Pre-stress Values Research Articles

An interpretable TFAFI-1DCNN-LSTM framework for UGW-based pre-stress identification of steel strands

Steel strands serve as the key load-bearing components of pre-stressed bridges, yet the identification of effective pre-stress for steel strands is a challenging task. In this study, a time and frequency adaptive fusion input-one dimensional convolutional neural network-long short-term memory (TFAFI-1DCNN-LSTM) framework was proposed for ultrasonic guided wave (UGW)-based effective pre-stress identification of steel strands. In this framework, the time and frequency domain signals of UGW were input into the network as two parallel branches, CNN and LSTM were utilized to extract spatial and serial-related features, and a trainable weight coefficient was introduced for adaptive fusion of time and frequency domain features. Firstly, ablation studies were conducted to investigate the influence of each key component in the proposed framework on the prediction results. Secondly, deep learning (DL) models of Res Net, Dense Net and Inception Net were introduced as comparisons, and the prediction results based on TFAFI-1DCNN-LSTM were compared with those based on the above DL models. Thirdly, the noise-robustness and performance under a few trainable samples of TFAFI-1DCNN-LSTM were also investigated. Finally, the outputs of various key layers of the proposed framework were subjected to dimensionality reduction and visualization to provide an intuitive demonstration of the feature extraction process, and the inherent mechanisms of the proposed framework were interpreted using local interpretable model-agnostic explanations (LIME). Results show that the architecture of TFAFI-1DCNN-LSTM is reasonably designed and all key components are necessary. The weights of features in time and frequency domain branches are rationally assigned due to the addition of an adaptive weight coefficient. Compared with other DL models, the proposed TFAFI-1DCNN-LSTM exhibits higher pre-stress identification accuracy, excellent noise-robustness, and superior performance under only a few trainable samples. The correlation between features extracted by the network and the pre-stress labels significantly increases with the deepening of the network, and the correlation between input UGW signals and predicted pre-stress values is effectively interpreted utilizing LIME, proving that the architecture of the proposed framework is reasonable and effective, the predicted results are reliable and credible.

Quantifying stress distribution in ultra-large graphene drums through mode shape imaging

Suspended drums made of 2D materials hold potential for sensing applications. However, the industrialization of these applications is hindered by significant device-to-device variations presumably caused by non-uniform stress distributions induced by the fabrication process. Here, we introduce a methodology to determine the stress distribution from their mechanical resonance frequencies and corresponding mode shapes as measured by a laser Doppler vibrometer (LDV). To avoid limitations posed by the optical resolution of the LDV, we leverage a manufacturing process to create ultra-large graphene drums with diameters of up to 1000 μm. We solve the inverse problem of a Föppl–von Kármán plate model by an iterative procedure to obtain the stress distribution within the drums from the experimental data. Our results show that the generally used uniform pre-tension assumption overestimates the pre-stress value, exceeding the averaged stress obtained by more than 47%. Moreover, it is found that the reconstructed stress distributions are bi-axial, which likely originates from the transfer process. The introduced methodology allows one to estimate the tension distribution in drum resonators from their mechanical response and thereby paves the way for linking the used fabrication processes to the resulting device performance.

Time-Limited Aging Analysis of the Containment of Nuclear Power Plants without Monitoring Tendons

A prestressed concrete containment is the enclosure structure of a nuclear reactor that serves as the last physical barrier of a nuclear power plant (NPP) safety defense system. It plays a key role in the prestress time-limited aging analysis (TLAA) required for operating license extensions for NPPs. Considering prestress containment systems without long-term monitoring tendons in a nuclear power plant, the technical route for prestress TLAAs involves analyzing operating license extension regulations and in-service monitoring technical requirements for prestressed tendons performance. Using tendons based on theoretical calculations of prestress loss in a nuclear power plant and the minimum required value of prestress determined by numerical simulation, the theoretical predictive value can be compared with the minimum required value for prestressed steel tendons. This comparison can be used to evaluate the 20-year life extension of the prestress system and provide a reference for aging and life management of NPPs.

