Simulation Of Fracture Research Articles

Numerical Simulation of Fatigue Crack Growth and Fracture in Welded Joints Using XFEM—A Review of Case Studies

Numerical simulation of fatigue crack growth in welded joints is not well represented in the literature, especially from the point of view of material heterogeneity in a welded joint. Thus, several case studies are presented here, including some focusing on fracture, presented by two case studies of mismatched high-strength low-alloyed (HSLA) steel welded joints, with cracks in the heat affected zone (HAZ) or in weld metal (WM). For fatigue crack growth, the extended finite element method FEM (XFEM) was used, built in ABAQUS and ANSYS R19.2, as presented by four case studies, two of them without modelling different properties of the welded joint (WJ). In the first one, fatigue crack growth (FCG) in integral (welded) wing spar was simulated by XFEM to show that its path is partly along welded joints and provides a significantly longer fatigue life than riveted spars of the same geometry. In the second one, an integral skin-stringer panel, produced by means of laser beam welding (LBW), was analysed by XFEM in its usual form with stringers and additional welded clips. It was shown that the effect of the welded joint is not significant. In the remaining two papers, different zones in welded joints (base metal—BM, WM, and HAZ) were represented by different coefficients of the Paris law to simulate different resistances to FCG in the two cases; one welded joint was made of high-strength low-alloyed steel (P460NL1) and the other one of armour steel (Protac 500). Since neither ABAQUS nor ANSYS provide an option for defining different fatigue properties in different zones of the WJ, an innovative procedure was introduced and applied to simulate fatigue crack growth through different zones of the WJ and evaluate fatigue life more precisely than if the WJ is treated as a homogeneous material.

Optimization method for predicting coal reservoir fractures in the Laochang area of Eastern Yunnan using paleotectonic stress inversion

IntroductionCoal reservoir fractures serve as critical storage spaces and migration pathways for coalbed methane (CBM), significantly influencing CBM enrichment. The characteristics of coal reservoir fracture development can be obtained using traditional simulation methods, but these still have shortcomings. This work presents an optimization approach for the traditional method.MethodsThis study introduces an optimization approach for traditional methods with two novel contributions. This study integrates the simulation of tectonic stress fields with fracture prediction, using surface sandstone fractures as constraints to reconstruct the paleostress field of the coal seam, while also accounting for the influence of coal thickness on fracture development to calculate fracture density.ResultsThe predicted fracture density results were validated against measured values from the Bailongshan mine and Xiongdong coal mine with a relative error of approximately 12%, suggesting a reasonable degree of reliability.DiscussionBased on the results of the fracture simulation predictions, it is believed that the coal seam fracture density in the study area is mostly 10–20 lines/m and that the sweet spot for CBM development is located in the Yuwang block.

Condensate Banking Analysis Optimizes Reservoir Development in Permian Basin

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTeC 4044947, “Numerical Analysis of Condensate Banking and Development Optimization in the Deep Formation of the Permian Basin,” by Jichao Han, SPE, Sunil Lakshminarayanan, and Jiasen Tan, SPE, Oxy, et al. The paper has not been peer reviewed. _ In the context of unconventional reservoir development, the issue of condensate banking—a factor contributing to reduced productivity in gas condensate reservoirs when the reservoir pressure falls below the dewpoint pressure—poses a constant concern. Before implementation of any mitigation strategies, it is prudent to assess the potential of condensate banking in the future, based on the limited early production data. A specialized workflow was devised for a deep formation in the Permian Basin. This workflow aims to quantify the severity of condensate banking and subsequently optimize reservoir development strategies. Introduction Well A represents a single appraisal well situated within deep formations of the Permian Basin. With only 5 months of production data available, pressure/volume/temperature analysis and modeling identified it as a gas condensate reservoir, with the dewpoint very close to the critical point. This prompts two critical business inquiries: Are there any concerns regarding condensate banking for this well? And what are the optimal drawdown strategies tailored to this specific format surrounding the appraisal well? Model Setup and Calibration Modeling Workflow. This study uses the comprehensive simulation workflow derived from Hydraulic Fracturing Test Site 2, which can effectively handle integrated models to provide valuable insight for condensate banking analysis and reservoir development optimization (Fig. 1). Hydraulic fracture and reservoir simulations were conducted using GOHFER 3D and Navigator software, respectively. The integration of fracture and reservoir models poses a significant challenge in accurately transferring fracture geometry and conductivity information from fracture simulators to reservoir simulators. To address this challenge, an in‑house preprocessor was developed, designed to project results from the fracture simulator into the reservoir simulator seamlessly, ensuring the fidelity of complex fracture geometries. This preprocessor enables the extension or contraction of fracture geometries in proportion to reduce uncertainties imposed by production data. Additionally, fracture conductivity is determined through regional correlations among proppant concentration, net closure stress, and fracture conductivity. Model Introduction. The geological model has been simplified to enhance modeling efficiency while still meeting the project requirements. The 3D geological model adopts a layer-cake structure with a flat geostructure. To ensure accuracy, the well trajectory is adjusted to align with the desired formation. The reservoir model measures 4,000×10,000×330 ft, with a grid resolution of 200×25×10 ft. Fracture geometry is imported from the fracture simulator, while fracture conductivity is primarily determined based on proppant concentration data exported from the fracture simulator. Fracture height remains unaltered in the reservoir simulator, reflecting available geochemical measurements. A compositional simulation approach is adopted instead of a black-oil model. To improve the accuracy of pressure drop and condensate dropout predictions, the local grid refinement (LGR) approach is selected, resulting in denser grids. This approach proves superior to the dual-porosity, dual-permeability (DPDP) method.

