bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Local Ductile Failure Assessment Method and Its Application to Four Alloys—Part II: Incorporation of the Effect of Lode Angle
Authors: Takahashi Yukio , Shigeyama Haruhisa 
Published: January 2025

Abstract
In order to guarantee the presence of adequate margin against ultimate fracture, it is essential to establish a reliable methodology for estimating ductile fracture behavior of structures. Following the development of equations for describing true stress–strain relation and their application to notched bar and grooved plate specimens made of four materials used in nuclear power plants without or with the effects of damage depending on stress triaxiality factor, incorporation of the effect of the Lode angle was explored for improving the consistency with the test results. Dependency of true rupture strain on the Lode angle as well as on the stress triaxiality factor was introduced in the new approach. Damage calculated by summing a ratio of equivalent plastic strain increment to the true rupture strain was used for determining failure point and reduction of preceding deformation resistance. Furthermore the effect of the Lode angle on the resistance against plastic deformation was introduced in a separate way to address some situation. After examining the behavior of these parameters in each specimen type, related material constants for each combination of material and temperature were determined by iterating calculations with different constants and comparisons of predicted load–displacement relations with experimental ones. Although constants needed to be adjusted according to materials and temperatures, reasonable agreements were achieved eventually between the experimental and predicted load–displacement curves for all the specimen types investigated. In particular, the maximum load and the displacement at failure could be predicted within an error of about 5% and 10%, respectively, providing compelling evidence for the soundness of the approach.
Multiscale Finite Element Modeling of Human Ear for Acoustic Wave Transmission Into Cochlea and Hair Cells Fatigue Failure
Authors: Jiang Yijie , Bradshaw John J. , Sharma Roshan , Gan Rong Z. 
Published: January 2025

Abstract
Hearing loss is highly related to acoustic injuries and mechanical damage of ear tissues. The mechanical responses and failures of ear tissues are difficult to measure experimentally, especially cochlear hair cells within the organ of Corti (OC) at microscale. Finite element (FE) modeling has become an important tool for simulating acoustic wave transmission and studying cochlear mechanics. This study harnessed a multiscale FE model to investigate the mechanical behaviors of ear tissues in response to acoustic wave and developed a fatigue mechanical model to describe the outer hair cells (OHCs) failure. A three-dimensional (3D) multiscale FE model consisting of a macroscale model of the ear canal, middle ear, and three-chambered cochlea and a microscale OC model on a representative basilar membrane section, including the hair cells, membranes, and supporting cells, was established. Harmonic acoustic mode was used in the FE model for simulating various acoustic pressures and frequencies. The cochlear basilar membrane and the cochlear pressure induced by acoustic pressures were derived from the macroscale model and used as inputs for microscale OC model. The OC model identified the stress and strain concentrations in the reticular lamina (RL) at the root of stereocilia hair bundles and in the Deiter’s cells at the connecting ends with OHCs, indicating the potential mechanical damage sites. OHCs were under cyclic loading and the alternating stress was quantified by the FE model. A fatigue mechanism for OHCs was established based on the modeling results and experimental data. This mechanism would be used for predicting fatigue failure and the resulting hearing loss.
Influence of Geometric Parameters on the Hemodynamic Characteristics of the Vertebral Artery
Authors: Chen Yanlu , Cheng Yuzhou , Luo Kun , Fan Jianren 
Published: January 2025

Abstract
The carotid arteries (CAs) and vertebral arteries (VAs) are principal conduits for cerebral blood supply and are common sites for atherosclerotic plaque formation. To date, there has been extensive clinical and hemodynamic reporting on carotid arteries; however, studies focusing on the hemodynamic characteristics of the VA are notably scarce. This article presents a systematic analysis of the impact of VA diameter and the angle of divergence from the subclavian artery (SA) on hemodynamic properties, facilitated by the construction of an idealized VA geometric model. Research indicates that the increase in the diameter of the VA is associated with a corresponding increase in the complexity of the vortex structures at the bifurcation with the SA. When the VA diameter is constant, a 30 deg VA–SA angle yields better hemodynamic capacity than 45 deg and 60 deg angles, and the patterns of blood flow and helicity values are consistent across different angles. Elevated oscillatory shear index (OSI) zones are mainly at the origin of the VA, with an elliptical low OSI region within. As the diameter increases, the high OSI region spreads downstream. Increasing the bifurcation angle decreases OSI values in and below the elliptical low OSI region. These findings are valuable for studying the physiological and pathological mechanisms of VA atherosclerosis.
A Nodal-Lie-Group Beam Element for Absolute Nodal Coordinate Formulations
Authors: Zhang Binghua , Fan Wei , Ren Hui 
Published: January 2025