On maintaining bistability of prestressed laminates after clamping

Bistable composite laminates exhibit a high degree of shape change and stiffness variation between their stable configurations, making them suitable for applications in morphing structures and energy harvesting. However, integration of these laminates into larger systems often imposes different boundary conditions, which can eliminate one of their stable states. Moreover, clamping one or more edges of a rectangular bistable laminate causes a drastic change in its strain energy landscape, indicating a strong interplay between the laminate geometry, boundary conditions, and prestress. In this work, we investigate the effect of clamping on the bistability of rectangular prestressed laminates. An analytical approach is proposed to examine the deflection decay imposed by the boundary condition along the laminate’s length. Different prestress values, laminate dimensions, and material properties are analyzed to establish their effect on the curvature change due to the localized clamp effect. A length criterion is determined to guarantee bistability after clamping the bistable laminate, suggesting the need to utilize complementary techniques to retain the bistable behavior for orthotropic prestressed laminates. Different strategies to counter the clamped edge effect and thereby retain the bistability of these types of laminates are then examined. The proposed analytical model is expanded to consider multi-section composite laminates, showing the role of the symmetric regions in bistability retention. Finally, the results from the model are validated against experiments.

Seismic performance evaluation of precast post-tensioned high-performance concrete frame beam-column joint under cyclic loading

Precast concrete structures have developed rapidly because they meet the requirements of green and low-carbon social development. In this paper, a precast post-tensioned high-performance concrete frame beam-column joint was proposed, and the low-cycle reversed load test was performed on the four proposed joints. The main differences between the four joints are the different prestress values applied by the joints and whether the beam-column joint is provided with L-shaped steel. The seismic performance indexes such as hysteresis curve, stiffness degradation, deformation capacity, energy dissipation capacity and residual deformation of each node were obtained through experiments. By comparing various seismic performance indicators, it could be found that the use of high-performance concrete could effectively avoid the phenomenon of local crushing of concrete due to excessive prestressing. At the same time, it was found that the setting of L-shaped steel plate at the beam-column junction could effectively avoid the early damage at the beam-column junction. On the basis of the test, the three-line restoring force model of the joint was established by the method of experimental regression analysis. The model could better reflect the stress situation of each stage of the joint. Based on the experimental and theoretical analysis, the finite element analysis model of the joint was established, and the model calculation results were in good agreement with the experimental results.

Study on the flexural properties of T-shaped concrete beams reinforced with iron-based shape memory alloy rebar

Iron-based shape memory alloys (Fe-SMAs), which are emerging as a novel class of self-prestressing materials dispensed with in situ tensioning, have been studied primarily in the field of structural strengthening. In addition, the self-prestressing characteristics of the Fe-SMA rebars are extremely promising for new concrete bridges that are seriously affected by prestress loss during their service life. Therefore, the effect of self-prestress generated by embedded Fe-SMA rebar was experimentally investigated by six concrete T-beam. The influence of factors such as the activation status, prestress value, and diameter of the Fe-SMA rebar on the flexural performance was investigated. The variation laws of the cracking load, yield load, ultimate load, and stiffness were analyzed. The results illustrated that the activation of the Fe-SMA rebar had a remarkable influence on delaying beam cracking. Under the same load (130 kN), the specimens with an activated Fe-SMA rebar exhibited a remarkable reduction exceed 30% in crack width compared to those with an unactivated Fe-SMA rebar. Following the activation, the cracking load, yield load, ultimate load, and stiffness increased to varying extents,. The Fe-SMA, characterized by its remarkable ductility, exerted a beneficial influence on the deformation capability of the beams. This enhancement became notably conspicuous following Fe-SMA activation. Analysis of the cracking load and concrete strain during the activation process indicated that the prestress of the embedded Fe-SMA rebar closely approximated the values observed in the rigid confinement. The calculated flexural capacity agreed with the experimental data, and the proposed calculation method can provide a reference for subsequent research.