Workflow Helps Predict Casing Deformation During Hydraulic Fracturing in Shale Gas

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTeC 4043054, “Casing-Deformation-Risk Prediction With Numerical Simulation During Hydraulic Fracturing in Deep Shale Gas Reservoirs,” by Jianfa Wu, Xuewen Shi, and Qiyong Gou, PetroChina, et al. The paper has not been peer reviewed. _ In this study, a numerical simulation workflow was established based on comprehensive modeling of a time-lapse stress field, hydraulic fracturing simulation, natural fractures, and other weak interfaces to analyze casing-deformation mechanisms of shale gas horizontal wells during the multistage hydraulic fracturing process. The authors write that they aim to guide the prediction of, and provide mitigating solutions for, casing-deformation risks while improving stimulation efficiency. Introduction The burial depth of deep shale gas reservoirs in the southern Sichuan Basin is approximately 3500 to 4500 m. These have complex geological conditions with developed faults and fractures and high in-situ horizontal stresses. During multistage hydraulic fracturing operations in horizontal wells, establishing an effective prediction method for casing-deformation risks in these reservoirs is a challenge. An integrated workflow is proposed to evaluate and predict casing-deformation risks, effectively support hydraulic fracturing operations, and reduce and mitigate casing failure in these reservoirs. Modeling Methodology It is essential to consider the effects of multiscale natural fractures when constructing a 3D stress model. Natural-fracture stability can be evaluated and used to identify unstable fractures that may cause casing failures. The fundamental workflow of predicting and preventing the casing failure is as follows: 1. Build a 3D geological model characterizing the spatial distribution and geometry of faults and natural fractures 2. Construct a 3D stress model to characterize the in-situ stress state 3. Perform numerical simulations of hydraulic fracturing and 4D coupled stress simulation to obtain the stress field during and after hydraulic fracturing 4. Quantitatively analyze the shear slip risks of natural fractures by calculating slip tolerance as an indicator to determine risk levels of casing deformation 5. Optimize and adjust engineering parameters for hydraulic fracturing to reduce and mitigate casing deformation Natural-Fracture Distribution and Model Construction. In this study, natural fractures parameters such as density, strike, inclination, length of extension, and height were obtained. The natural fractures were calibrated and verified with cores and wellbore images. Natural-fracture distribution was then validated with the expected tectonic history and present-day stress regime. In Fig. 1, the left-hand plot depicts the ant-tracking results by seismic attribute, the central plot portrays natural fractures validated by microseismic events, and the right-hand plot illustrates the 3D natural-fracture model. Results showed two major fracture strikes, one in the northeast and the other in the northwest, forming a mesh network distribution that will be used in the stress model, fracturing simulation, and slip analysis.

