Triple Error Research Articles

Study on fatigue properties with composite waveform and variable amplitude of TC21 titanium alloy pulsed laser-arc hybrid welded joints

TC21 titanium alloy is widely used in the manufacturing of key components such as aerospace industry, its welded structure in actual service is often subjected to the cyclic loading with composite waveform and variable amplitude and leads to fatigue failure. Therefore, in this work, the composite waveform and variable amplitude fatigue properties of TC21 titanium alloy pulsed laser-arc hybrid welded joints were investigated in this paper, and the micro-deformation mechanism and crack initiation mechanism of welded joints under different initial maximum cyclic stresses were revealed. The results indicated that the micro-deformation mechanism was the competition between twinning and dislocation slip in the α′ phase at low stress. When the initial maximum cyclic stress increased, the generation and slip of dislocation dominated, and the main distribution of dislocations gradually transitioned from the α′ phase to the β phase. This caused the phase transition in the β phase to the α phase, which increased the energy at the α/β phase interface and reduced the resistance of fatigue microcrack initiation accordingly, thus promoting fatigue failure. In addition, pores were the main factor of fatigue failure for welded joints. Therefore, in this work, the influence of defect size, location and shape on the fatigue life of welded joints was considered to develop a fatigue life prediction model based on the control parameter Z-parameter and equivalent stress amplitude. The predicted composite waveform and variable amplitude fatigue life of TC21 titanium alloy welded joints was within the triple error band.

Heterogeneous Views and Spatial Structure Enhancement for triple error detection

Knowledge graph error detection is to identify erroneous triples in knowledge graphs that are inconsistent with objective facts in the real world. In practice, the quality of knowledge graphs is an indispensable foundation for the widespread and accurate knowledge application services such as intelligent retrieval and human machine dialogue. Technically, the existing knowledge graph error detection methods face the following two problems: few available negative samples of triples, and an uneven data distribution. That distribution is caused by the large disparity in the number of head and tail entities belonging to the same relationship and the disparity in the number of triples with different relationships. To alleviate these problems, this paper proposes an approach based on the Heterogeneous Views and Spatial Structure Enhancement (HVSSE) in a contrastive learning framework for triple error detection task. Specifically, the heterogeneous views are constructed to include four kinds of triple views, i.e., positive and negative triple views based on head or tail entity co-occurrence. Moreover, Graph-Spatial-Transformer with an explicit spatial structure encoding is designed to fully capture the contextual information of triple nodes. Thereby, driven by the framework of contrastive learning, our HVSSE model can not only learn more discriminative embedding of triples, but also capture the local structure of triples and global contextual information of knowledge graphs. Experimental results on five public datasets indicate that our proposed approach is superior to the state-of-the-art methods, showing its the effectiveness on triple error detection.

Fatigue performance testing and life prediction of welded fuel pipes

The external piping system which connects power devices, valve control devices, actuators, etc. is an essential system on the aero engine. Under the combined effects of high fluid pressure and external vibration, multiaxial fatigue failure is the main factor that seriously affects the safety of the piping system. The objective of this paper is to establish the multiaxial fatigue life model for the typical welded fuel pipe of the piping system by combining fatigue testing, simulation and theoretical analysis which is of great guiding significance for the engineering application of the piping system. Firstly, the fatigue limits of welded fuel pipes under no and 13.5 MPa internal pressure are obtained by rotational bending fatigue tests using the up-and-down method. Three additional stress levels of rotational bending fatigue tests under no internal pressure are supplemented and then the S-N curve is further obtained by the group method. Since the corresponding fracture surface of the specimens locates at the weld toe near the fixed end, peak stress method is adopted to evaluate the fatigue performance of the weld toe on the pipe specimens. In addition, by comparing the fatigue limit with no and 13.5 MPa internal pressured pipes, it is obvious that the equivalent uniaxial stress corrected by Gerber formula is not applicable for the multiaxial fatigue condition which is caused by the combined effect of fluid pressure and displacement load. The local stress concentration factor caused by the weld toe is determined and based on Findley critical plane model, the multiaxial fatigue life model is established which simultaneously takes the local stress concentration effect, mean stress effect and multiaxial stress effect into consideration. The results of rotational bending fatigue tests under 13.5 MPa internal pressure are within the triple error dispersion band and the accuracy of the proposed life model are verified.

