Analysis Of Propagation Research Articles

A Survey of Function Failure Identification and Propagation Analysis Methods for System Design

Abstract In the context of model-based product and system design, the capability to assess the impact of potential component faults, undesired interactions, and fault propagation is important for design decision-making. Addressing these potential negative outcomes should occur as early in the design process as possible to enable designers to make impactful changes to the design. To this end, a set of tools and methods have been developed over the last 20 years that leverage a function-based approach assessing the potential faults and fault propagation and develop system health management strategies. These tools and methods must overcome challenges of high abstraction and satisfaction of safety or risk requirements with limited design specification. This paper provides a detailed survey of a particular function-based analysis tool as a lens to understanding the challenges for other tools in this domain. Specifically, development and evolution of the Function Failure Identification and Propagation Framework (FFIP) is used as a lens to survey the challenges of this field. The objective of this paper is to explore the specific challenges and advancements of the FFIP framework and related tools that address similar modeling and analysis challenges. We provide an overall categorization and summary of the research efforts to date and identify specific known limitations and unaddressed challenges in the area of design-stage system risk and safety analysis.

Research on the upper limit of constant strain rates and dynamic fracture behavior for hybrid woven composite

Based on the analysis of stress wave propagation at both ends of the specimen, a formula for the upper limit of the constant strain rate is derived. The upper limit of constant strain rate is applicable to all the ratios of wave impedance, providing a broader applicability. The in-plane dynamic compressive behavior was obtained for 2D plain weave carbon/aramid hybrid composites at strain rates ranging from 195 to 790 s−1. The results validate the prediction of the upper limit of the constant strain rate. The strength exhibited sensitive to strain rate. A nonlinear constitutive model described the dynamic constitutive relationship effectively under different strain rates. The distribution of delamination failure significantly influenced the final failure shape of the specimens. Microscopic observations indicated that carbon fiber yarns and aramid fiber yarns exhibited different fracture modes.

Analysis of shock wave propagation in two-layered blood flow model via Lie symmetry

In this paper, we study the two-layered blood flow model within the framework of Lie symmetry analysis to investigate a range of closed-form solutions. Our investigation involves optimal classification, revealing the existence of six optimal subalgebras within the model. Further, we streamline the model by reducing it into a system of ordinary differential equations (ODEs), thereby deriving several exact solutions. Our analysis establishes the presence of the nonlinear self-adjointness property in the governing equation, leading to the development of various conservation laws. Furthermore, leveraging one of the exact solutions we obtained, we delve into the behaviour of characteristic shocks, C1 waves, and their interactions, providing a comprehensive understanding of their dynamics.

Polarization-resolved near-field characterization of coupling between a bus waveguide and a ring resonator

Light propagation in Photonic integrated circuits (PICs), which can nowadays involve complex systems of light-guiding structures, is measured with different approaches(Nuzhdin et al., 2020, Lončar et al., 2002, Hopman et al., 2007, Morichetti et al., 2014, Sapienza et al., 2012, Vesseur et al., 2007). An interferometric polarization-sensitive measurement of the evanescent fields of these structures provides insight in the performance of the circuit detects possible malfunction with sub-wavelength precision(Engelen et al., 2007, Gersen et al., 2005, Barwick et al., 2009). We demonstrate a Near-field scanning optical microscopy (NSOM) measurement on coupled ring resonators that shows how the guided modes evolve as they propagate across the optical chip. Analysis of the measurements provides information about intensity distribution of the two polarization components (TE and TM) and their spatial confinement. The data validates our methodology and opens new possibilities for analysis of signal propagation in prototyping and optimization of integrated optical systems. Direct observation of polarization state of the guided modes allows for clear understanding of mode conversion in coupling systems.

Propagation Analysis of an RFID System in the UHF Band in the Honeycomb Frame of a Beehive.

In recent years, communication systems, including RFID, have been used in intelligent beehives for beekeeping. RFID systems in the UHF frequency band offer reading distances of tens of centimetres, allowing the localisation and identification of the queen bee inside the hive. With this purpose, this work proposes an analysis of an environment of propagation that consists of a honeycomb frame, where the reader is placed within the frame, and the tag is placed in different positions over it. A honeycomb frame consists of a wooden box containing a honey wax panel, supported by metallic wires. The environment is modelled theoretically using its S-parameters and simulated in CST Studio. An analysis of these results and empirical measurements is performed. The results show that a periodicity in the received power of the tag is found with respect to the distance to the reader when the tag is located in a direction parallel to the wire, where local maximum and minimum values are found. Additionally, when the tag is placed over a wire of the frame, a higher received power is obtained compared to the case where the tag is placed between two wires. Furthermore, it has been observed that the reading range has increased with respect to free space, covering the full frame.