A coupled peridynamics–smoothed particle hydrodynamics model for fluid–structure interaction with large deformation

Fluid–structure interaction (FSI) is ubiquitous in various engineering disciplines, and effectively managing FSI often appears to be the key for successful failure analysis and safety-oriented design. Smoothed particle hydrodynamics (SPH) serves as a potent nonlocal meshfree method for fluid dynamics modeling, while peridynamics (PD) demonstrates exceptional capability in addressing structural dynamics involving large deformations and discontinuities. Thus, leveraging their respective strengths in a combined approach holds significant promise for tackling FSI challenges. In this work, we propose a new peridynamics–smoothed particle hydrodynamics (PD-SPH) coupling model for addressing FSI. A stable and efficient coupling algorithm for data transfer between PD and SPH is put forward. In this coupling strategy, a PD particle directly participates in solving the SPH governing equations when it is identified to be within the support domain of an SPH particle. This can be done since the SPH quantities including the density, velocity, and pressure of a PD particle are naturally attainable within the framework of non-ordinary state-based peridynamics theory. Concurrently, in solving PD governing equations, reaction forces from SPH particles act as external forces for PD particles, determined straightforwardly through Newton's third law. As such, the proposed PD-SPH coupling strategy is straightforward to implement and offers high computational efficiency. Validation examples demonstrate that the proposed PD-SPH coupling model is computationally robust and adept at capturing physical phenomena in diverse FSI scenarios involving breaking free surfaces of fluid and large structural deformations of solid. Moreover, the proposed PD-SPH coupling model is flexible introducing no constraint conditions for applications and can accommodate different particle resolutions for PD and SPH domains. These features enable a broad application range of the proposed PD-SPH coupling model including simulations of explosion-induced soil fragmentation, rock fracture, and concrete dam failure, which will be conducted by authors in the near future.

Reduced-order peridynamics for efficient simulation of fracture in a turbine blade root

This paper introduces an adaptive partitioned reduced-order model (ROM) of peridynamics for the efficient simulation of fracture in a gas turbine blade root. The computational domain is divided into an ROM subdomain and a full-order model (FOM) subdomain. The subdomains adaptively evolve to ensure that the FOM domain covers the fractured area. The proposed model is used to investigate the failure of a gas turbine blade root under static and fatigue loads, respectively. The simulation results coincide well with the actual fracture morphology. In addition, in the three-dimensional case, the computational efficiency can be improved by approximately 300 times

Propagation of Hydraulic Fractures and Natural Fractures: The Bypassing Behavior in 3D Space

Summary The interaction between natural fractures (NFs) and hydraulic fractures (HFs) in 3D space poses significant challenges to numerical simulation. The interaction behaviors between HFs and NFs in 3D space include crossing, offset, stopping, and bypassing. Many existing numerical simulators are 2D, which inherently limits their ability to account for the vertical growth of fractures. Consequently, they are unable to model the bypassing behavior effectively. In this paper, a mathematical model for the propagation of HFs and NFs in a naturally fractured reservoir is established. The displacement discontinuity method (DDM) is used to solve the rock deformation, while the finite difference method (FDM) is utilized to solve the fluid flow within fractures. The undirected graph structure is used to represent the complex fracture network, and a dynamic adjustment of grid connectivity method is implemented to describe the process by which HFs bypass NFs. By integrating with graphics processing unit (GPU) computing, an efficient 3D simulator for HFs and NFs propagation is developed. The accuracy is verified against analytical solutions and reference solutions. Subsequently, a series of numerical studies on the bypassing behavior are conducted. The primary findings are as follows: (1) The simulator can accurately capture the interactions between HFs and NFs in 3D space, including crossing, arresting, and bypassing behaviors. (2) The bypassing behavior is characterized by three distinct processes—intersection, height growth of HF, and bypassing. (3) During the intersection stage, both the injection pressure and maximum NF width increase. During the height growth stage, the pressure is relatively stable, while the maximum NF width continues to increase. These two stages together result in the “storage” phenomenon. Once the bypassing behavior occurs, both the pressure and the maximum NF width decrease sharply, leading to a “release” phenomenon. Additionally, the “storage” and “release” phenomena may impact proppant transport. (4) Given the presence of bypassing behavior, it is essential to consider the NFs in 3D fracture simulators. The simulator and its findings can provide valuable insights for field design.

