Breakage Detection Research Articles

Mechanical fatigue resistance of an implantable branched lead system for a distributed set of longitudinal intrafascicular electrodes

Objective. A neural interface system has been developed that consists of an implantable stimulator/recorder can with a 15-electrode lead that trifurcates into three bundles of five individual wire longitudinal intrafascicular electrodes. This work evaluated the mechanical fatigue resistance of the branched lead and distributed electrode system under conditions designed to mimic anticipated strain profiles that would be observed after implantation in the human upper arm. Approach. Custom test setups and procedures were developed to apply linear or angular strain at four critical stress riser points on the lead and electrode system. Each test was performed to evaluate fatigue under a high repetition/low amplitude paradigm designed to test the effects of arm movement on the leads during activities such as walking, or under a low repetition/high amplitude paradigm designed to test the effects of more strenuous upper arm activities. The tests were performed on representative samples of the implantable lead system for human use. The specimens were fabricated using procedures equivalent to those that will be used during production of human-use implants. Electrical and visual inspections of all test specimens were performed before and after the testing procedures to assess lead integrity. Main results. Measurements obtained before and after applying repetitive strain indicated that all test specimens retained electrical continuity and that electrical impedance remained well below pre-specified thresholds for detection of breakage. Visual inspection under a microscope at 10× magnification did not reveal any signs of damage to the wires or silicone sheathing at the stress riser points. Significance. These results demonstrate that the branched lead of this implantable neural interface system has sufficient mechanical fatigue resistance to withstand strain profiles anticipated when the system is implanted in an arm. The novel test setups and paradigms may be useful in testing other lead systems.

Reliable Detection of Rotor Bars Breakage in Induction Motors via MUSIC and ZSC

Induction motors are used in a variety of industrial applications where frequent startup cycles are required. In those cases, it is necessary to apply sophisticated signal processing analysis methods in order to reliably follow the time evolution of fault-related harmonics in the signal. In this paper, the zero-sequence current (ZSC) is analyzed using the high-resolution spectral method of multiple signal classification. The analysis of the ZSC signal has proved to have several advantages over the analysis of a single-phase current waveform. The method is validated through simulation and experimental results. The simulations are carried out for a 1.1-MW and a 4-kW induction motors under finite element analysis. Experimentation is performed on a healthy motor, a motor with one broken rotor bar, and a motor with two broken rotor bars. The analysis results are satisfactory since the proposed methodology reliably detects the broken rotor bar fault and its severity, both during transient and steady-state operation of the induction motor.

Micro Milling Cutter Breakage Detection Based on Wavelet Singularity and Support Vector Machine

Micro Milling Cutter Breakage Detection Based on Wavelet Singularity and Support Vector Machine

Single-end-access distributed strain sensing with wide dynamic range using higher-speed Brillouin optical correlation-domain reflectometry

Single-end-access real-time fiber-optic distributed strain sensing has recently been demonstrated using an ultrahigh-speed configuration of Brillouin optical correlation-domain reflectometry (BOCDR). Its extremely high sampling rate was, however, achieved at the cost of a limited strain dynamic range (<0.2%). Here, by employing a noise-floor compensation technique, we develop a new cost-effective higher-speed configuration of BOCDR with a wide strain dynamic range (up to 2.0%; evaluated by static strain measurement). This value is larger than that of any other BOCDR configuration. Using this configuration, we demonstrate some fundamental distributed strain measurements and breakage detection.

Mutagenicidade do naftaleno através do teste do micronúcleo: estudo em modelo animal (Astyanax altiparanae) e vegetal (Tradescantia pallida purpurea)

Os hidrocarbonetos Aromáticos Policíclicos, como o Naftaleno, são considerados poluentes orgânicos prioritários em estudos ambientais. Alguns apresentam elevado potencial de toxicidade e podem ser precursores de efeitos mutagênicos e carcinogênicos. O teste de micronúcleo é uma ferramenta sensível na detecção de eventos clastogênicos e aneugênicos ocasionados por xenobióticos. O objetivo deste trabalho foi avaliar a mutagenicidade do naftaleno após exposição aguda em um modelo animal e um vegetal. Os bioindicadores foram a espécie de peixe Astyanax altiparanae e a planta Tradescantia pallida purpurea. No teste de micronúcleo písceo nenhum dos tratamentos apresentou diferença significativa com o controle negativo. No teste em células-mãe do grão de pólen de Tradescantia a concentração de 0,3 mgL-1 apresentou mais micronúcleos em relação ao controle negativo. O Trad-MCN demonstrou maior sensibilidade na detecção de quebras e perdas cromossômicas ocasionadas pelo naftaleno.

