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Coriolis mass flowmeter (CMF) is widely used in the industrial field. In mass flow measurement, there are many impurities in measured fluids that will adhere to the inner wall of the vibrating tube of CMF. The vibration characteristics of CMF would change due to the structural change, i.e., wall clung state, which will generate the wall clung state fault. In this paper, aiming at the wall clung state fault of CMF, the finite element model of CMF is established based on ANSYS. The velocity distribution of fluid in the vibrating tube of CMF is analyzed, considering the fluid–structure interaction. The location of the wall clung state in a vibrating tube is determined. Then, the fault model is established. The mechanism of the vibration transmission characteristics outwards of CMF caused by the wall clung state is analyzed by harmonic response analysis. Finally, the failure mode of CMF is investigated.

This paper presents the multi-based experts Failure Effects Analysis (FEA). The experts' opinions differ substantially because the experts do not often agree on the level of the failure factors (failure probability, non-detection probability, severity of effect, and expected cost) and the functions/subsystems attributes (e.g., importance). Therefore, conflict always occurs in Group-based Failure Effects Analysis (GFEA). The approach uses fuzzy Risk Priority Category (RPC) and group decision-making techniques to study both the failure effects on the functions/subsystems and the failure risk category with uncertain information. In addition, the approach uses the compensated operators to allow the tradeoffs either among failure factors or among functions/subsystems attributes. A solved example is presented to demonstrate the Group-based Failure Effects Analysis (GFEA) application.

Reliability prediction using traditional approaches were implemented at earlier stages of electronics. But due to advancements in science and technology, the above models are outdated. The alternative approach, physics of failure provides exhaustive information on basic failure phenomenon with failure mechanisms, failure modes and failure analysis becomes prominent because this method depends on factors like materials, processes, technology, etc., of the component. Constant fraction discriminators which is important component in NFMS needs to study failure characteristics and this paper provides this information on failure characteristics using physics of failure approach. Apart from that, the combined physics of failure approach with the statistical methods such as design of experiments, accelerated testing and failure distribution models to quantify time to failure of this electronic component by radiation and temperature as stress parameters. The SEM analysis of the component is carried out by decapsulating the samples and studied the impact of stress parameters on the device layout.

The underground high-voltage power transmission cables are high value engineering assets that suffer from multiple deteriorations through-out life cycles. Recent studies identified a new failure mode – the pitting corrosion deterioration on the layer of phosphor bronze reinforcing tape, which protects the oil-filled power transmission cables from oil leakage due to deterioration of the leads heath. Two models estimating the phosphor bronze tape life were established separately in this study. The first model, based on mathematical fitting, is generated using a replacement priority model from the power supply industry. This is considered as an empirical-based model. The second model, based on the corrosion fatigue mechanism, utilizes the information of the pit depth distribution and the concept of pit-to-crack transfer probability. The Bayesian inference approach is the conjunction algorithm to update the existing probability of failure (PoF) model with the newly identified failure modes. Through this algorithm, the integrated PoF model contains a more comprehensive background information while maintaining the empirical knowledge on the engineering assets’ performance.

Friction Stir Welding (FSW) was carried out on AA2219-T87 alloy plates with various process parameters. Multiparametric optimization was carried out using Taguchi-Grey Relational Analysis (T-GRA) to determine the most influencing factors on the responses like Ultimate Tensile Strength (UTS) and Yield strength (YS) of AA2219-T87 butt joints. In this work, defect-free welding parameters were selected from the wide range of trial and L18 Taguchi Mixed factorial design was fit to further optimize the parameters by T-GRA techniques. Parameters like tool rotational speed, welding speed and tool profile were varied, tool tilt angle and thrust force were kept constant. The macro and microstructures were examined to correlate with tensile, yield and hardness property to analyze the predominant factor that would improve joint efficiency. Finer grains were found in nuggets when compared to other zones and the grain size was found to decrease from top to bottom due to centrifugal action. Scanning Electron Microscopy (SEM) studies were carried out on fracture tensile specimen to determine the mode of fracture in the different regions. EDS elemental mapping was done in fracture region of the tensile specimen and it was encountered that crack initiation is along the copper-enriched region. Tensile strength was reported to be 73% of the parent metal and optimized parameter combination was observed for tool with taper threaded pin profile that enhances metal flow.

In this study, La₂Zr₂O₇, Yb₂O₃ and Gd₂O₃-doped La${}_{1.4}$(Gd, Yb)${}_{0.6}$Zr₂O₇ thermal barrier coatings have been manufactured from the crystalline and amorphous feedstock by plasma spraying. The thickness of the bond coat is 100±25 $\mu$m and the thickness of the top coat is 250±25 $\mu$m. Thermal shock tests were carried out in furnace temperature of 1200^∘C. The thermal shock tests indicate that lifetime of the La${}_{1.4}$Gd${}_{0.6}$Zr₂O₇ coating has 55 cycles which is the highest thermal shock lifetime compared to other coatings in this study. The type of feedstock, amorphous or crystalline, strongly affects the thermal shock lifetime of La₂Zr₂O₇ coatings. Coating damage after thermal shock tests was investigated using scanning electron microscope to observe the microstructure and X-ray diffraction techniques to analyze the phase composition. The failure of coatings is mainly in consequence of the accumulation of stress between bond coat–ceramic coat interface due to thermal expansion coefficient differences and thermally grown oxide layer formation during thermal shock cycling tests.