Study on fatigue damage and frequency attenuation characteristics of carbon fiber composite

Fatigue analysis and life prediction are the key and challenging issues in the mechanics research of composite material. In this paper, based on the progressive damage analysis method and fatigue cumulative damage theory, a three-dimensional fatigue cumulative damage numerical model is constructed by introducing the orthotropic constitutive equation, 3D-Hashin fatigue criterion, and material performance degradation scheme. Two loading conditions of tension–tension fatigue and compression–compression fatigue of Carbon Fiber composite laminates were investigated. In the tension–tension fatigue experiments, when the cycle is [Formula: see text] times, the experiment and the numerical simulation all not completely destroyed. However, progressive degradation of stiffness and strength was observed in certain elements, accompanied by some internal damage. On the other hand, the experimental and predicted values for compression–compression fatigue were within a triple error band. Then the cumulative damage evolution law of each laminate under fatigue load was analyzed. Compression–compression fatigue damage initiated from the center of the hole and expanded to both sides of the composite laminate, and its fatigue life increased with the increase of the compression–compression fatigue load. Considering the degradation of stiffness in composite materials under fatigue loading, which leads to frequency attenuation in the structure, this paper established a connection between the fatigue state and frequency to obtain the frequency attenuation curve under fatigue loading. The relationship between frequency and fatigue life was revealed, allowing for the prediction of remaining fatigue life in practical engineering based on the rate of inherent frequency reduction.

An ML-Based Approach for HCF Life Prediction of Additively Manufactured AlSi10Mg Considering the Effects of Powder Size and Fatigue Damage

As a popular technique, additive manufacturing (AM) has garnered extensive utilization in various engineering domains. Given that numerous AM metal components are exposed to fatigue loads, it is of significant importance to investigate the life prediction methodology. This study aims to investigate the high-cycle fatigue (HCF) behavior of AM AlSi10Mg, taking into account the influences of powder size and fatigue damage, and a novel ML-based approach for life prediction is presented. First, the damage-coupled constitutive model and fatigue damage model are derived, and the Particle Swarm Optimization method is employed for the material parameters’ calibration of M AlSi10Mg. Second, the numerical implementation of theoretical models is carried out via the development of a user-defined material subroutine. The predicted fatigue lives of AM AlSi10Mg with varying powder sizes fall within the triple error band, which verifies the numerical method and the calibrated material parameters. After that, the machine learning approach for HCF life prediction is presented, and the Random Forest (RF) and K-Nearest Neighbor (KNN) models are employed to predict the fatigue lives of AM AlSi10Mg. The RF model achieves a smaller MSE and a larger R2 value compared to the KNN model, signifying its superior performance in predicting the overall behavior of AM AlSi10Mg. Under the same maximum stress, a decrease in the stress ratio from 0.5 to −1 leads to a reduction in fatigue life for both powder sizes. As the powder size decreases, the rate of damage evolution accelerates, leading to shorter fatigue life.

Ultra-High-Cycle Fatigue Life Prediction of Metallic Materials Based on Machine Learning

The fatigue life evaluation of metallic materials plays an important role in ensuring the safety and long service life of metal structures. To further improve the accuracy and efficiency of the ultra-high-cycle fatigue life prediction of metallic materials, a new prediction method using machine learning was proposed. The training database contained the ultra-high-cycle fatigue life of different metallic materials obtained from fatigue tests, and two fatigue life prediction models were constructed based on the gradient boosting (GB) and random forest (RF) algorithms. The mean square error and the coefficient of determination were applied to evaluate the performance of the two models, and their advantages and application scenarios were also discussed. The ultra-high-cycle fatigue life of GCr15 bearing steel was predicted by the constructed models. It was found that only one datapoint of the GB model exceeded the triple error band, and the RF model had higher stability. The network model coefficient of determination and mean square error for the GB and RF models were 0.78, 0.79 and 0.69, 3.79, respectively. Both models could predict the ultra-high-cycle fatigue life of metallic materials quickly and effectively.

A predicting model for three-dimensional crack growth in power-law creeping solids

Creep fracture mechanics has been extensively studied in the past half a century, but the gap between the creep crack-tip asymptotic field and crack growth prediction has not been effectively bridged so far, hindering the development of high temperature damage tolerance design. Here a predicting model is developed for three-dimensional crack growth in power-law creeping solids with the C(t)PC-Tz asymptotic solution being applied to quantify the creep crack growth driving force. The local resistance for creep crack growth in three-dimensional cracked structures is then described and evaluated based on the micro-cavity growth and constraint theories. Validation against forty-four crack growth experimental data for eleven creeping materials with deferent properties and specimen geometries and subjected to different load level in the literature shows that the proposed model can effectively predict the creep crack growth rate and provide the upper and lower limits. In all cases, the predicted crack growth life is within a triple error band around the experimental data. All the needed material parameters can be obtained from tension tests of standard uniaxial round bar specimens. Therefore, the proposed model can bridge the C(t)PC-Tz asymptotic solution with creep crack growth in practical materials and specimens, paving a road to predict damage tolerance of three-dimensional cracked structures at high temperature.