Digital fatigue cracking test and fatigue life assessment of rib-deck joints in orthotropic steel decks

The orthotropic steel decks (OSDs) are vulnerable to fatigue fractures, which will inevitably impair the normal service of the steel bridge panels. To determine the impact of the initial cracks on the fatigue life, this study constructed an evaluation model of the OSD rib-to-deck joints crack based on the fracture mechanics principle. And combined it with the multi-scale finite element analysis model, the digital fatigue test model of the whole bridge was established. Research shows: A typical I-II-III composite crack with the supremacy of type I crack can be seen in the OSD rib-to-deck joints. Fatigue cracks developed at the deck weld toe dominate the fatigue failure mode. Further research revealed that as the depth of cracks increased, the stress on the cross-section was redistributed. The intensity factor then displayed a trend of growing and then gradually flattening or even dropping. Based on the relationship between cracks of different depths and the remaining life of the OSDs, recommendations are given for bridge maintenance. The multi-scale digital fatigue test can provide analysis and simulation methods for the fatigue crack propagation in the steel bridge deck of the bridge in operation.

Analytical solution for forced vibration response of rectangular thin plates attached by straight and curved acoustic black hole beams based on symplectic and impedance method

In recent years, due to the excellent vibration reduction performance of the acoustic black hole (ABH), its application in engineering has become increasingly widespread. This paper proposes an analytical method which combines the symplectic method with the impedance method, for solving the forced response of the rectangular thin plates attached by the straight and curved ABH beams. The ABH beams and plate are connected by a short bar. Firstly, the impedance method is used to obtain the dynamic stiffness of the coupling end of the ABH beam. Secondly, the symplectic method is used to obtain analytical waves of the plates. By utilizing the relationship between force and displacement at plate-beam junction, the dynamic stiffness of the plate at the coupling point can be obtained. Finally, based on wave propagation analysis, the forced vibration response of the hybrid system are obtained. The numerical examples compared the calculation results of this method with the finite element method. The results show that the proposed method can effectively predict the forced response of the hybrid system considered in this paper. Then, the influence of the relative position between the coupling point and the excitation point on the vibration reduction effect was analyzed. This method is analytical, with accurate results and high computational efficiency.

Progressive Damage and Crack Propagation Analysis of Composite-Patched Aluminum Plate with 3D Inclined Crack under Fatigue Loading

Progressive Damage and Crack Propagation Analysis of Composite-Patched Aluminum Plate with 3D Inclined Crack under Fatigue Loading

Interfacial stress and crack propagation experimental study in mini-LED chip debonding

The ultra-miniaturization trend of chips presents new challenges for non-destructive peeling-off techniques. This study models the mini-LED chip-UV film adhesive system as a micro laminated structure and conducts the interfacial stresses and crack propagation analysis of the structure using theoretical, finite element and experimental methods. The innovations of this paper are the illustration of the negligible effect of size effect on 125 μm x 75 μm x 60 μm chips, and the determination of the technology parameter tuning method to promote chip peeling-off. Firstly, applying the first-order shear deformation theory, and considering the UV-curable acrylic adhesive layer and the UV film as elastic materials, Lamé coefficients are introduced to explore the free vibration of the micro laminated structure. The analyses indicate that the scale effect has an extremely small impact, within 0.5%, on natural frequencies of the 100-micron scale laminated structure with a small length-to-thickness ratio. Thereafter, a three parameter elastic foundation (3-PEF) model of the chip-UV film adhesive structure is established and the interfacial stresses distributions are parametrically analyzed. Additionally, an experimental platform for needle-ejecting chip peeling-off is designed and constructed. Finite element simulation, experimental observations, and image recognition of crack generation and propagation during the peeling process were performed. Results show that cracks are generated at both free ends of the adhesive layer and progressively extended inwards. This is consistent with the 3-PEF analytical solution, in which the stress concentration also occurs at free ends of the adhesive layer. The agreement between theoretical, simulation and experimental results regarding interfacial stresses provides a solid foundation for further analysis of chip peeling-off mechanism.