Tensile strength based two-phase fatigue process prediction model of prestressed UHPC beams

A fatigue process prediction model of prestressed UHPC beams was established leveraging the tensile strength contribution of UHPC; based on the stress analysis of the UHPC beam, the fatigue process was divided into two phases: uncracked and cracked. The calculation results of the model were compared with the test results in other literatures, and the applicability of the model was verified. A railway prestressed UHPC box girder was taken as an example, and the effects of UHPC strength, prestress value, stress amplitude, reinforcement ratio, and span on the fatigue properties were investigated. The results verified the availability of the fatigue process prediction model of the prestressed UHPC beam; the error of UHPC strain and mid-span deflection development during the fatigue process is within 7%. The investigation of parameters showed that the prestress value, stress amplitude, and span have a great influence on fatigue life, while UHPC strength has a minor impact. At the early stage of the fatigue process, UHPC strength has a massive influence on the growth of strain, while other factors have almost no effect. At the later stage of the fatigue process, the prestress value, stress amplitude, and span have a significant impact on the growth of strain.

Review and analysis of RC bridge half-joints strengthening techniques

In the past, the extensive use of the Gerber scheme in the construction of existing bridges has been justified by the advantages in terms of reduced stresses of the statically determined scheme and rapid execution. On the other hand, the presence of junction elements at the ends of the beams has over time led to a series of issues, especially related to their durability. In fact, the half-joints’ geometric configuration leads to the accumulation of degradation due to platform water seepage, resulting in the initiation of reinforcement corrosion, especially in the presence of chlorides derived from de-icing salts used in the winter season. Furthermore, these elements have been designed for lower loads than those specified in current regulations, and therefore, they may be in critical conditions where the strength reduction, due to existing degradation, can lead to failure. For these reasons, local repairs and/or strengthening interventions are necessary to ensure adequate levels of safety. Within this study, the topic of reinforcing half-joints is addressed, first by describing the currently available intervention techniques in the literature, and then by deepening an intervention technique based on the use of external post-tensioned bars, applied to a case study bridge through nonlinear numerical simulations. These analyses allow quantifying the performance improvements of this technique under both service conditions and ultimate loads, considering various parameters, including the pre-stress value applied to the external tendons and different scenarios of chloride-induced corrosion.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

Abstract 13988: Post Stress Test High-Sensitivity Cardiac Troponin I in the Evaluation of Patients With Acute Chest Pain for Enhanced Ischemic Risk Assessment: A Pilot Study

Introduction: High-sensitivity cardiac troponin I (hs-cTnI) assays provide comparable diagnostic information that allow for better detection of myocardial injury. However, hs-cTnI release after cardiac stress testing and its potential utility for identifying inducible myocardial ischemia and risk-stratification are unclear. Aim: This pilot study examined integrating hs-cTnI biomarker testing into cardiac imaging stress testing to improve detection of inducible ischemia and aid in risk-stratification in patients with chest pain being evaluated for acute coronary syndrome (ACS). Methods: We prospectively enrolled 200 consecutive adult patients referred by the Emergency Room for cardiac stress testing for evaluation of possible ACS. A venous blood sample was collected between 0.5 and 2 hours post stress testing; cTnI concentrations were measured in-house by high sensitivity methods. Changes from pre-stress test hs-cTnI concentrations were calculated and association with outcome was explored using a logistic regression model. Results: Patient median age was 62 years, IQR 54-70; 49% were women. ACS known risk factors included hypertension 81.5%, cigarette smoking 49.5% and diabetes 33.5%. Median BMI was 31.63 kg/m 2 , IQR 27.24-35.84. Pre-stress test hs-cTnI median levels were 6 ng/L, IQR 5-9, for women (URL <52 ng/L) and 8 ng/L, IQR 6-12, for men (URL <77 ng/L). A total of 121 patients (60.5%) underwent nuclear stress tests, and 79 (39.5%) received echocardiographic stress tests. Of the 191 samples analyzed, 36% revealed increased hs-cTnI levels from pre-stress test values: 33% in nuclear stress tests (median increase 2 ng/L, IQR 1-5), 41% in echocardiographic stress tests (median increase 2 ng/L, IQR 1-5). In the 155 patients with 6 months of follow-up, changes in post-stress test hs-cTnI levels were not significantly correlated to stress test results, percutaneous coronary interventions or death (p=.85). Conclusion: This study provides insight into the potential of hs-cTnI to aid in identifying inducible myocardial ischemia in a real-world, high-throughput setting. Although a subset of patients exhibited modest increases in hs-cTnI post stress testing, overall, these did not appear to be correlated with inducible myocardial ischemia.