Error Detection and Correction for Golay Code & Extended Golay Code using Cyclic Redundancy Check

In this paper certain optimization techniques are proposed to reduce the encoder and decoder computation time of cache memory that is affected by soft error and by implementing ECC such as cyclic and block codes. Error that is adjacent by a width of three and two bits are the prime concern of this thesis. Optimised Golay code (23, 12) and new block code size (32, 19) which is also optimised are presented. Nevertheless, cyclic code is efficient compared with block code however, the prime concern of the thesis is to address the triple and double adjacent errors which also includes single bit error, in this regard built-in capability of Golay code is optimised and used for comparison. The extended Golay code is implemented in term of number of slice, number of LUT and maximum combinational path delay compared with existing Golay code.

Effective extraction method for triple errors in foreground calibration of TI‐ADCs

AbstractThis paper presents a novel procedure for detecting offset, gain, and timing skew errors in foreground calibration of time‐interleaved analog‐to‐digital converters (TI‐ADCs). An efficient peak detection scheme has been introduced, which is successfully employed to extract timing skew error. The designed method has also been extended to derive the gain and offset errors separately to form the generalized architecture. The objective is performed with the adjustment of the rational coefficient for each error. Simplicity and low hardware consumption will constitute the notable advantages of the proposed algorithm. Mathematical expressions have been provided to explain the principles. A special case in which all triple errors could exist together has also been analyzed. Then, the proposed architecture was implemented at the system level. Finally, the behavioral simulation results for a 12‐bit four‐channel TI‐ADC have been demonstrated to confirm the accuracy of the proposed algorithm. The simulation environment has consisted of the sampling frequency of 8 GHz for TI‐ADC and 1 GHz single‐tone input frequency for each channel (associated with the Gaussian noise). Based on the results, the maximum value of 77.21 dB for SFDR has been achieved after the calibration process when the average error of 9% for timing skew and 6% tolerance for gain were considered for the channels of TI‐ADC.

СИНТЕЗ ПОЛНОСТЬЮ САМОПРОВЕРЯЕМЫХ СХЕМ ВСТРОЕННОГО КОНТРОЛЯ НА ОСНОВЕ ПОЛИНОМИАЛЬНЫХ КОДОВ ДЛЯ КОМБИНАЦИОННЫХ ЛОГИЧЕСКИХ УСТРОЙСТВ

The article examines the methods of production of functional control systems for logic combinational circuits with full detection of any single faults using the error detection properties of polynomial codes. A classification of special generators of polynomials that form codes with a small value of the control vector length and complete identification of errors of a certain type or multiplicity is presented. A method is presented for constructing a functional control system with complete identification of single faults based on the complete detection of triple errors by polynomial codes. Algorithms for the search and formation of controllable H1-, H2- and H3-groups of circuit outputs, taking into account the properties of polynomial codes, have been developed. The types of functional dependence of the operating outputs for combinational circuits are listed, in which errors of various types can occur. Based on the detection of any symmetric and asymmetric errors by polynomial codes, a method is presented for the constructionof functional control systems with full identification of these type of errors. For an approximate scheme, the development of a functional control system based on the proposed methods is given as:-

Reduced complexity hard‐ and soft‐input BCH decoding with applications in concatenated codes

Error correction coding for optical communication and storage requires high rate codes that enable high data throughput and low residual errors. Recently, different concatenated coding schemes were proposed that are based on binary BCH codes with low error correcting capabilities. In this work, low-complexity hard- and soft-input decoding methods for such codes are investigated. We propose three concepts to reduce the complexity of the decoder. For the algebraic decoding we demonstrate that Peterson's algorithm can be more efficient than the Berlekamp–Massey algorithm for single, double, and triple error correcting BCH codes. We propose an inversion-less version of Peterson's algorithm and a corresponding decoding architecture. Furthermore, we propose a decoding approach that combines algebraic hard-input decoding with soft-input bit-flipping decoding. An acceptance criterion is utilised to determine the reliability of the estimated codewords. For many received codewords the stopping criterion indicates that the hard-decoding result is sufficiently reliable, and the costly soft-input decoding can be omitted. To reduce the memory size for the soft-values, we propose a bit-flipping decoder that stores only the positions and soft values of a small number of code symbols. This method significantly reduces the memory requirements and has little adverse effect on the decoding performance.