Impacts of water regulation through a reservoir on drought dynamics and propagation in the Pilica River watershed

Study regionThe Pilica River watershed, located in central Poland, is the largest left tributary of the Vistula River basin. Study focusThe study aims to assess the impact of human activities on drought dynamics by considering the specific role of the Sulejów Reservoir. Identifying factors contributing to drought development is essential for decision-makers to implement appropriate management measures. The temporal overlap method is used to distinguish between climate and human-driven droughts. The changes in drought propagation are assessed using the time shift method at various accumulation time scales. To assess the spatial distribution of drought, we applied the Soil and Water Assessment Tool (SWAT) model to simulate soil moisture and streamflow response at a spatial scale. New hydrological insights for the regionThe findings highlight that about 75% of meteorological droughts lead to soil moisture droughts, and about 70% result in hydrological droughts. The results show the contribution of human activities to soil moisture drought (∼25%) and hydrological drought (∼10%), indicating that not all droughts are driven by meteorological factors alone. The key finding suggests a shorter and longer time scale of around 3 and 12 months for soil moisture drought and hydrological drought propagation analysis, respectively. Moreover, the decrease in the duration and severity of drought during 2005–2019 compared to 1997–2004 suggests that the magnitude of the reservoir impact depends on its purpose and operational strategies.

An eigenvalue stabilization technique for immersed boundary finite element methods in explicit dynamics

The application of immersed boundary methods in static analyses is often impeded by poorly cut elements (small cut elements problem), leading to ill-conditioned linear systems of equations and stability problems. While these concerns may not be paramount in explicit dynamics, a substantial reduction in the critical time step size based on the smallest volume fraction χ of a cut element is observed. This reduction can be so drastic that it renders explicit time integration schemes impractical. To tackle this challenge, we propose the use of a dedicated eigenvalue stabilization (EVS) technique.The EVS-technique serves a dual purpose. Beyond merely improving the condition number of system matrices, it plays a pivotal role in extending the critical time increment, effectively broadening the stability region in explicit dynamics. As a result, our approach enables robust and efficient analyses of high-frequency transient problems using immersed boundary methods. A key advantage of the stabilization method lies in the fact that only element-level operations are required.This is accomplished by computing all eigenvalues of the element matrices and subsequently introducing a stabilization term that mitigates the adverse effects of cutting. Notably, the stabilization of the mass matrix Mc of cut elements – especially for high polynomial orders p of the shape functions – leads to a significant raise in the critical time step size Δtcr.To demonstrate the efficiency of our technique, we present two specifically selected dynamic benchmark examples related to wave propagation analysis, where an explicit time integration scheme must be employed to leverage the increase in the critical time step size.

Analysis of nonlinear wave propagation within architected materials consisting of nonlinear Timoshenko beam structural elements

In the present work, a full nonlinear Timoshenko beam employing nonlinear shape functions is developed. The extended Hamilton principle is employed for deriving the differential equations of motion and the associated boundary conditions. The general form of the boundary conditions is then utilized to determine the static solution of the beam motion. Using this solution for the deformation and rotation of the beam, the nonlinear shape functions of the beam are identified, which leads to the linear and nonlinear mass and stiffness matrices of the Timoshenko beam element. The nonlinear dispersion diagram incorporating the non-linear corrections is obtained using the Linstedt–Poincaré perturbation method. An analysis of the effect of internal transverse shear and bending on the nonlinear dispersion characteristics of wave propagation in two-dimensional periodic network materials made of nonlinear Timoshenko beams is done. The formulated theory shows that the percentage of correction factor of the nonlinear kinematics versus the linear dynamical behavior is inversely proportional to the frequency amplitude. The shear and extension modes are shown to have the higher effect in the non-linear correction term in comparison to the flexural mode.

Multi-crack propagation analysis of double-side welded rib-to-deck joint in orthotropic steel decks

Rib-to-deck welded joints are among the most susceptible to fatigue in orthotropic bridge decks (OSDs). Prior research has primarily examined the stress intensity factor (SIF) and propagation morphology of a solitary fracture at these joints, allocating limited attention to the investigation of the propagation of multiple cracks. This paper presents a methodology for simulating and computing the weld toe magnification factor and the SIF of semi-elliptical surface cracks in innovative double-sided welded rib-to-deck (DWRTD) joints. The intention was to simplify the calculation of the SIF for this fatigue detail. The SIF obtained from the calculation model in combination with a multiple crack coalescence approach resulted in a series of fatigue life prediction models of multiple co-planar semi-elliptical cracks. Compared with the results of fatigue tests on the DWRTD joints, the calculated fatigue life and propagation morphology of multiple cracks from the model showed good agreement. Finally, the parameters were analysed to investigate the effects of crack number, bridge deck thickness, residual stress, and penetration rate. Compared to a single crack, multiple cracks reduced the service life of the bridge deck by approximately 30%. When the bridge deck thickness increases from 12 mm to 20 mm, the nominal stress amplitude near the weld ∆σ decreases by 2.2 times, resulting in a 7-fold increase in crack propagation time. Compared to penetration rate and residual stress, ∆σ is the most crucial factor affecting fatigue propagation life. Therefore, it is suggested to increase the thickness of the bridge deck during design.