Abstract
A new 12DOF beam element is proposed to simulate large deformation and large rotation based on the 24DOF absolute nodal coordinate formulation (ANCF) beam element proposed before. The centerline of the beam is interpolated by Hermite shape functions, and the frame of the beam is interpolated by linear shape functions. To reduce DOFs, the Lie-group method is used to normalize and orthogonalize the frame on each node of the beam. This way of using the Lie-group method keeps a linear relationship between the nodal vectors and shape functions and leads to the constant mass matrix and elastic tensors. Therefore, the generalized elastic and inertial forces do not require Gaussian integration at each time-step. To avoid singularity of the rotation, a relative rotation vector is adopted; correspondingly, the generalized-α integrator based on the Lie group is used to solve the dynamic equations. To improve the convergency speed and alleviate the shear locking and Poisson locking problems of this element, the assumed natural strain (ANS) method is adopted. To improve the calculational accuracy of axis stretching and torsion effects, the enhanced assumed strain (EAS) method is adopted. The formulas presented in this paper have been successfully tested in several static and dynamic examples of other ANCF beam elements and analytic solutions.
Modal Analysis for Localization in Multiple Nonlinear Tuned Mass Dampers Installed on a Structure
Authors: Harata Yuji , Ikeda Takashi , Matsuura Shuma 
Published: January 2025

Abstract
Localization may occur in systems where multiple nonlinear units are coupled with each other. Additionally, localization may occur in multiple nonlinear tuned mass dampers (TMDs) installed on a structure subjected to harmonic excitation. This paper clarifies the cause of localization via modal analysis. First, the equations of motion for a structure with multiple nonlinear TMDs, which are expressed in physical coordinates, are transformed to equations in modal coordinates. When identical TMDs are used, the lowest and highest modes are decoupled in the linear terms to the other modes; however, all these modes are nonlinearly coupled with each other. In addition, the lowest and highest modes are directly excited by an external force, but the other modes are not directly excited. Therefore, the modal equations of motion form an autoparametric system. Van der Pol's method is employed to determine the frequency response curves (FRCs) for harmonic vibrations in modal coordinates. The FRCs and time histories in modal coordinates are calculated when two or three TMDs are installed on the structure; subsequently, those in physical coordinates are determined via coordinate transformation. Numerical results indicate that localization may occur when more than two modes appear simultaneously. Furthermore, the excitation frequency range where localization occurs is theoretically clarified based on backbone curves.
Development of Local Ductile Failure Assessment Method and Its Application to Four Alloys—Part I: Stress–Strain Relation and Analysis Without the Effect of Lode Angle
Authors: Takahashi Yukio , Shigeyama Haruhisa 
Published: January 2025

Abstract
In evaluating the margin against fracture under various loadings, resistance against initiation and propagation of fracture needs to be evaluated. Elastic-plastic finite element (FE) analysis serves as a powerful tool for such assessment but prediction of plastic deformation and stress state in structures needs stress–strain relations to be implemented in the analysis. For avoiding the necessity of testing and processing the data each time, true stress–strain relations whose constants can be determined from fundamental properties such as yield or proof stress, tensile strength, rupture elongation, and reduction of area were developed based on the results of uniaxial tensile tests on many kinds of alloys used in nuclear power plants. Tensile tests were also conducted on notched round bar and grooved plate specimens made from four representative materials at various temperatures below the creep regime. Conventional large strain elastic-plastic analyses were performed on these specimens to elucidate the necessity of incorporation of the effect of damage on deformation in addition to a failure criterion. Then the calculation of damage based on equivalent plastic strain rate and stress triaxiality factor was introduced with an aim of predicting failure and the gradual decrease in deformation resistance. It was found that, although the predictions became more realistic, the behavior of some of the specimens could not be predicted with a sufficient accuracy when the effects of the stress triaxiality factor were calibrated based on the analyses of other types of specimens, suggesting the necessity of introducing another parameter which will be addressed in a subsequent paper.
In-Cylinder Imaging and Emissions Measurements of Cold-Start Split Injection Strategies
Authors: Gutierrez Luis G. , Wooldridge Margaret S. , Petersen Benjamin R. , Wooldridge Steven T. 
Published: January 2025