Numerical simulation on multi-well fracturing considering multiple thin layers in vertical direction

Multiwell fracturing is a key technology for developing shale gas and shale oil reservoirs. In this study, a multiple planar 3D (PL3D) fracture simulator that can capture multiple thin layers was developed to examine the propagation of multiple fractures during multicluster fracturing in multiple horizontal wells. The simulator considers multiple thin layers in the vertical direction. The results of the model are validated against the analytical solution of a single radial fracture and the implicit level set algorithm (ILSA). Using the simulator, a series of numerical simulations based on the field case are performed to investigate the fracture propagation mechanism of multiwell fracturing. The completion sequence, well placement pattern, well spacing, and cluster spacing are investigated to optimize the treatment parameters. The effective fracture area is used to quantitatively describe the stimulation effect. The adaptability of the completion sequence and well placement pattern is also analysed from the perspective of “frac hits”. The results show that the completion sequence has a critical influence on the stimulation effect and fracture geometry. From the perspective of avoiding “frac-hit” fractures, fracturing the low-stress layer can form an “artificial stress barrier”, which slightly protects the well from interference from other fractures. The staggered well pattern is better than the stacked well pattern. Compared with the stacked pattern, the staggered pattern can reduce the overlap area of fractures by 80 %, which greatly reduces the probability of “frac-hits”. With increasing well spacing from 200 m to 500 m, the fracture area increases by 25 %, and the degree of uneven stimulation between the two pay zones also increases by 6 %. Considering that a small well spacing is prone to “frac hits”, a large well spacing leads to an unstimulated area between two wells, and a 350 m well spacing is optimal. The effective fracture area decreases slightly with increasing perforation cluster spacing, but the fracture geometry becomes much more regular. The results can be helpful for the field design of multiwell fracturing.

Interaction of propagating crack with microstructure in CGI: In situ tensile test and numerical simulation

Compacted graphite iron (CGI) is a double-phase material, in which complex graphite morphology greatly influences crack initiation and propagation. Despite its wide use and considerable past research on the fracture behaviour of CGI, the understanding of the interaction of propagating cracks with CGI's microstructure is still limited. In this study, a novel method is employed that integrates scanning electron microscopy (SEM) and an optical high-speed camera. This approach allows the clear visualisation of microstructures before and after fracture, as well as the calculation of crack-propagation rate during tensile tests. It is also revealed for the first time that in the case of graphite particles situated at a specific distance from the primary crack path, the initiation of secondary micro-cracks, near particles does not occur. A critical distance from the main crack path for crack initiation is analysed. Further, finite-element simulations are developed to study the effect of microstructure on the fracture behaviour of the tested microstructures. A Johnson-Cook (JC) damage model is calibrated and used in all simulations. The crack path and velocity of simulation results are in good agreement with the experimental data, demonstrating that the JC damage model can be used to predict the crack initiation and propagation of CGI. It is found that interface debonding and crack initiation always tend to appear near the tip of vermicular graphite. Thus, large vermicular graphite particles can affect negatively the toughness of CGI. Graphite particles situated farther from the primary crack significantly reduce the likelihood of crack initiation in that specific location. Furthermore, large nodular graphite particles absorb energy and generate secondary cracks, while small graphite particles have little effect on the crack-path direction. The newly discovered fracture mechanisms and simulation results provide new insights for the design and manufacture of metal-matrix composites (e.g., Al/SiC) with optimal mechanical properties.

Palmar Displacement in Distal Radius Fractures following Extension Injuries of the Wrist

