Failure Analysis Of Components Research Articles

Design and destructive testing of high-value hook fabricated by laser metal deposition

Laser metal deposition (LMD) provides an emerging opportunity for the economic fabrication of high-value components at low production volume. Despite the technical and commercial opportunities associated with LMD, there exist potential failure-modes that differ from those typical of traditional manufacture; concurrently, LMD is typically applied to high-value components associated with a high consequence of failure. This report contributes to the emerging literature on LMD component design and failure analysis by documenting the design and destructive testing of a high-value tensile loaded hook component, including numerical structural simulation, manufacture characterisation, microstructural analysis and instrumented destructive testing. This systematic design contributes to the understanding of LMD design for structural integrity and supports the application of LMD as a robust commercial additive technology.

Exploring the impact of thickness, scale and printing sequence on the tensile and fracture properties of PLA specimens fabricated via fused deposition modeling

Geometrical factors play a key role in determining the dimensional accuracy and mechanical properties of additively manufactured components. This research investigates the influence of thickness, scale, and printing sequence on Polylactic Acid (PLA) specimens produced via Fused Deposition Modeling (FDM) with special focus on tensile and fracture properties of the printed parts. The trends of experimental results were then linked to the microstructures and observations on failure mechanisms and the fabrication process conditions. Tensile test results indicate that increasing the build thickness significantly boosts elongation at failure and slightly raises ultimate tensile strength, while downscaling the printed specimens initially causes minor decreases, but further reductions lead to significant drops in mechanical properties due to higher ratio of intrinsic defect to specimen size. Similar to the tensile properties, fracture analyses revealed that larger build thickness and smaller scale of printed parts lead to lower fracture resistance, with an increasing impact by scale reduction, which is attributed to the formation of defects during fabrication and the thermal history of the printed parts. Printing sequence was found to have limited impact on the mechanical performance of the printed parts with effects below 10%. Additionally, a boundary effect model was employed to evaluate fracture behavior of tested specimens, demonstrating its applicability as an engineering tool for fracture prediction of FDM parts with different scales and thicknesses. The findings of this work underscore the importance of considering geometric factors and printing strategies for effective design and failure analysis of additive manufacturing components.

Evolution and formation mechanism of residual stress in Al-Cu alloy rings during ring rolling and quenching

The large-scale ring components, as thin-walled structures, are prone to unpredictable machining deformation due to the initial residual stresses introduced by rolling and quenching, which seriously affect the dimensional accuracy and service life of the ring components. Therefore, the relief and homogenization of residual stress inside large-scale ring components is crucial. However, the existing studies rarely involve the essential causes and the evolution laws of residual stresses during the manufacturing of ring components, which are indispensable for understanding the failure mechanisms of components caused by residual stresses and specifying relevant protective measures. Therefore, the evolution and distribution laws of stress-microstructure-property non-uniformity during the hot forming (ring rolling) and heat treatment (quenching) of 2219 Al-Cu alloy rings were precisely and deeply explored using scaled experiments in this paper. The relationship between non-uniform deformation and residual stresses was analyzed, and the basic equation that residual stresses must satisfy was established. Furthermore, the concept of the “non-coordination coefficient” was proposed, revealing the physical mechanism of residual stresses induced by non-uniform deformation. In addition, the influencing factors and formation mechanisms of residual stresses in the rolled and quenched state of rings were studied, and the essential reasons for the differences in residual stresses between the rolling and quenching processes were obtained. The experimental results indicate that the circumferential and axial residual stresses increased from 1.48 and 0.51 MPa to −142.68 and −122.31 MPa, respectively. The standard deviation changed from 13.47 and 33.52 MPa to 63.42 and 61.61 MPa, respectively. The maximum range of tensile strength, yield strength and elongation rates of the rolling and quenched state is 12.82 and 20.16 MPa, 17.49 and 22.14 MPa, and 8.62 % and 7.56 %, respectively. All fractures are microporous aggregation ductile, including dimple transgranular fracture and intergranular fracture. The quenched state exhibits a significantly larger grain size compared to the rolled state. The appearance of residual stress is essentially to force the inconsistent deformation of various parts inside the object to maintain its integrity and continuity, which leads to a local mismatch of micro-elements inside the ring and further induces non-uniform strain and stress. The difference in the severity of “penetrability” induced by different temperature gradients determines the difference in residual stress between rolled and quenched rings, larger rings have higher and more non-uniform residual stress than smaller rings under the same process conditions. The above results deepen the theoretical understanding of residual stress formation mechanisms and lay a theoretical foundation for the comprehensive evaluation of performance degradation and service failure analysis of large ring components.