Full-scale tests are conducted to investigate the load-bearing capacity and failure mechanism of power transmission towers subjected to various loading patterns (broken lines, wind and ice). Detailed finite element models of power transmission towers are established based on these experimental prototypes. To capture the member instability, the integral stability coefficients are obtained from different specifications and introduced into a user-defined material model. Subsequently, the failure analysis of power transmission towers is carried out using an explicit algorithm, and good agreement is found in comparison with experimental results. The results show that the proposed procedure is effective in simulating the power transmission tower failure process. The full-scale test and numerical simulation studies can provide a valuable database for the design of power transmission towers subjected to various loads.

Shear stress concentrations may promote damage and failure processes. Quantities of studies have focused on the direct shear loading test, while the analytical model has not yet been studied in depth. Aiming to fill the knowledge gap, the theoretical and numerical analyses of the shear stress distribution in the shear band were investigated. In order to reflect the variation in the stress state, the differential element method was first used. The shear stress distribution equation was derived from the stress equilibrium, geometric and physical equations. The shear stress distribution was plotted, using the proposed equation. After that, the ratio of yield strength to crack initiation strength was calculated. The analytical model was analyzed with FDEM simulation, and the results were compared with those obtained from the laboratory tests. Using the elastoplastic theory, the damage evolution and process in rock were characterized from laboratory scale. The implication for underground engineering analysis was finally discussed with a case study of strain rockburst in hard rock. The analytical model and results could provide a fundamental basis for stability analysis in geotechnical engineering.

A statistic analysis system for CNC lathes is constructed in this paper. Using this system, the field failure data of home-made CNC lathes can be collected and the probabilistic distribution of time between successive failures can also be determined. In order to find out the weakness of the traditional home-made CNC lathes, failure mode, effect and criticality analysis is carried out. Based on the detailed analysis of failure causes, reliability growth suggestions and actions to improve reliability of the weak subsystems for the CNC lathes are proposed. The experiments verify that these suggestions and measures can improve the reliability of home-made CNC lathes.

A series of spot-welding tests for 22MnB5 steel sheet with a thickness of 1.2 mm was carried out. The welding process and mechanical properties of the plate were analyzed. The results show that the welding pressure and welding current had remarkable effects on the properties of welding joint. Increase of welding current and extension of welding pressure is advantage to eliminate shrinkage porosity defects and could effectively enhance the strength of welding joint. Moreover, the analysis results of the mechanical properties and internal defects also show that the pre-heating pulse is conducive to a spot-welding joint of good performance.

In the low-voltage distribution system, electrical equipment failure will terminate the provision of power to the client. This could lead to the power supply and distribution system malfunctioning, thereby causing a widespread power outage. In this paper, the typical failure mechanism of a low-voltage circuit breaker is first set out. Using the TRIZ theoretical method and analysis tool, improvements are made to the low-voltage circuit breaker such that its typical defects are mitigated. TRIZ is also used to conduct research into the typical failure modes and to put forward new ideas and tools for electrical equipment failure analysis. These serve as a valuable reference for future studies.

Physical hardware trojan modifies registry values, leak sensitive data and result in device degradation failure. Therefore, there is great significance to develop effective hardware trojan detection methods and to study the logic circuit transmission characteristics and the chip degradation failure mechanism caused by physically injected hardware trojan. In this paper, ATLAS simulation devices were tested using hot carrier degradation (HCD) stress model to study the degradation failure process of injected hot carrier hardware trojan on a MOSFET device. Another MOSFET was combined with hot carrier injected hardware trojan MOSFET to establish an inverter logic circuit by utilizing the ATLAS device simulation system with SmartSpice simulator. The effects of physical hardware trojan and the W/L value of a hardware trojan transistor on logic circuit output characteristics were studied. The experimental results demonstrated that the negative impact of hardware trojan on logic circuit DC current output characteristic is more significant than the AC transient time characteristic. Therefore we propose a convenient and effective method to detect the injection of physical hardware trojan in packaged chips. Moreover, the test procedure is a feasible operation method to detect physical hardware trojans.

In order to solve the problem that classical criticality analysis can't indicate randomness and fuzziness of mechanical failure, a new method of failure analysis is presented based on triangular fuzzy number. Considering influence of fault frequency, maintenance costs, maintenance time, fault effect, decision matrix is established with triangular fuzzy number. In order to reduce subjective influence of determining weights by experts directly, linear programming equations are established to obtain weights by Hausdorff distance. Finally, through establishing possibility degree matrix at different levels of risk attitude, criticality rank of each failure mode is obtained. Taking a case study of XK7132 CNC milling machines, the results show that bearing failure is the most hazardous failure mode. Compared with classical criticality analysis, method in this paper is more scientific and reasonable, and provides a theoretical basis for improving reliability of CNC milling machine.

The main reasons for corrosion failure of pipeline in sour gas field have been proposed based on the analysis techniques of Optical Microscopy (OM), Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and X-ray Diffraction (XRD). The results show that the leakage happened caused by pit corrosion in the test samples. Pit corrosion occurs under the condition of wet H₂S corrosion, while fouling and Cl^- do promotion. Test pipe material properties meet the conditions requirements of China. According to the condition of pipeline corrosion, it is suggested that the raw gas should process gas-water separation before transportation, and the filter unit should be added to reduce the sand and gravel content.