Fractures of the distal radius have been traditionally classified based on the suspected mechanism of injury. Among clinicians, the terms "Colles" and "Smith" fractures are commonly used to refer to a distal radius fracture that is either displaced to the dorsal (Colles) or palmar (Smith) side of the radius. When analysing x-rays, it is not uncommon for a Smith fracture to be detected in cases where patients describe a fall on the wrist in an extended position. Thus, the question arises how a flexion-type fracture can occur after an extension injury. So far, only little research has been conducted into this subject. The aim of this study was to analyse the mechanisms of injury that lead to various types of distal radius fractures. Particular emphasis was placed on "Smith" fractures and on the biomechanical, physiological and anatomical characteristics that contribute to their occurrence. To assess these relationships, data of fractures were collected following a life-like fracture simulation using a "drop-bench" in non-formalin fixated human specimens. These fractures were produced between January 2016 and December 2021. Biographic data of all specimens used were available. Additionally, all biomechanical and physical characteristics of the fracture simulation were fully documented. Of the 122 specimens with a full data set, 17 (13.9%) fractures were determined to be Smith fractures based on their radiological appearance. In 10 of these flexion fractures, the wrist was set in dorsal extension. The mean angle of extension was 86.3 degrees for flexion fractures compared to 90.5 degrees for extension fractures. Six out of 10 Smith-type fractures that were set in dorsal extension were also exposed to pronation, whereas only one was exposed to supination. The mean potential energy for fracture creation was 168.0 joules for Smith fractures in dorsal extension, whereas all other fractures showed a mean of 185.2 joules. It can be concluded that a Smith fracture is not limited to being the result of a fall on the wrist in a flexed position. The same fracture may also be the result of a fall with the wrist in an extended position if certain physical factors are applicable.

Comparative Study on Artificial Fracture Modeling Schemes in Tight Reservoirs—For Enhancing the Production Efficiency of Tight Oil and Gas

In order to improve the reliability of the deployment of production schemes after artificial fracturing in tight reservoirs, it is urgent to carry out research on the description of fractures after artificial fracturing. In this study, taking the Chang 61 oil formation group in the Wangyao South area of Ordos Basin as an example, three different fracture modeling schemes are used to establish the geological model of fractured reservoirs, and the fitting ratios of the respective reservoir models are calculated by using the method of reservoir numerical simulation of the initial fitting, and the optimal fractured reservoir modeling scheme is screened in the end. The research area adopts three types of fracture prediction results based on FMI fracture interpretation data, seismic fracture prediction data, and rock mechanics artificial fracturing simulation data. On this basis, geological models of fractured reservoirs are established, respectively. The initial fitting of reservoir values of each geological model are compared, and the highest initial fitting rate of reservoir values is 88.44%, which is based on rock mechanics artificial fracturing simulation data. However, the initial fitting rate of the reservoir model was the lowest at 75.76%, which was established based on the fracture random modeling results of FMl fracture interpretation data. Under the constraints of seismic geostress prediction results and microseismic monitoring data, the simulation results of rock mechanics artificial fracturing fracture are used as the basis, on which the geological model of artificially fractured reservoirs is thus established, and this scheme can more realistically characterize the characteristics of fractured reservoirs after artificial fracturing in the study area.

Simulation of fracture and damage with Peridynamics.jl

Simulation of fracture and damage with Peridynamics.jl

Evaluating Fracture Energy Predictions Using Phase-Field and Gradient-Enhanced Damage Models for Elastomers

Abstract Recently, the phase-field method has been increasingly used for brittle fractures in soft materials like polymers, elastomers, and biological tissues. When considering finite deformations to account for the highly deformable nature of soft materials, the convergence of the phase-field method becomes challenging, especially in scenarios of unstable crack growth. To overcome these numerical difficulties, several approaches have been introduced, with artificial viscosity being the most widely utilized. This study investigates the energy release rate due to crack propagation in hyperelastic nearly-incompressible materials and compares the phase-field method and a novel gradient-enhanced damage (GED) approach. First, we simulate unstable loading scenarios using the phase-field method, which leads to convergence problems. To address these issues, we introduce artificial viscosity to stabilize the problem and analyze its impact on the energy release rate utilizing a domain J-integral approach giving quantitative measurements during crack propagation. It is observed that the measured energy released rate during crack propagation does not comply with the imposed critical energy release rate, and shows non-monotonic behavior. In the second part of the paper, we introduce a novel stretch-based GED model as an alternative to the phase-field method for modeling crack evolution in elastomers. It is demonstrated that in this method, the energy release rate can be obtained as an output of the simulation rather than as an input which could be useful in the exploration of rate-dependent responses, as one could directly impose chain-level criteria for damage initiation. We show that while this novel approach provides reasonable results for fracture simulations, it still suffers from some numerical issues that strain-based GED formulations are known to be susceptible to.