An investigation on stressing and breakage response of a prestressing strand using an efficient finite element model

The mechanical response of a wire strand is inherently complex because the helical wires undergo evolving stress and contact conditions as the strand is loaded. Further complications are added to the strand behavior if one or more of the wires break due to strand degradation over time. Although a detailed investigation on strand behavior is critically important for predicting the capacity of a broken strand as well as developing new monitoring approaches for wire break detection, there is little study available in the literature on wire breakage in a stressed strand. This paper provides an extensive investigation on stressing and post-breakage dynamic behavior of a prestressing strand. A finite element model is generally useful to study the global strand response, along with many localized phenomena that have strong influence on its performance, but are difficult to capture either experimentally or through closed-form analytical models. Investigations on certain behaviors, such as wire breaks, however, require a relatively large or even a full-scale model to adequately develop contact and frictional conditions. Moreover, such a sizeable model can account for any deviation points and may avoid edge effects. Consequently, several finite element parameters, such as the load ramp profile and duration, effects of damping and interwire friction, become critical for an accurate and efficient model. This paper first presents the use of a parametrized model to study strand behavior and evaluates the effects of these modeling parameters on strand response; load distribution and redistribution among the wires at the onset of interwire motion are also considered. The model is then used to simulate wire breakage in a prestressing strand, so that various aspects of post-breakage response can be examined. Numerical results show that a linear load ramp or stressing too quickly may lead to an inaccurate axial tension developed in the strand, whereas the inclusion of nominal mass-based damping has been found effective in achieving a quasi-static solution at a reasonable computational cost. In addition, the wire break simulation results indicate that breakage of an outer wire results in greater prestress loss than breakage of the center wire, which might have important implications for non-destructive wire breakage detection.

Full-scale experimental investigation of wire breakage detection in deviated multi-strand tendon systems

The use of post-tensioning tendons with flexible filler is expected to increase in U.S. bridges in the coming years as an alternative to grouted tendons. Flexible filler results in purely unbonded behavior when used with either internal or external tendons, which creates opportunities for the application of tendon monitoring techniques that were not possible with grouted tendons. One such technique is the detection of wire breakage based on the strain response of the post-tensioning anchorage. The encouraging results from simplified laboratory experiments and analytical models in support of the proposed method motivated the full-scale experiments reported in this paper. Tests were conducted with flexible filler in both external and internal tendons in I-girder specimens having deviated multi-strand tendon profiles, allowing the investigation of the effects of deviators on stress recovery and anchor strain response. The strands of the post-tensioned girders were detensioned by individual wire cuts and the resulting changes in anchor strain distribution were captured. Finally, a broken strand identification algorithm developed for automated damage detection was applied to the experimental results. In addition to instrumenting the anchors with strain gauges, an acoustic sensing system was employed to independently monitor and confirm the breakage events. The findings reported in this study suggest that the wire breakage detection method based on anchor strain measurement can be a reliable and cost-effective approach for in-field bridge monitoring applications.

Tool breakage detection from 2D workpiece profile using vision method

In-process tool breakage monitoring can significantly save cost and prevent damages to machine tool. In this paper, a machine vision approach was employed to detect the tool fracture in commercial aluminium oxide ceramic cutting tool during turning of AISI 52100 hardened steel. The contour of the workpiece profile was captured with the aid of backlighting during turning using a high-resolution DSLR camera with a shutter speed of 1/4000 s. The surface profile of the workpiece was extracted to sub-pixel accuracy using the invariant moment method. The effect of fracture in ceramic cutting tools on the surface profile signature of the machined workpiece using autocorrelation was studied. Fracture in the aluminum oxide ceramic tool was found to cause the peaks of autocorrelation function of the workpiece profile to decrease rapidly as the lag distance increased. The envelope of the peaks of the autocorrelation function was observed to deviate significantly from one another at different workpiece angles when the tool has fractured due to the continuous fracture of ceramic cutting insert during machining.