Buckling Analysis of a New Type of Double-Steering Prestressed Plate Column

A new type of dual-steering prestressed plate column is introduced. Compared to the previous prestressed strut column, this proposed column considers both bending and constraints at ends. The calculation results indicated that the support plate significantly improves the stable bearing capacity and buckling performance of the core steel column. When compared to the proposed column, the bearing capacity of the three-transverse prestressed beam column is 1.51 times smaller, the single-transverse prestressed beam column is 2.43 times lower, and the non-prestressed column is 4.51 times smaller. Moreover, this study examines the influences of effective length, buckling mode, stress nephogram detail, and prestress value. It explores the possibility of implementing this new type of dual-steering prestressed plate column in practical engineering. In addition, the variety and mechanical models of prestressed columns are expanded and refined.

Tensegrity triboelectric nanogenerator for broadband blue energy harvesting in all-sea areas

The integration of high-density friction layer units is a promising approach for achieving high output in triboelectric nanogenerators (TENGs). Yet, the synchronization and sufficient contact separation of these high-density layer units are inherently challenging due to the cumulative impact of gravity. Herein, a tensegrity structure was applied and effectively organized the high-density stacked TENG units into an ordered whole, thereby proposing the T-TENG. Along with achieving orderly contact and separation of high-density friction layers, the T-TENG effectively reduced the device's height (up to 52%) and improved the friction layer surface area density (up to 1.07 cm−1). Significantly, the built-in prestress modulation not only enhances the device's load-bearing capacity but also enables ease in changing the T-TENG's response frequency by adjusting the prestress value. This is especially suitable for efficiently capturing omnidirectional wave energy in all-sea areas with frequency variations. The working mechanism and output influencing parameters of T-TENG were systematically expounded, and it demonstrated a maximum output voltage of up to 1020 V and output charge per unit time of 0.816 mC/min, sufficient to light up to 1512 LEDs directly. Moreover, customization of low-loss gas discharge tubes to amplify outputs allows T-TENG to harvest wave energy for power supply to small electronic devices such as water quality testing pens and Bluetooth modules when placed over water bodies. This work provides a foundational model to develop high-density friction layers and high-output TENGs.

Enhancing the surface integrity and SCC resistance of 304 austenitic stainless steel by pre-stress grinding

In order to improve the surface integrity and enhance stress corrosion crack (SCC) resistance of stainless steel (SS) materials, this study investigates the application of pre-stress grinding (PG) technique. The impact of PG on various surface integrity parameters, including residual stress, surface topography, surface roughness, and microstructure, is examined. Additionally, the SCC behavior of the ground surface is evaluated and compared under different levels of pre-stress applied during PG. Experimental results demonstrate that the integrity of the PG-treated surface is significantly improved, leading to enhanced SCC resistance. This enhancement can be attributed to the additional compression effect generated by the applied pre-stress, as well as the increased surface rigidity of the material. Furthermore, numerical analyses indicate higher temperatures and lower plastic strain rates during PG, which effectively inhibit the martensitic phase transformation. However, it is important to note that the strengthening effect of pre-stress may have an upper limit, thus higher pre-stress values are not necessarily more advantageous, and it is crucial to ensure that the applied stress does not exceed the yield strength of the material. Additionally, achieving an ultrafine-grained surface requires the implementation of more aggressive grinding parameters.