High strain-rate fracture behavior of a hollow projectile

In this paper, a hollow projectile made of AISI4340 steel was fabricated based on an arbitrary warhead shape, and high-speed impact tests were performed according to various target encounter conditions including velocity and angle. In order to characterize the dynamic fracture behavior, tensile tests were performed on various notch specimens under three strain rates (10–3 s-1, 100 s-1, 103 s-1), and the stress state histories of the specimens were calibrated through a hybrid experimental-numerical analysis. In particular, for the intermediate (100 s-1) and high (103 s-1) strain rate conditions, the local temperature rose due to adiabatic heating until fracture was experimentally measured, and the thermal softening behavior determined from the inverse optimization technique was considered for the dynamic constitutive model. For the comparison with the high-speed impact test results, a rate-dependent ductile fracture model was utilized for numerical simulation. Considering that the model parameters were calibrated with the thermal softening effect, the proposed fracture model implicitly takes temperature into account. The deformation and fracture modes of the projectile from experimental and numerical study showed very good agreement under all impact conditions. It was confirmed that the softening of a material by adiabatic heating should be considered along with strain rate hardening in dynamic fracture simulation.

Fracture simulation of fiber reinforced composite panels with holes

Fiber reinforced composite (FRC) with holes have broad applications in various fields. In this study, the influence of fiber orientation and hole distribution on the fracture behavior of FRC was investigated. A phase-field modeling was established to simulate the fracture process of the composite, and the mechanical performance of unidirectional fiber reinforced composite and woven fiber reinforced composite were analyzed, respectively. Our numerical results showed that fiber orientation and hole distribution have a significant impact on the fracture behavior of FRC. We observed that aligning the fibers parallel to the loading direction led to an increase in the maximum load bearing capacity of the composite. A more uniform hole distribution can enhance the overall mechanical performance of FRC. Furthermore, in the presence of thermal shock, crack propagation tends to grow towards the hole. These findings are of great significance for understanding the fracture behavior of FRC, and for optimizing material design and fabrication processes.

An anisotropic eigenfracture approach accounting for mixed fracture modes in wooden structures by the Representative Crack Element framework

Finite Element analysis of anisotropic fracture phenomena in wood is a challenging task, particularly when dealing with intricate loading scenarios and mode-specific behavior. The appeal of energetically motivated approaches, such as the eigenfracture method, is that they enable simulation of fracture without prior knowledge of the crack path. The promising eigenfracture method has shown good numerical performance for isotropic materials, and this contribution showcases its application to anisotropic materials. Wood is one such anisotropic material and in this manuscript, the directional dependence of both elasticity and fracture evolution are incorporated into the eigenfracture approach. Further, the eigenfracture approach is used in conjunction with Representative Crack Elements (RCE), which permit accurate modeling of physical crack deformations. The governing equations are systematically derived and implemented into the Finite Element framework. By representative numerical examples, some advantages over the alternative phase-field method are demonstrated. Another highlight of this work is that it is possible to provide a realistic ratio of the energy release rates parallel to and perpendicular to the fiber direction in order to achieve physically accurate crack patterns. Additionally, the calculation effort is reduced, because the unknowns required to determine the crack kinematics can be solved analytically at the material level, a feature that also enables parallelization.

Local heating at the running crack tip in bcc iron according to molecular dynamics

Abstract This study presents estimates of a possible temperature rise at the crack tip from three dimensional (3D) atomistic simulations of fracture via molecular dynamics (MD) technique. Simulations start from an initial temperature of 0 K. The pre-existing edge crack was loaded in tension mode I. Crack initiation in MD is accompanied by surface dislocation emissions and later by a cross slip of the emitted dislocations into other slip systems. This leads both to stress waves radiation and to local heating in the plastic zone created by these dislocations. The local heating at the crack tip in the surface layers reaches a level of 480–500 K at some atoms, but an average temperature in the plastic zone is lower and depends on a chosen crack tip zone size. In the bulk crystal, where no dislocation emission (i.e. no plastic zone) has been realized, no significant heating is observed at the crack tip. MD results at the free sample surface comply with experimental data for ferritic steels with a pre-existing notch, loaded (quasi-statically) in mode I, as well as with some continuum predictions.