Fault Injection Emulation for Systems in FPGAs: Tools, Techniques and Methodology, a Tutorial.

Communication systems that work in jeopardized environments such as space are affected by soft errors that can cause malfunctions in the behavior of the circuits such as, for example, single event upsets (SEUs) or multiple bit upsets (MBUs). In order to avoid this erroneous functioning, this kind of systems are usually protected using redundant logic such as triple modular redundancy (TMR) or error correction codes (ECCs). After the implementation of the protected modules, the communication modules must be tested to assess the achieved reliability. These tests could be driven into accelerator facilities through ionization processes or they can be performed using fault injection tools based on software simulation such as the SEUs simulation tool (SST), or based on field-programmable gate array (FPGA) emulation like the one described in this work. In this paper, a tutorial for the setup of a fault injection emulation platform based on the Xilinx soft error mitigation (SEM) intellectual property (IP) controller is depicted step by step, showing a complete cycle. To illustrate this procedure, an online repository with a complete project and a step-by-step guide is provided, using as device under test a classical communication component such as a finite impulse response (FIR) filter. Finally, the integration of the automatic configuration memory error-injection (ACME) tool to speed up the fault injection process is explained in detail at the end of the paper.

Reliability Analysis of Multibit Error Correcting Coding and Comparison to Hamming Product Code for On-Chip Interconnect

Error control schemes became a necessity in network-on-chip (NoC) to improve reliability as the on-chip interconnect errors increase with the continuous shrinking of geometry. Accordingly, many researchers are trying to present multi-bit error correction coding schemes that perform a high error correction capability with the simplest design possible to minimize area and power consumption. A recent work, Multi-bit Error Correcting Coding with Reduced Link Bandwidth (MECCRLB), showed a huge reduction in area and power consumption compared to a well-known scheme, namely, Hamming product code (HPC) with Type-II HARQ. Moreover, the authors showed that the proposed scheme can correct 11 random errors which is considered a high number of errors to be corrected by any scheme used in NoC. The high correction capability with moderate number of check bits along with the reduction in power and area requires further investigation in the accuracy of the reliability model. In this paper, reliability analysis is performed by modeling the residual error probability Presidual which represents the probability of decoder error or failure. New model to estimate Presidual of MECCRLB is derived, validated against simulation, and compared to HPC to assess the capability of MECCRLB. The results show that HPC outperforms MECCRLB from reliability perspective. The former corrects all single and double errors, and fails in 5.18% cases of the triple errors, whereas the latter is found to correct all single errors but fails in 32.5% of double errors and 38.97% of triple errors.

Generalized Method for Extraction of Offset, Gain, and Timing Skew Errors in Time-Interleaved ADCs

In this brief, a novel scheme for the derivation of triple errors associated with Time-Interleaved Analog-to-Digital Converters (TI-ADCs) has been presented. This algorithm relies on the utilization of reference Analog-to-Digital Converter (ADC) for the background calibration process. The main advantage of the proposed architecture is that it provides the possibility to calibrate offset, gain and timing skew by utilization of a simple structure. The objective has been accomplished by adjusting the corresponding coefficients of each error. At first, the main idea has been introduced by mathematical expressions. Then, the architecture for extraction of each error has been derived from the calculations, and the generalized scheme has been demonstrated which extracts the errors. Finally, system-level simulations were provided to indicate the correct behavior of the proposed algorithm for a 12-bit 4-channel TI-ADC. Based on simulation results, the maximum value of 81dB for SFDR after calibration process has been achieved when an average error of 11ps was considered for each channel at the sampling frequency of 8GHz and 1GHz single tone input frequency. Also, the corresponding maximum value for SNDR is 66dB.

Properties of triple error orbits G and their invariants in Bose – Chaudhuri – Hocquenghem codes C7

This work is the further development of the theory of norms of syndromes: the theory of polynomial invariants of G-orbits of errors expands with the group G of automorphisms of binary cyclic BCH codes obtained by joining the degrees of cyclotomic permutation to the group Γ and practically exhausting the group of automorphisms of BCH codes. It is determined that polynomial invariants, like the norms of syndromes, have a scalar character and are one-to-one characteristics of their orbits for BCH codes with a constructive distance of five. The paper introduces the corresponding vector polynomial invariants for primitive cyclic BCH codes with a constructive distance of seven, next to the norms of the syndromes that are already vector quantities; the basic properties of the vector polynomial invariants are investigated. It is established that the property of mutual unambiguity is violated: there are G-orbit-isomers, which are different, but have the same vector polynomial invariants. It is substantiated and demonstrated by examples that this circumstance greatly complicates error decoding algorithms based on polynomial invariants

