Browse Topic: Failure modes and effects analysis (FMEA)
AMS6885/2 gives specific information about the qualification program for unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. The prepreg system shall include an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
With new energy vehicles developing rapidly, battery safety, as an important part of the impact on the range of new energy vehicles and vehicle safety, has become the focus of attention. The battery pack protection plate is a core component to protect the battery, its performance needs not only impact resistance, but also lightweight, honeycomb sandwich structure with its excellent energy absorption characteristics and weight reduction performance by the battery pack protection plate performance research. At present, the core-to-face sheet interaction in conventional sandwich structures subjected to impact loads has not been fully elucidated, and the quantitative characterization of damage is insufficient, so this paper aims to optimize the lightweight impact-resistant structure by exploring the synergistic energy dissipation mechanism between the high-strength core material and the steel plate. The study combines theory and simulation, adopting ideal rigid-plastic film theory to establish a critical response model to predict the structural failure threshold, equivalent single-layer theory to simplify the analysis of plywood, and a stiffness matrix model to quantify the structural mechanical contribution of each layer. A two-material synergistic design framework is proposed by fully considering the material properties and adopting the corresponding intrinsic structure and failure criteria for different materials. Analysis reveals that geometric confinement is a key characteristic of the honeycomb sandwich panel’s response and a strain gradient driving mechanism at low impact resistance, and a new energy distribution paradigm is found through the analysis of the energy absorption ratio. The theoretical and simulation results are in great agreement with each other, which just has a difference of 0.7% in the peak force, 1.4% in the critical displacement error, and less than 2% in the impulse integration error. The proposed dual-material co-design framework provides a solution for electric vehicle battery protection systems that balances lightweight and impact resistance.
A new modeling and simulation approach for uncrewed aerial vehicles (UAVs) for shipboard operations, as well as other complex airwake environments, is introduced. The approach couples an aerodynamic modeling framework, expanded with a closed-loop flight controller, with a flight dynamics solver to assess UAV responses in highly complex airwakes. Using high-fidelity wall-modeled large eddy simulation airwakes, the approach has been evaluated for two traditional naval approaches on a generic destroyer. As part of this effort, a new metric to ensure accurate flight modeling is introduced, along with proposed UAV safety mapping. These predictions can support mission planning by evaluating unique prescribed approaches for nontraditional small UAV, and can aid in early controller design by highlighting specific failure modes based on the airwake environment.
This paper presents the first systematic examination of Large Language Model (LLM) capabilities for automating the development of Failure Mode and Effects Analysis (FMEA) utilizing architectural diagrams as input. Although prior research has examined LLMs for FMEA tasks, our methodology incorporates innovative aspects, such as the direct analysis of architectural diagrams for component extraction, prediction of failure modes, causes, estimation of risk and a human-in-the-loop (Hu-IL) validation framework. We examine the capability of general-purpose LLMs to accurately automate the creation of FMEA by formulating a methodology that extracts components and signals from architectural diagrams, conducts automated component classification, and produces a comprehensive FMEA form sheet encompassing Severity, Occurrence, and Detectability (S/O/D) scoring. Our methodology is grounded in structured prompt engineering theory, utilizing scope bounding techniques to reduce hallucination while preserving extraction accuracy. Assessment against expert-validated ground truth (over 12 years of functional safety experience) across several automotive system diagrams indicates a 92% accuracy rate for signal extraction and component categorization, with S/O/D scoring obtaining an accuracy range of 70–90%. The results demonstrate substantial potential to reduce manual FMEA development processes (as compared to prior studies). Key limitations include sensitivity to diagram complexity and quality, as inadequately designed diagrams markedly affect output precision along with the inability of LLMs to create new detection measures reliably. Our Hu-IL validation process mitigates these limitations while preserving the advantages of automation. This study provides baseline performance indicators for LLM-based FMEA automation and demonstrates significant potential in transforming traditional FMEA workflows in safety-critical industries.