Measurement of Micro-Drill Breakage during PCB Drilling

Due to the weak rigidity of micro-drills and impulse effects, the micro-drill breakage is a common problem in printed circuit board micro-drilling. Traditional micro-drill breakage detection methods and principles, including vacuum-type, laser-type, and contact-type detection, were reviewed in this paper. The comparison of three detection methods showed that the contact-type detection can more satisfy the performance of CNC drilling machine. Three effective contact-detection circuits, including no transformer and rectifier circuit pulse-type, active-type, and trigger-type detection circuit, were introduced. And as a conclusion, differences of these detection methods were compared. Based on the characteristic of three effective micro-drill breakage contact detection circuits, the development trends and designs of innovative detection circuit were proposed to meet the challenges in micro-drill breakage measurement during PCB drilling.

The effect of cryogenic cooling and minimum quantity lubrication on end milling of titanium alloy Ti-6Al-4V

The cooling down of cutting temperature in machining is very important for the improvement of tool life, especially when dealing with work materials that have low thermal conductivity such as titanium alloy. In this study designed to investigate the machining performance of a variety of cooling methods, cryogenic, Minimum quantity lubrication (MQL), and flood cooling are performed on solid end milling of titanium alloy, Ti-6Al-4V. In particular, the effect of internal and external spray methods on cryogenic machining is analyzed with a specially designed liquid nitrogen spraying system by evaluating tool wear and cutting force at cutting conditions. The cutting force is also analyzed for tool breakage detection. As a result, the combination of MQL and internal cryogenic cooling improves tool life by up to 32% compared to conventional cooling methods. The cutting force is also reduced significantly by this combination of cooling and lubrication strategy of side end milling.

Evaluation of environmental genotoxicity by comet assay in Columba livia

The concentrations of recognized or suspected genotoxic and carcinogenic agents found in the air of large cities and, in particular, developing countries, have raised concerns about the potential for chronic health effects in the populations exposed to them. The biomonitoring of environmental genotoxicity requires the selection of representative organisms as “sentinels,” as well as the development of suitable and sensitive assays, such as those aimed at assessing DNA damage. The aim of this study was to evaluate DNA damage levels in erythrocytes from Columba livia living in the metropolitan area of Monterrey, Mexico, compared with control animals via comet assay, and to confirm the results via Micronuclei test (MN) and DNA breakage detection–fluorescence in situ hybridization (DBD–FISH). Our results showed a significant increase in DNA migration in animals from the area assayed compared with that observed in control animals sampled in non-contaminated areas. These results were confirmed by MN test and DBD–FISH. In conclusion, these observations confirm that the examination of erythrocytes from Columba livia via alkaline comet assay provides a sensitive and reliable end point for the detection of environmental genotoxicants.

Designing a system for measuring the flow of material transported on belts using ultrasonic sensors

Excavation tailings (scraping) and extracting the useful (lignite) in surface mine pits in Mining Basin Oltenia is achieved with technological lines of excavation - transport - dump of high productivity. A correlation of working capacity of the main components of technological lines (motor rotor, high capacity transport, car dumps) is necessary for economic reasons on electricity consumption. To achieve experience in the process was chosen excavator SRS 1400 from South Jilt career in the CET Turceni. The question of coal excavated volume has a great importance in the mine pits. At the excavation is desired a density estimate for each machine production tracking, cost estimation and tracking product unit profitability of each band on various sections zones. Permanent display size excavated volume snapshots in the excavator's cabin permits to track tape loading, eliminating unproductive times and information management to determine profitability. Another important requirement is closing the loop of the machine drive system of an excavator for a uniform deposition of carbon on the strip, thus achieving automatic control of the loading belt. Such equipment is important for the system dispatching in surface mine pits. Through a system of three ultrasound transducers to determine the smart instant of coal excavated section which, coupled with the tape speed, integrated over time will determine the amount of excavated coal. The basis of the system developed is a device for determining the volume and quantity of coal excavated acting on the march and optimize the system speed excavator working order. The device is designed primarily following the careers of lignite production: rotor excavators, rubber conveyor belts and dump facilities. Newly developed system aims to achieve the following determines: the optimum energy excavation depending on the nature of excavated material - lignite, shale, clay, etc., economic times to use the excavator bucket teeth rotor, energy optical regime to rubber belt conveyors, eliminate damage to the plant by conveyor belt breakage detection or tread and eliminating time and energy losses by limiting reproductive idle, monitoring the amount of coal excavated, control power consumption. Systems in general and particularly automated systems cannot be designed without taking into account their degree of effectiveness, compliance with minimum consumption of time, energy and materials, insofar as they are requested and used all the resources it has, at minimum cost production, etc. For this reason any matter of calculation, design, analysis and operation of transport systems continuously subordinate requirements optimality.