Torsional whole-life transformation ratchetting under pure-torsional and non-proportional multiaxial cyclic loadings of NiTi SMA at human-body temperature: Experimental observations and life-prediction model

Torsional whole-life transformation ratchetting is investigated under pure-torsional and non-proportional multiaxial loadings of NiTi SMA micro-tubes at human-body temperature (310 K), where three paths of torsional loadings and five paths of multiaxial ones are considered. It is observed that the evolution of the torsional whole-life transformation ratchetting depends strongly on the loading paths and stress levels, and the fatigue lives of pure-torsional loadings decrease faster than that of uniaxial and multiaxial ones with the increase of peak stress. Based on the experimental investigations, a life-prediction model which depends on the applied stress levels is proposed for NiTi SMA micro-tubes, where the martensite transformation and reorientation of NiTi SMAs are considered. The predicted fatigue lives under uniaxial, torsional and non-proportional multiaxial loadings are mostly located within the triple error band.

Triple Probe Error Evaluation Caused by Spatial Separation in the HL-2A Tokamak

The systematic error between the measured electron temperature $T_{e,m}$ and the real electron temperature $T_{e}$ caused by the spatial separation of a triple probe is introduced. The detailed analysis of the systematic error is presented and the relation between $T_{e,m}$ and $T_{e}$ is derived. By comparing the fluctuation of the measured temperature $| \tilde {T}_{e,m}|$ and the real temperature fluctuation $| \tilde {T}_{e}|$ , we find that $| \tilde {T}_{e,m} |\ge | \tilde {T}_{e}|$ . In addition, electron temperature $T_{e}$ , density $n_{e}$ , floating potential $V_{f}$ , and their fluctuation profiles are measured at the edge of HL-2A tokamak with a reciprocating probe system. We experimentally verified that the amplitude of floating potential fluctuation $| \tilde {V}_{f} |$ is about 3 ~ 4 times larger than that of $\boldsymbol {\alpha }| \tilde {T}_{e,m} |$ ; in this condition, we can use the floating potential fluctuation $\tilde {V}_{f}$ to stand for the plasma potential fluctuation $\tilde {V}_{p}$ .

Design of Low-Complexity Decoder for Triple Error Correcting BCH Codes

Design of Low-Complexity Decoder for Triple Error Correcting BCH Codes

Reducing the Power Consumption of Fault Tolerant Registers Through Hybrid Protection

Soft errors produced by radiation events can cause malfunctions in modern day electronics. To preserve the system functionality, its elements must be protected against the effects of these events. Two of the possible techniques usually employed to implement fault tolerant registers are triple modular redundancy (TMR) and single error correcting (SEC) codes. However, the use of these techniques increases circuit area, timing, and power consumption to different extents. In this paper, we study the influence of each of these approaches on the circuit when they are implemented in application-specific integrated circuits and, based on the results, present some guidelines to choose between both of them depending on the design requirements. Additionally, we present a new low power fault tolerant technique destined for registers in which a subset of bits have a lower switching activity than the rest. This approach is based on the idea of combining TMR and SEC codes within a register to implement a hybrid protection that can exploit the strengths of each of the techniques. Our results show that the use of this technique achieves both power and area savings with respect to TMR in most cases, whereas it achieves large power savings with respect to SEC codes at the cost of increasing the area overhead.

Low Complexity Syndrome-Based Decoding Algorithm Applied to Block Turbo Codes

This paper presents a technique for reducing the decoding complexity of block turbo code with an extended Hamming code as a component code. In conventional decoding algorithms, when an input vector has a zero syndrome, complexity can be reduced by using the hard-input soft-output (HISO) algorithm. Although sufficient error correction can be achieved using hard decision decoding (HDD) of a component code, conventional methods have used the soft-input soft-output (SISO) algorithm for input vectors with a single error. However, when HDD is applied to all input vectors in which the syndrome is detected as a single error, performance loss occurs owing to the occasional presence of input vectors with triple errors. To solve this problem, we used two criteria for distinguishing between instances of single and triple errors. We maximized the applied rates of the HDD-based HISO algorithm depending on whether the criteria were satisfied. The SISO algorithm was applied when the two criteria were not met. In this case, the number of HDD usages can be reduced to half by removing duplicates or unnecessary candidate codewords. Simulation results show that the proposed algorithm can considerably reduce decoding complexity without performance loss compared with conventional algorithms.