Scenario-based anticipatory failure determination and patent technology inspiration for product innovation design

Exploring opportunities of technologies for product is critical in the highly competitive market. Anticipatory failure determination (AFD) identifies likely failure modes of a product, which provides a tool to explore the technology opportunities for product improvement. The existing methods of AFD are limited in the failure analysis of system components and the acquisition of technical solutions for the failure cause is depending on designer experience. This research proposes an approach to product innovation design based on the scenario-based evolution of AFD and patent technology inspiration. Scenarios obtained based on the proposed scenario generation rules are used to form failure events from the product function level. The failure events are then used to explore technical opportunities based on the anticipatory failure determination. A word vector model is trained with the patent data to extract patent technology terms in combination with the semantic similarity of the functional basis. The Latent Dirichlet Allocation (LDA) is used to cluster patent technologies. The best technical solution is finally selected based on the relative technology maturity and technological distance. The TRIZ tool is used to resolve possible conflicting problems. A complete product innovation design process is proposed from the technology opportunity exploration to concept design formation.

Numerical and Experimental Failure Analysis of Steel Components in a High-Voltage Transmission Tower Structure

Numerical and Experimental Failure Analysis of Steel Components in a High-Voltage Transmission Tower Structure

Failure Analysis and Technical Development of Electronic Components

The failure analysis involves researching a product to identify its failure mechanism and components. This allows for targeted improvements to prevent subsequent issues and enhance the product’s stability. In the context of electronic component failure analysis, testing and analysis are employed to elucidate the failure process and identify the underlying causes, ensuring the smooth operation of components. This paper introduces some simple and cost-effective analysis methods. During the electronic component failure analysis, sensory examination and internal analysis can aid in judgment. Leveraging extensive analysis experience and utilizing relevant facilities correctly can lead to cost reduction and an increased success rate.

Failure Analysis and Reliability Aspects of Electronic Components

Failure analysis (FA) is the process of determining the cause of failure, collecting, and analysing data, and developing conclusions to eliminate the failure mechanism (FM) causing specific device or system failures. Why it is so important to use FA, i.e. to know the cause of product failure, this is what we intend to describe in this article. Reliability analysis is not at all the only ‘customer’ of FA. Other fields, such as business management and military strategy are using this term. In order to offer to the reader a more complete picture, we identified the possible applications of FA in various fields (industry, research, etc.), which are detailed in the article.

Corrosion Failure Analysis of Downhole Pump Components After Short Service in Oil Production

Corrosion Failure Analysis of Downhole Pump Components After Short Service in Oil Production

Relevant input data for crack feature segmentation with deep learning on SEM imagery and topography data

Fractography plays a critical role in failure analysis of engineering components and has a considerable importance for safety investigations. Usually, the interpretation of fracture surfaces is done by experts with the help of literature and experimental data, that requires a lot of experience. The use of deep learning (DL) with neural networks in failure analysis becomes more and more relevant with the rapidly developing possibilities. Especially, the modern network architectures can assist fractographers in determining various fracture features on SEM images of the fracture surfaces. The basis for the best possible evaluation is the understanding of the influence of the input data used for training deep neural networks (DNN). Therefore, this study discusses the influence of the selection of the input data used for the prediction quality of these networks in order to take this into account for future data acquisition. Specimens of various metallic materials were subjected to fatigue cracking experiment under laboratory conditions. The fractured surfaces were then imaged using various modes or detectors (such as SE, BSE and topography) in SEM, and those captured images were used to create a training data set. The relevance of the individual data for the quality of the prediction is determined by a specific combination of the different detector data. For the training, the well-established architecture of a UNet-ResNet34 with a fixed set of hyperparameters is used. It has been found in this present study that the combination of all input data significantly increases the prediction accuracy, whereby even the combination of SE and BSE data provides considerable advantages over the exclusive use of SE images.

Utilizing Fourier Transform Infrared Spectroscopy for Plastics Failure Analysis

Abstract This article explores one of the most commonly used analytical techniques in plastic component failure analysis—Fourier transform infrared spectroscopy—along with a case study to demonstrate its use.

Prediction of Mechanical Properties in the Sub-Critical Heat Affected Zone of AHSS Spot Welds Using Gleeble Thermal Simulator and Hollomon-Jaffe Model