Interactive effects of culture systems (biofloc and clear water) and dietary protein levels on growth, digestive activity, mucosal immune responses, antioxidant status, and resistance against salinity stress in the Caspian roach (Rutilus caspicus) fry

This experiment aimed to evaluate effects of culture system and dietary protein level on performance of the Caspian roach fry. Fish (0.99 ± 0.06 g) were stocked into 12 tanks (water volume, 50 L) at a stocking density of 100 fish per tank. The experiment was designed with two culture systems (biofloc, BFT and clear water, CW) each with 38 and 28% dietary protein levels following a 2 × 2 factorial design. After 60 days, fifty fish were randomly captured from each tank and exposed to salinity challenge (13 g/L) for 72 h. On days 45 and 60, total ammonia nitrogen (TAN) values were significantly higher in CW treatments, then BFT38 treatment, and lower in BFT28 treatment. The final weight, weight gain, and SGR in BFT and CW38 treatments were significantly higher and FCR was lower than the CW28 treatment. The protein efficiency ratio was highest in the BFT28 treatment. Also, amylase, lipase, and protease activities in fish cultured in BFT system were significantly higher than the CW system. After salinity stress, skin mucus cortisol values were significantly lower and survival rate was higher in BFT groups compared to the CW treatments. After 72 h stress, the mucus glucose values in BFT and CW38 treatments were significantly lower than the CW28 treatment. Before stress, the mucus alkaline phosphatase (ALP) activity was lowest in the CW28 treatment. Skin mucus protease activity was significantly higher in BFT groups at before and all sampling times after salinity challenge. The skin mucus lysozyme activity and total protein value in all treatments increased at 24 h post stress, and then only returned to the pre-stress values at 48 h for the BFT38 treatment. After salinity stress, lysozyme activity in BFT and CW38 treatments was significantly lower than the CW28 treatment. After 48 h stress, the highest mucus ACH50 activity was observed in the BFT38 treatment, but it was not significantly different from the BFT28 and CW38 treatments. After salinity stress, muscle catalase and SOD activities were significantly higher and MDA content was lower in BFT treatments than the CW treatments, suggesting that biofloc can enhance the antioxidant defense in fish. Overall, biofloc system and high dietary protein level beneficially affect growth, skin mucus immune responses, and resistance against salinity challenge in fish. Also, microbial proteins contained in bioflocs as a supplemental protein source can compensate 10% reduction of protein in the Caspian roach fry diet.

Experimental Study on Prestressed CFRP-reinforced Aluminum Alloy Bridge Panel Based on Shape Memory Alloys

In order to strengthen aluminum alloy bridge panels, a CFRP (Carbon Fibre Reinforced Plastics) plate is tensioned under the bottom plate to exert prestress. Installing the tensioning device under narrow bottom plates of bridge panels via traditional prestressing method is difficult; therefore, a new prestress tensioning technology based on Shape Memory Alloy (SMA) is employed to efficiently apply the prestress. The tensioning and anchorage device used in prestressing technology has been designed and manufactured. A tensile stress of 360Mpa was applied to the CFRP plate with the tensioning and anchorage device and then, load-bearing tests were performed on prestressed reinforced aluminum alloy and unreinforced bridge panels, respectively. Experimental results showed that the proposed CFRP prestressing technology was feasible and verified the application possibility of SMA as a prestress device in practical engineering. The new technology ensured that the desired prestress value was applied to aluminum alloy bridge panel and the strength and stiffness of aluminum alloy bridge panels reinforced with the proposed technology were significantly improved.

Influence of flange geometric configuration and bolt stress on joint integrity during assembly using FEA

The aim of this study is to develop a procedure suitable to determine the maximum bolt pre-stress required for the proper gasket seating in bolted flange connections. The proposed method is valid for all the flange types and assumes that the gasket leakage must be limited so as to not affect the flange joint integrity. A 3D finite element model is used in which elastic–plastic behaviour of the flange material, non-linear gasket material behaviour and non-linear flange–gasket contact are assumed. The final goal of the developed work is to update, using a more realistic perspective, the recommendations given by ASME PCC-1 Appendix-O for bolt pre-stress values when applied to standard dimensional ASME flanges. Additionally, in this work, the effect of the straight portion length of the flange hub at its welded connection with the connected pipe and the fillet radius at the hub-flange transition on the stresses and strains distribution are also addressed.