Analysis of crack propagation and hydraulic fracturing behavior of coral reef limestone

Analysis of crack propagation and hydraulic fracturing behavior of coral reef limestone

Non-Integer Dimensional Analysis of Ultrasonic Wave Propagation in Fractal Porous Media

This paper explores the acoustics of porous media characterized by fractal, or self-similar, structures. Employing a fractal approach, we use differential operators in non-integer dimensional spaces to address the fundamental equations of acoustics in such media. The primary aim is to examine the transmission of ultrasonic waves within a fractal porous medium. Our findings reveal that the fractal dimension significantly influences wave transmission. In fractal porous materials, waves travel along more complex and intricate paths, resulting in increased tortuosity and attenuation. We introduce the concept of an effective path length leff , which is dependent on the fractal dimension Dx , to describe the actual trajectory of wave propagation. Additionally, we define an effective tortuosity αDx , directly proportional to leff2 , to quantify the additional tortuosity brought about by the fractal structure. The insights gained from this study are crucial, as they enhance our understanding of wave behavior in self-similar porous media, which are prevalent in various natural settings and have multiple practical applications, including sound insulation and the design of acoustic materials. Furthermore, understanding the impact of fractal dimensions on wave behavior is vital for developing more efficient acoustic solutions. This research also sets the stage for further theoretical and experimental work on applying fractal geometry to analyze wave propagation in porous structures.

Computational analysis of the anode-directed streamers propagation in atmospheric pressure C4F7N/N2 mixtures

In recent years, interest in synthetic C4F7N as a gas insulator has been growing due to its unique insulation properties and low global warming potential. In spite of this, very few studies are devoted to the analysis of the electric breakdown of C4F7N and its mixtures with other dilutants such as CO2 and N2. In the present paper, we use a two-dimensional fluid model to analyze the electrical breakdown of the atmospheric pressure C4F7N/N2 mixture. We establish the influence of the C4F7N fraction in the mixture and the cathode voltage rise rate on the breakdown voltage. We find that the ratio between the electron attachment frequency and the voltage rise rate defines the streamer parameters. Namely, if the time scale of electron attachment to C4F7N is much faster than the voltage rise rate, the plasma electronegativity of the streamer body and of its head is extremely high, and it is difficult to define exactly the streamer head location. In the opposite case of the fast rise rates, the conventional streamers with sharp heads were obtained.

Numerical analysis of hydraulic fracture propagation in deep shale reservoir with different injection strategies

Deep shale reservoirs are characterized by elevated breakdown pressures, diminished fracture complexity, and reduced modified volumes compared to medium and shallow reservoirs. Therefore, it is urgent to investigate particular injection strategies that can optimize breakdown pressure and fracturing efficiency to address the increasing demands for deep shale reservoir stimulation. In this study, the efficiency of various stimulation strategies, including multi-cluster simultaneous fracturing, modified alternating fracturing, alternating shut-in fracturing, and cyclic alternating fracturing, was evaluated. Subsequently, the sensitivity of factors such as the cycle index, shut-in time, cluster spacing, and horizontal permeability was investigated. Additionally, the flow distribution effect within the wellbore was discussed. The results indicate that relative to multi-cluster simultaneous fracturing, modified alternating fracturing exhibits reduced susceptibility to the stress shadow effect, which results in earlier breakdown, extended hydraulic fracture lengths, and more consistent propagation despite an increase in breakdown pressure. The alternating shut-in fracturing benefits the increase of fracture length, which is closely related to the shut-in time. Furthermore, cyclic alternating fracturing markedly lowers breakdown pressure and contributes to uniform fracture propagation, in which the cycle count plays an important role. Modified alternating fracturing demonstrates insensitivity to variations in cluster spacing, whereas horizontal permeability is a critical factor affecting fracture length. The wellbore effect restrains the accumulation of pressure and flow near the perforation, delaying the initiation of hydraulic fractures. The simulation results can provide valuable numerical insights for optimizing injection strategies for deep shale hydraulic fracturing.