Measuring the mechanical properties of weld Heat Affected Zone (HAZ) remains one of the main challenges in the failure analysis of spot-welded components. Due to the small size of the HAZ and variation in the temperature history, different peak temperatures and cooling rates impose a range of phase transformations across the resistance spot weld. Among the HAZ sub-regions, the sub-critical HAZ (SCHAZ), which experiences temperatures below AC1 (350–650 °C), usually shows a reduction in the hardness in most of the modern AHSS grades due to the martensite tempering phenomenon. SCHAZ softening may lead to strain localization during loading. Therefore, it is important to characterize the local properties of the SCHAZ region to accurately predict RSW failure. However, it is not feasible to extract standard mechanical test specimens out of the SCHAZ of the spot-welded structure due to its small size. In this work, the SCHAZ of the spot weld for two AHSS, 3G-980 and PHS-1500, was simulated using a Gleeble® (Dynamic Systems Inc., 323 NY-355, Poestenkill, NY 12140, USA) 3500 thermo-mechanical simulator. An in-situ high-speed IR thermal camera was used to measure the entire temperature field during the Gleeble heat-treatment process, which allowed for the visualization of the temperature distribution in the gauge area. The temperature and hardness data were fit to a Hollomon-Jaffe (HJ) model, which enables hardness prediction in the SCHAZ at any given temperature and time. Using the HJ model, a heat treatment schedule for each material was chosen to produce samples with hardness and microstructure matching the SCHAZ within actual spot weld coupons. Tensile specimens were machined from the coupons heat treated using simulated heat treatment schedules, and mechanical testing was performed. The results showed that the 3G-980 SCHAZ has a slight increase in yield strength and tensile strength, compared to the base metal, due to the formation of fine carbides within the microstructure. In contrast, the SCHAZ of PHS-1500 showed a significant reduction in the yield and tensile strength with yield point elongation behavior due to the reduction of the martensite phase and an increase in carbide formation due to the tempering process.

A brief guide to conducting failure analysis on ceramic components

Abstract Failure investigations are mainly conducted for the purpose of clarifying the root causes for component failure. Possible aims of these investigations are to analyze the unexpected failure of a component during operation, to improve the material and to assess the quality of a product. Usually, ceramics can be used in similar ways as other structural materials. There are particularities, however, which need to be considered in failure analysis of ceramic components. This paper will therefore give a brief overview of the types of damage which may occur in ceramic materials, with the focus being on failures occurring at room temperature and medium temperatures (e. g., brittle fracture, contact stresses or stresses caused by rapid temperature changes).

Failure Analysis of Boron Steel Components for Automotive Applications

The automotive industry is continuously looking for an innovative mix of new steels and manufacturing techniques in order to improve process chain efficiency and cost reduction. To this aim, boron steels are becoming increasingly popular thanks to their high hardenability and machinability. Due to their reduced finishing steps, boron steels are commonly processed using fine blanking technologies. The success of fine blanking on boron steel components is due to heat treatments which must be carefully designed to avoid precipitation of boron-rich compounds that would lower steel hardenability. At high temperature, boron is very reactive with oxygen and nitrogen. The main focus of this paper is to show some drawbacks that can occur during heat treatments of automotive components. An experimental campaign was performed on two different boron steels, namely EN 34MnB5 and EN 22MnB5. The steel samples were previously spheroidized annealed in a neutral environment (hydrogen/nitrogen atmosphere), and then fine blanked to obtain specific automotive components which were subsequently quenched and tempered. Experimental tests revealed precipitation of nanometric compounds, causing strong grain refinement and localized decrease of steel hardenability. Hardenability problems were brought back to nitrogen pick-up during initial spheroidize annealing treatments.

RF Overdrive Burnout Behavior and Mechanism Analysis of GaN HEMTs Based on High Speed Camera

In this work, a new method for failure analysis of electronic components, high speed camera, is used to investigate burnout failure location of GaN HEMTs under RF overdrive stress. Based on the high speed camera system and the RF test system, we can filter out most of the burn flashes, and clearly locate the weak parts of devices. To further explain the burnout mechanism, a long-term (100 h) RF overdrive stress experiment was carried out and the significant degradation was observed. The drain-source current decreases and the threshold voltage drifts forward. These phenomena show that the degradation of RF overdrive stress is based on hot electron effect (HEE), which is related to the electric field. Besides, Electroluminescence (EL) tests are used and the non-uniform but strong luminescence characteristics of the gate were found, which indicates the strong electric field is the main cause of burnout. We also explore the correlation between burnout and ambient temperature. It was found that the influence of ambient temperature on the burnout was limited. At last, a TCAD simulation is carried out to confirm the temperature and electric field distribution in the device when burnout. It can be found that the electric field inside the device exceeded the breakdown electric field of GaN, which further proves that the burnout caused by RF overdrive is mainly due to electric field rather than temperature.

Analysis of boiler tubes using gas tungsten arc welding in Grade 91 alloy steel

Failure analysis of Boiler components is an important step in the Inspection process of Boiler. If this is not taken sternly, it may lead to leakage or even bursting. So research works should be conducted to upgrade the quality of the material and ensure the effectiveness of the components like boiler tubes. In this paper an experiment is conducted by welding Grade 91 Alloy steel with proper process parameters. The joints are then subjected to Non– Destructive Testing and the final conclusion is discussed at the end. Grade 91 alloy seems to be suitable for boiler tube material. If applied proper welding techniques, an effective boiler tubes can be obtained.