Athletic Trainer Emergency Management Skill Assessment via Low Fidelity Simulation Authors

Introduction: Athletic training education requires the inclusion of emergency management (EM) best practices, however the Board of Certification (BOC) does not mandate any continuing education (CE) past Emergency Cardiac Care (ECC). With EM best practices continuing to change there is potential for a large knowledge gap to develop in practicing athletic trainers (ATs) who do not chose to engage in EM CE. The purpose of this study was to identify knowledge gaps in practicing ATs’ EM skills via low fidelity simulation. Methods: A cross-sectional study was conducted in an educational laboratory setting involving twenty-two ATs (age 36.7±10.8 years; 13 males, 9 females, years of experience 13 + 11) attending a simulation-based CE event. A convenience sample of participants who attended the CE event voluntarily participated in data collection. Upon the completion of an educational review session, participants completed four low fidelity simulations (elbow dislocation, femur fracture, heat stroke and external hemorrhage) based on the 2020 Commission on Accreditation of Athletic Training Education (CAATE) standards. Checklists (completed/not completed) were utilized to grade participants simulation specific skill application. Mean overall, critical action, SAMPLE and vital scores were analyzed. Scores were calculated as percentages in order to compare the low fidelity simulation outcomes. A benchmark of 80% skill application was utilized for a successful pass rate. Results: The only benchmark achieved was the critical action score within the femur fracture simulation (82.89% ±14.56). A success rate of 9.6% (8/83) was calculated across all simulations. The mean total percent scores were as follows; elbow dislocation 65.0 ± 11.0, femur fracture 55.3 ±10.0, heatstroke 67.7 ±17.5 and external hemorrhage 64.0 ±13.0. All means beyond the critical action femur, were below the benchmark of 80%. Conclusions: A knowledge gap exists between practicing clinicians and the 2020 CAATE EM standards. Considering the importance of ATs lifesaving skills, ATs should aim to choose CE to improve their EM skills. While this study only investigates EM, ATs may demonstrate knowledge gaps in other domains and therefore ATs should aim to diversify their CE to stay current with best practices.

Advanced Computational Methods for Simulating and Optimizing Stochastic Fracture: A Systematic Literature Review

Stochastic fracture processes, pervasive in diverse natural and engineered systems, pose intricate challenges for accurate simulation and optimization. This systematic literature review surveys the landscape of advanced computational methodologies to unravel and optimize stochastic fracture phenomena. Grounded in multidisciplinary perspectives spanning engineering, physics, and applied mathematics, the review navigates through the intricacies of simulation techniques and optimizations methods. From Finite Element Method (FEM) to Molecular Dynamics (MD) simulations, the review delineates the evolution and application of computational frameworks. It scrutinizes optimization strategies ranging from evolutionary algorithms to surrogate-assisted techniques, illuminating their efficacy in optimizing fracture properties amidst stochasticity. Drawing from applications in geological formations, engineered materials, and biomechanics, the review elucidates the diverse realms where advanced computational methods find resonance. Despite strides in computational prowess, challenges loom large, including computational complexity, validation dilemmas, and interdisciplinary communication barriers. Looking ahead, the review prognosticates on the integration of machine learning, novel algorithmic developments, and standardization endeavor’s to propel the frontier of stochastic fracture simulations towards unprecedented realms of understanding and optimization. Through synthesis and critique, this review engenders a roadmap for future research and underscores the transformative potential of advanced computational methods in deciphering stochastic fracture phenomena.

A novel semi-explicit numerical algorithm for efficient 3D phase field modelling of quasi-brittle fracture

Phase field models have become an effective tool for predicting complex crack configurations including initiation, propagation, branching, intersecting and merging. However, several computational issues have hindered their utilisation in engineering practice, such as the convergence challenge in implicit algorithms, numerical stability issues in explicit methods and significant computational costs. Aiming to providing a more efficient numerical algorithm, this work integrates the explicit integral operator with the recently developed neighbored element method, for the first time, to solve the coupled governing equations in phase field models. In addition, the damage irreversibility can be ensured automatically, avoiding the need to introduce extra history variable for the maximum driving force in traditional algorithms. Six representative fracture benchmarks with different failure modes are simulated to verify the effectiveness of the proposed method, including the multiple cracks in heterogeneous concrete at mesoscale. It is found that this semi-explicit numerical algorithm yields consistent crack profiles and load capacities for all examples to the available experimental data and literature. In particular, the computational cost is significantly reduced when compared to the traditional explicit modelling. Therefore, the presented numerical algorithm is highly attractive and promising for phase-field simulations of complicated 3D solid fractures in structural-level engineering practices.