orientation of the holes. The key damage parameter related to the fatigue life was found on the strain gradient path. A criterion based on strain gradient is defined as the boundary of the damage process zone. The results show that the prediction was in good agreement with the experimental data, for the majority of the data are within a scatter band of ±2.

Impact of Peritoneal Neutrophil Extracellular Traps on Peritoneal Characteristics and Technical Failure in Patients Undergoing Peritoneal Dialysis.

Peritoneal dialysis (PD) is an effective home therapy for end-stage kidney disease. However, continuous exposure to PD fluids with high glucose concentration and recurrent peritonitis may lead to the activation of cellular and molecular processes of peritoneal damage, including inflammation and fibrosis. In particular, recent studies have highlighted the role of neutrophils in chronic inflammation. This study explores how neutrophil extracellular traps (NETs) affect peritoneal membrane function and contribute to technical failures in PD patients. We conducted a prospective observational study involving 250 non-infectious and 30 acute peritonitis patients. NETs were measured using nucleosome and myeloperoxidase DNA levels in PD fluids. Monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-8 (MMP-8) were also measured to assess peritoneal inflammation and damage. A significant increase in peritoneal NETs, as determined by nucleosome and myeloperoxidase DNA levels, was observed in patients with acute peritonitis compared to patients without peritonitis. Even in non-infectious samples, NET levels were widely distributed and closely correlated with levels of MCP-1 and MMP-8. Higher levels of peritoneal NETs were closely associated with increased 4-hour dialysate/peritoneal (D/P) creatinine ratio and 1-hour D/P sodium levels, indicating a higher prevalence of fast transport and limited free water transport. These factors were associated with a higher risk of technical failure. During a mean follow-up of 34 months, 39.2% (98 patients) switched from PD to hemodialysis, with higher NET levels significantly increasing the risk by 1.9 times (95% confidence interval 1.27-2.83, p=0.020). This study suggests the importance of peritoneal NETs not only as markers of acute inflammation but also as significant immunological predictors of chronic peritoneal membrane inflammation and dysfunction, and as potential risk factors for technical failure.