Оптимальное проектирование большепролетной арочной конструкции

Introduction. Large-span structures are designed as entertainment and mass-use buildings, sports facilities, etc. A steel arched structure can be used as a covering for large-span structures. The issue of the rational design of large-span steel arches, as well as the proper choice of the structural design and the analysis of its bearing capacity is relevant. Materials and methods. The covering of a tennis sports facility with the span of 108 m, that represents a double-hinged steel arch without tightening, arches with prestressed tightening and several lattice options are considered. The cross-section of structural elements was selected; the effect of prestressing on forces and displacements in the arch, as well as the amount of metal per structure were analyzed. The general stability of these arched structures was analyzed. Calculations were performed in the geometrically nonlinear formulation using the LIRA-SAPR software package. Results. It is determined that the weight of the arch, including the tightening and the lattice is smaller than the weight of the arch without the tightening. The amount of metal, used to make columns, can be reduced to simplify structural units due to the absence of gusset transfer from the arch with tightening to columns. The required prestressing value is set for the tightening to ensure the required rigidity of the arch. Several methods were used to determine the critical load at which the arch loses its stability in its plane: the analytical method, geometrically nonlinear calculation results, and the Stability mode implemented in LIRA-SAPR software package were employed. The critical load turned out to be higher for the arch with tightening. Conclusions. Following the above computations, a decision was made to use a double-hinged arch with prestressed tightening and a lattice as the covering of the sports facility. The values of the critical load that triggers the arch stability loss, obtained using the geometrical nonlinear finite-element analysis and the Stability mode, were quite close. Application of the analytical method resulted in an overestimated value of the critical load, which prevents it from being recommended for use.

Yoga versus classical dance therapy to reduce stress in women working from home

Background: COVID-19 pandemic led to rise of work from home job pattern. Although, now the situation is better still the hybrid pattern of work continues. This situation has led to rise in stress levels in women working from home. Early intervention to reduce the stress will help to overcome ill effects of stress like headache, sleep disturbances, mental health issues, hypertension etc. This study aims to understand which intervention works the best to reduce stress in women working from home.Methods: Yoga as an intervention which had sustained posture and breathing control techniques while classical dance therapy-Bharatnatyam had structured basic dance movements and portraying of nine emotions. Pre and post intervention stress values were assessed through an outcome measure-the perceived stress scale-10. Online intervention for thrice a week for four weeks was incorporated.Results: The results interpreted that post four week of intervention through online mode yoga therapy gives statistically and clinically significant decrease in stress levels while classical dance therapy gives clinically significant result but fails to give statistically significant result.Conclusions: Women working from home mostly had moderate stress on perceived stress scale 10. Yoga therapy reduced the stress post four weeks in women working from home. The reduction in stress was statistically significant. Classical dance therapy reduced the stress post four weeks in women working from home. But, the reduction in stress was not statistically significant. Yoga is better than classical dance to reduce stress in women working from home.

Degradation Behavior and Mechanism of SiC Power MOSFETs Under Repetitive Transmission Line Pulse Stress

The electrostatic discharge robustness of silicon carbide (SiC) power metal–oxide–semiconductor field-effect transistors (MOSFETs) are investigated by the transmission line pulse (TLP) method. The degradation behavior of key electrical parameters of the device under repetitive TLP stress is investigated. A decrease in threshold voltage, an increase in gate leakage current, and the degradation of gate capacitance parameters are observed compared with the prestress values. Low-frequency noise (LFN) test results show that after multiple TLP stress cycles, the typical leakage current noise of the device increases by approximately one order of magnitude compared to prestress, which means that the trap density extracted based on the McWhorter model increases by one order of magnitude after 1000 TLP stress pulses. Furthermore, sources of defects in the gate oxide dielectric of the devices after stresses are analyzed. The physical mechanism of the changes of SiC MOSFETs characteristics could be attributed to the hole trapping by oxygen vacancy defects and single carbon interstitial in the oxide layer after TLP stresses, which induces an electrostatic effect and results in the changes in the electrical properties of the devices. The results may be useful in the design and application of SiC power MOSFETs.