Levelized cost of electricity in renewable energy communities: Uncertainty propagation analysis

Renewable Energy Communities (RECs) are being deployed all around the World as a technically feasible solution to decreasing users' dependence on fossil fuels. Several demonstration facilities have shown their potential to provide final consumers with clean energy and all associated environmental benefits. However, the economic evaluation of these systems as a whole set is more complex than evaluating generation technologies individually, which can be considered a barrier, and it may be more complicated to calculate its uncertainty with precision. This paper deals with this challenge and adapts a model for the evaluation of the global Levelized Cost of Electricity (LCOE) of a polygeneration microgrid to the characteristics of a typical REC, allowing the assessment of the distribution of the LCOE depending on the uncertainty of the input parameters. Thanks to its simple analytical formulation, the proposed model, that can be used for any combination of technologies (both renewable and conventional), provides relevant information on uncertainty propagation in a symbolic way that avoids the need to run numerical simulations or make assumptions on the distribution of the random input parameters. A case study has been presented, considering a typical small electrical REC with photovoltaic plants and micro wind turbines. Although the model can be defined to any market, as a representative example, it has been evaluated according to the current Spanish and Italian regulations, which are analyzed in depth with reference to the scientific literature. Results show that uncertainties in parameter estimates give rise to a very large scatter in the LCOE, pointing out a set of quantities whose role is crucial for a reliable estimate, among which electricity purchase and selling prices, yearly power load, and self-consumption / virtually-shared energy rates stand out.

A numerical analysis of multi-dimensional iron flame propagation using boundary-layer resolved simulations

Iron combustion is emerging as a topic of immediate interest, given the need for the decarbonization of heat and power generation. Opposite to other solid fuels, iron particles burn predominantly in a non-volatile, heterogeneous combustion mode. For iron dust flames, two modes of flame propagation have been observed i.e. the discrete mode, when the heat transfer time scale is larger than the particle burn-time, and the continuous mode, when the heat transfer timescale is smaller than the burn-time of a single particle. The flame speed of such a flame primarily depends on the heat and mass transfer which is characterized by the distance between the particles for a dispersed mixture. Depending on the variation in particle distance and local distribution, planar or curved flames can form and propagate. The characteristics of flame propagation motivate this study and for the first time, three-dimensional particle boundary layer resolved simulations are used to analyse the effect of curvature and variable particle distances on iron–air flame propagation. Simulations are carried out for (1) planar flame propagation with constant particle spacing in the direction of propagation, and (2) curved flame propagation with varying particle spacing in the direction of propagation. The analysis of the flame speed for the planar flame propagation later guides the analysis of curved flames propagating through 900 boundary-layer resolved particles distributed in a 30 by 30 grid. The curved flame propagates with a uniform but decreased flame speed compared to the planar flame propagation with equivalent particle spacing. It is shown that positive curvature decreases the heat transfer from the burnt to the unburnt side while a variable spatial arrangement of particles allows for a local re-distribution of oxygen which causes some regions to burn richer or leaner than the corresponding planar flames with similar particle spacing.

Analysis of the Propagation of Temperature and Thermal Conductivity of Sawdust Pyrolysis Process with Modeling Fea and Experiment

The study uses densified sawdust with heat propagation and thermal conductivity to achieve better pyrolysis and gasification processes. Analysis of sawdust's heat propagation and thermal conductivity during pyrolysis was developed with Finite Element Analysis (FEA). The thermal conductivity values of sawdust (k) obtained from FEA are 1.49, 1.3, 1.1, and 0.7 W/m C considering the sawdust heated with a triggering temperature (T0) 535 ºC and reaches a constant temperature of T1 = 265 ºC, T2 = 165 ºC, T3 = 115, and T4 = 95 ºC respectively after 20 minutes. The temperature distribution of sawdust heated shows between the experimental and FEA results is quite the same; however, differences on graph T1 show the experimental thermal conductivity (k) value is distinct from the simulated thermal conductivity (k) value due to a significant change that occurred as sawdust transformed into charcoal at minute 70, where the distance between point T1 and the trigger point (T0) is 40mm and after 180 minutes the sawdust had turned into charcoal completely. Furthermore, 31 grams (6.46%) of sawdust underwent pyrolysis in this experiment. The findings can aid future research and development in this field and provide valuable insight into the duration of time a bio stove utilizing compacted sawdust can produce a sustainable flame and be used as a reference for future experiments.