A strain-based wire breakage identification algorithm for unbonded PT tendons

Tendon failures in bonded post-tensioned bridges over the last two decades have motivated ongoing investigations on various aspects of unbonded tendons and their monitoring methods. Recent research shows that change of strain distribution in anchor heads can be useful in detecting wire breakage in unbonded construction. Based on this strain variation, this paper develops a damage detection model that enables an automated tendon monitoring system to identify and locate wire breaks. The first part of this paper presents an experimental program conducted to study the strain variation in anchor heads by generating wire breaks using a mechanical device. The program comprised three sets of tests with fully populated 19-strand anchor head and evaluated the levels of strain variation with number of wire breaks in different strands. The sensitivity of strain variation with wire breaks in circumferential and radial directions of anchor head in addition to the axial direction (parallel to the strand) were investigated and the measured axial strains were found to be the most sensitive. The second part of the paper focuses on formulating the wire breakage detection framework. A finite element model of the anchorage assembly was created to demonstrate the algorithm as well as to investigate the asymmetric strain distribution observed in experimental results. In addition, as almost inevitably encountered during tendon stressing, the effects of differential wedge seating on the proposed model have been analyzed. A sensitivity analysis has been performed at the end to assess the robustness of the model with random measurement errors.

A PNN self-learning tool breakage detection system in end milling operations

With the advance of technology over the years, computer numerical control (CNC) has been utilized in end milling operations in many industries such as the automotive and aerospace industry. As a result, the need for end milling operations has increased, and the enhancement of CNC end milling technology has also become an issue for automation industry. There have been a considerable number of researches on the capability of CNC machines to detect the tool condition. A traditional tool detection system lacks the ability of self-learning. Once the decision-making system has been built, it cannot be modified. If error detection occurs during the detection process, the system cannot be adjusted.To overcome these shortcomings, a probabilistic neural network (PNN) approach for decision-making analysis of a tool breakage detection system is proposed in this study. The fast learning characteristic of a PNN is utilized to develop a real-time high accurate self-learning tool breakage detection system. Once an error occurs during the machining process, the new error data set is sent back to the PNN decision-making model to re-train the network structure, and a new self-learning tool breakage detection system is reconstructed. Through a self-learning process, the result shows the system can 100% monitor the tool condition. The detection capability of this adjustable tool detection system is enhanced as sampling data increases and eventually the goal of a smart CNC machine is achieved.

Detection of tool breakage during hard turning through acoustic emission at low removal rates

The paper deals with a new method for the detection and prediction of the catastrophic tool failure (CTF) of ceramic inserts through an acoustic emission (AE) technique and associated chip formation analysis during the hard turning of bearing steel 100Cr6. The capability of different AE sensors with respect to the different processes in the cutting zone during hard turning is discussed as an initial study. Then a new concept of process monitoring is suggested based on the application of two sensors and rationing of chosen parameters such as AErms, AEstrength and AEabsolute energy. The specific character of the formed chip is associated with raw AE signals. Conventional data processing of AE signals does not enable the different phases of tool wear to be clearly recognised or the prediction of CTF, while the new suggested concept does. This concept is based on the rationing of AE features recorded in different frequency ranges in connection with the different processes in the cutting zone during chip separation.