Due to the spot weld and mechanical fastener share the similar characteristics to join sheets together with differences in deformation behavior around joint region, a novel spot joint element (user-defined element) consists of regular Mindlin shell elements and equations for different kinematic constraints is proposed to simplify the spot joint representation in lightweight automotive structures. The novel spot joint element can not only provide accurate deformation behavior around joint region but also output mesh-insensitive structural stresses at virtual nodes with the use of traction-based structural stress method for fatigue failure analysis. In this investigation, the structural stress distributions around joint circumference in the lap-shear specimens with spot weld or fastener are first calculated to validate the accuracy of the novel spot joint element. Then, the structural stresses along different cross-sections emanating from joint are also calculated for the specimens with fasteners to investigate the potential different failure modes. Finally, the fatigue data correlation based on the novel spot joint element and traction-based structural stress method using available literature data are presented and served as example applications.
This study addresses the challenge of ensuring the durability of closed couple exhaust manifolds in the compact engine bays of modern vehicles, focusing on a longitudinally mounted 1.2L 4-cylinder engine. The original sheet metal Exhaust manifold design failed the thermal fatigue bench durability test, requiring a complete redesign to improve strength without changing materials. Initial simulation predictions significantly deviated from physical test results, with repeated cracks observed during accelerated thermal fatigue bench testing, despite simulations predicting a higher number of cycles before failure. This difference highlighted the need for a deeper understanding of the manifold's failure modes, primarily thermal fatigue, and mechanical vibration during engine transients. The design of experiment (DOE) approach was used to find the effect of different parameters e.g., gas temperature, surface temperature, air flow, thermal gradient, on the durability result & also to understand these parameters in real life vehicle driving conditions. This revealed the root causes of the cracks and established a dependable match between simulation and actual testing. The redesigned manifold included many key changes: increased wall thickness to enhance structural strength, a reshaped geometry to optimize flow and reduce stress points, and the addition of webbing in the port area to improve heat distribution and provide extra support. Furthermore, testing protocols were refined to replicate real-world driving conditions, including more precise temperature cycling. These refined protocols enabled the identification of design flaws and facilitated the validation of improvements. The final design successfully passed tough accelerated thermal fatigue bench testing, showing significantly improved durability. This research highlights the importance of accurate simulation modelling, targeted design improvements, and refined testing to replicate real world driving conditions in overcoming thermal challenges within tight engine spaces, leading to strong and durable exhaust systems.
Electric vehicles present unique challenges in electromagnetic compatibility testing due to compact packaging, high-frequency switching systems. This paper presents a systematic debugging methodology for identifying radiated emission and radiated immunity issues in these EV platforms. A comprehensive approach is outlined, covering radiated emission measurement; Bulk Current Injection based immunity simulation, and near-field probing techniques. For RI evaluation, BCI testing in the 20 to 400 MHz range is used to simulate radiated threats on the vehicle's power and signal harnesses and handy transmitter near field injections for higher frequency simulation. For RE diagnosis, conducted emission measurements on vehicle harnesses are performed using current probes to capture high-frequency currents. Additionally, near-field electric probes are used at the component to identify dominant noise sources such as DC-DC converters, Motor control unit, and improperly grounded shielding. Case studies on various EV vehicles highlight common failure modes. This practical diagnostic workflow provides an efficient toolkit for EMC engineers to accelerate compliance readiness, reduce test iterations, and enhance vehicle-level EMC performance for electric vehicles.
Puddling is a crucial process in rice cultivation, involving the preparation of the soil in a flooded field to create a soft, muddy seedbed. There are two classifications for puddling: full cage and half cage. Full cage puddling involves replacing the rear wheels of the tractor with steel paddle wheels, which are used to till the rice paddies directly without any additional implement. In the half cage puddling, the rear wheels remain on the tractor, and a smaller cage or paddle wheel is attached to the outside. Considering the field size, the operator often releases the clutch very quickly after a speed or direction change. This generates torque spikes, which are harmful to Transmission Gears and Clutches. This can lead to gear teeth bending fatigue failure due to repeated higher bending stresses. In this paper, a study related to how to reduce overall product development time by simulating bending fatigue failure of gear in lab environment is presented. A systematic approach is used to understand the field application, data acquisition, Data analysis, new test stand development and replication of failure mode in lab environment. This approach resulted in significant time savings. Multiple design iterations with minimal variation can be executed. This eliminates dependency on field, environmental conditions, and different variabilities. Finally, it supports timely decision-making based on the outcomes.
Items per page:
50
1 – 50 of 1758