Analysis of the Causes of Failure and Material Analysis of Components of the Screw Conveyor of a Coal Boiler for Steam Production

The paper summarizes results of failure root cause analysis of the driven part of the screw conveyor shaft for transfer of combustion residues (ash and slag) of a power plant steam boiler. The paper presents also the results of material analysis of selected components of this conveyor to be evaluated their material quality.

Failure analysis of 3D-printed PLA components: Impact of manufacturing defects and thermal ageing

The significant increase in applications of additive manufacturing has led to various investigations in this field. Three-dimensional (3D)-printed parts might be subjected to different environmental conditions during their service life. Therefore, a profound knowledge on this subject can significantly help to increase structural performance of these parts. In the present study, effects of accelerated thermal ageing on the mechanical behavior of 3D-printed parts has been investigated. To this aim, a natural environment has been simulated and the related effects are investigated by means of accelerated thermal ageing with temperature in the range of −5 °C to 35 °C. Moreover, the current study describes influence of manufacturing defect on the fracture behavior of 3D-printed components. Since defects and anomalies might be occurred during 3D printing process, fabricated parts can show different mechanical behaviors. In the present investigation, intact and defected test coupons with different raster orientations were printed and examined. In detail, polylactic acid material was used in fabrication of the specimens based on the fused deposition modeling process. These groups of specimens were also aged and subjected to tensile load. The documented results indicate effects of thermal ageing on the structural integrity of intact and defected specimens. The outcome of this study can be utilized for future design and next computational modeling of 3D-printed polymer parts.

Torsional Overload Fracture of Twist-off Bolts During Assembly

Abstract Supposedly simple cases of failure are most often best suited to communicate the principles of component failure analysis in the field of materials engineering to a wide readership, especially to those peers in the specialist community who are just beginning to familiarize themselves with the subject. The present case of failure relates to components that failed as early as during the assembly, and more specifically, during the final assembly stage of combustion chamber components for heavy-duty gas turbine engines. Hence, they lost their functionality (in fact, the common definition of component failure). At tightening torques of the nuts opposite of the tapered heads as low as below 25 Nm, so-called twistoff bolts which, when welded into combustion chamber sheets, take on the function of stud bolts, sheared off. By way of exception, a materialographic failure analysis could show that the primary cause of the failure was not the component’s design, but the disregard of the drawing specifications during final assembly. However, on a secondary level, design deficiencies had to be mentioned, as untempered welded joints in martensitic chromium steels invariably act as metallurgical notches. If the respective part is subjected to dynamic loads, as is the case in virtually all turbo machinery, they are thus to be avoided.

Failure assessment of corrosion affected pipeline networks with limited failure data availability

Many pipeline networks around the world do not have a failure history. Because of financial reasons or lack of technology, this is a common issue for asset managers in developing and under-developed countries. In the case of data scarcity, it is not straightforward to assess the risk and reliability of such systems. This research proposes a probabilistic framework for analysing the reliability of corroded pipeline networks with limited failure history availability. To achieve this aim through a comprehensive reliability assessment methodology, state-of-the-art corrosion modeling, component and system failure analysis techniques are utilized. A variety of spatio-temporal reliability assessment methods are employed along with the random-field representation of spatially variable parameters to estimate the failure in a large-scale corrosion affected pipeline network. The applicability of the methodology is evaluated through a case-study of buried pipeline network, and the results are verified with failure history data reported by the industry. The results obtained from the proposed methodology, combined with the cost data provided by asset managers make accurate risk assessment of process/water pipeline possible.

Framework for probabilistic simulation of power transmission network performance under hurricanes

Structures in a power transmission network, such as towers and conductors, are vulnerable to hurricanes. Failures of these structures trip transmission lines and usually result in large scale power outages in the region. This paper presents a technique for the probabilistic simulation of power transmission systems under hurricane events and provides fundamental insights on the modeling and quantification of power system performance and resilience. The study models the power transmission system as a network of connected individual components, which are subjected to wind-induced mechanical failure and power flow constraints. A realistic power transmission network is developed for the study region. The geographical data are obtained for all components in the network based on a data collection and image processing campaign to reflect the realistic properties of the network serving the Lehigh Valley, PA. A hurricane simulator is utilized to generate a hurricane scenario providing time-varying wind intensities and wind directions for the component failure analysis. The spatio-temporal impact of the hurricane is investigated: a pool of component fragilities is generated to effectively incorporate the uncertainties in structural capacities into the analysis; the spatial correlation among structures is modeled efficiently by a random field based technique. At the system level, Monte Carlo simulation is adopted to determine the failure probability of transmission lines. The unmet demand of the system is computed probabilistically, based on the alternate current optimal power flow analysis, capacity constraints and load shedding process of the system. The simulation results can be used to quantify and visualize the power network performance, and help decision makers to identify critical components in the network to optimize the short-term pre-event preparation for an approaching hurricane and long-term retrofit strategy to enhance system resilience.