Towards optimising routing overhead in wireless multi-hop networks

In this paper, we select three most widely used reactive protocols; ad-hoc on-demand distance vector (AODV), dynamic source routing (DSR) and dynamic MANET on-demand (DYMO), and model their energy and time consumption costs of expanding ring search (ERS) algorithm in wireless multi-hop networks (WMhNs). A novel contribution of this work is tuning the route discovery and route maintenance parameters of the chosen protocols to minimise routing overhead. For analytical comparison, we simulate default and enhanced versions of these protocols using NS-2. From modelling and analytical comparison, we deduce that adjusting time-to-live (TTL) values in search sets of ERS algorithm with respective waiting time is more useful for reducing bandwidth and locating time in chosen protocols. Moreover, for reliable transmission and efficient performance, reactive protocols need immediate detection of link breakage along with quick repairement strategies for re-establishment of routes such as local link repair (LLR) and packet salvaging (PS).

Automatic tool touch and breakage detection in turning

The Machine Tool Monitor (MTM) described in this paper is a tool breakage detection and a tool and part probing system for use on lathes. It uses a single accelerometer, mounted on the turret structure, as the sensing element. The system processes the sensor signals, and is programmed to recognize signal patterns resulting from the breakage of the tool, and the touch of the tool to the rotating workpiece or to a vibrating reference post. The system is integrated with the lathe's NC control to allow automatic reaction to the sensed events.

An approach based on singular spectrum analysis and the Mahalanobis distance for tool breakage detection

The failure of cutting tools significantly decreases machining productivity and product quality; thus, tool condition monitoring is significant in modern manufacturing processes. A new method that is based on singular spectrum analysis and Mahalanobis distance are combined to extract the crucial characteristics from spindle motor current to monitor the tool's condition. The singular spectrum analysis is a novel nonparametric technique for extracting the properties of nonlinear and nonstationary signals. However, because the components are not completely independent, the original singular spectrum analysis eventually leads to misinterpretation of the final results. The proposed method is used to overcome the weakness of the original singular spectrum analysis. The singular spectrum analysis algorithm is adopted to decompose the original signal and the useful singular values that correspond to the tool condition can be extracted. The Mahalanobis distance of the singular values is proposed as a feature that can effectively express the tool condition. The experiments on a CNC Vertical Machining Center demonstrate that this method is effective and can accurately detect the tool breakage in mill process.

Cutting sound signal processing for tool breakage detection in face milling based on empirical mode decomposition and independent component analysis

Owing to the inherent complexity and variability of the machining process, the sound signals of the cutting process are usually polluted by chip breakage signals and environmental noise which makes it very difficult for tool breakage detection based on sound signals. An approach based on empirical mode decomposition (EMD) and independent component analysis (ICA) is presented to deal with the blind source separation problem of cutting sound signals in face milling with the objective of separating cutting oriented sound signals from those background noises. The advantage of EMD is its ability to adaptively decompose an arbitrary complicated time series into a set of components, called intrinsic mode functions (IMFs). With EMD, cutting sound signals in face milling process are composed into a set of IMFs. Using fast ICA to analyze these series, some independent components are obtained, from which different types of sound signals can be extracted. Experimental results show that the proposed EMD-ICA method is capable of separating cutting sound signals in face milling, where different source components related to a normal insert and a broken one are extracted successfully. This makes tool breakage detection possible.

Localisation and quantification of alkali-labile sites in human spermatozoa by DNA breakage detection-fluorescencein situhybridisation

The localisation and quantification of constitutive alkali-labile sites (ALSs) were investigated using a protocol of DNA breakage detection plus fluorescence in situ hybridisation (DBD-FISH) and alkaline single-cell gel electrophoresis (SCGE or comet assay), in spermatozoa of infertile and fertile men. Semen samples from 10 normozoospermic patients undergoing infertility treatment and 10 fertile men were included in this study. ALSs were localised and quantified by DBD-FISH. The region most sensitive to alkali treatment in human spermatozoa was located in the basal region of the head. ALSs were more frequent in spermatozoa of infertile men than in those of fertile men. These results were confirmed by SCGE comet assays. In conclusion, the most intense localisation of hybridisation signals in human spermatozoa, representing the highest density of constitutive ALSs, was not randomly distributed and was predominantly located in the base of the head. Moreover, infertile men presented with an increase in ALS frequency. Further studies are necessary to determine the association between ALS, sperm chromatin organisation and infertility.