Abstract
Strategies to mitigate cold-start emissions are critical to meet stringent standards for particulate and regulated gaseous emissions from direct injection spark ignition (DISI) engines. The objective of the current work was to establish an experimental protocol for cold-start studies and to identify the in-cylinder phenomena important during engine warming in terms of engine power and stability and engine-out particulates, NOx, and unburned hydrocarbon emissions. Metal-engine experiments were conducted with ambient intake air temperature and coolant air temperature of 20 °C to quantify the sensitivity of the performance of a single-cylinder engine to timing of a strategy using two injection events per power cycle and late spark ignition. The results showed strong sensitivity to the timing of the second injection event and weak sensitivity to the timing of the first injection. Complementary high-speed imaging experiments were conducted with the same engine where the fuel spray and combustion characteristics were visualized during cold-start split-injection operation. The imaging data showed the sources of particulates were due to fuel impingement on combustion chamber surfaces and due to fuel rich regions, in particular regions where the fuel recondensed due to the conditions associated with late ignition timing. The combination of engine-out particulate and imaging measurements indicated smaller particles (10–20 nm) were associated with fuel impingement on surfaces, and larger particles (20–200 nm) were associated with fuel rich “pockets”.
Improved Engine Data Acquisition System and Interface to Enable Experimentation With Emerging Alternative Fuels in a Spark-Ignited Cooperative Fuel Research Engine
Authors: Loprete Jason , Dimosthenous Christos , Assanis Dimitris 
Published: January 2025

Abstract
In the face of new engine research challenges, legacy hardware and once state-of-the-art assumptions may become less relevant, especially those made due to the computational limitations of the hardware at the time of initial development. Such legacy elements can potentially limit the effectiveness of accurately describing key parameters or metrics during experimentation or postprocessing. As the behavior of novel fuels is also not always fully understood, this highlights the need for tools to guide the experimental design to avoid unexpected and potentially dangerous outcomes. This paper details the conversion of an existing data acquisition system for a spark-ignited single-cylinder cooperative fuel research (CFR) engine to handle a variety of different emerging alternative fuels. Modifications to the in-house legacy LabVIEW program and data acquisition system are detailed, with emphasis on providing additional tools to aid in the experimentation expediency and safety. The existing CFR testing facility is converted from a single liquid or single gaseous fuel capable system to a multifuel compatible system, complete with on-the-fly calculations of mass, energy, and volume fractions of existing fuel blends, increased low-speed sampling rates, and a calculating tool to command fuel flow set-points for a given blend fraction, equivalence ratio and airflow set-point. Additional factors, such as sensor selection and communication, are discussed with an emphasis on reducing experimental uncertainty. Overall, this work provides insights into possible adjustments and considerations when upgrading existing experimental setups to accommodate emerging alternative fuel use.
Power Corrections in the Transient Plane Source Method
Authors: Landry David , Flores Renzo 
Published: January 2025

Abstract
The transient plane source (TPS) is a well-known method for measuring the thermal conductivity, thermal diffusivity, and specific heat capacity of solids, liquids, pastes, and powders. The method assumes that the heat source delivers a constant power throughout the measurement. However, in real-world measurements, the effective power is reduced due to the temperature coefficient of resistance (TCR) and the heat capacity of the sensor. In this paper, we present first-order corrections to the average temperature of the sensor, accounting for the power reduction caused by the TCR and the heat capacity of the TPS sensor. To verify the corrections, TPS measurements were performed on Pyroceram 9606 at multiple initial powers. The measured properties without the corrections showed a significant trend with the power used. The first-order corrections significantly decreased the trend of the measured thermal conductivity with power, validating the improvements the corrections make to the TPS method.
NoodlePrint: Cooperative Multi-Robot Additive Manufacturing With Helically Interlocked Tiles
Authors: Ebert Matthew , Stone Ronnie F. P. , Koithan John , Zhou Wenchao , Pharr Matt , Estrin Yuri , Akleman Ergun , Sha Zhenghui , Krishnamurthy Vinayak 
Published: January 2025

Abstract
We present NoodlePrint, a generalized computational framework for maximally concurrent layer-wise cooperative 3D printing (C3DP) of arbitrary part geometries with multiple robots. NoodlePrint is inspired by a recently discovered set of helically interlocked space-filling shapes called VoroNoodles. Leveraging this unique geometric relationship, we introduce an algorithmic pipeline for generating helically interlocked cellular segmentation of arbitrary parts followed by layer-wise cell sequencing and path planning for cooperative 3D printing. Furthermore, we introduce a novel concurrence measure that quantifies the amount of printing parallelization across multiple robots. Consequently, we integrate this measure to optimize the location and orientation of a part for maximally parallel printing. We systematically study the relationship between the helix parameters (i.e., cellular interlocking), the cell size, the amount of concurrent printing, and the total printing time. Our study revealed that both concurrence and time to print primarily depend on the cell size, thereby allowing the determination of interlocking independent of time to print. To demonstrate the generality of our approach with respect to part geometry and the number of robots, we implemented two cooperative 3D printing systems with two and three printing robots and printed a variety of part geometries. Through comparative bending and tensile tests, we show that helically interlocked part segmentation is robust to gaps between segments.
Vision-Language Models for Design Concept Generation: An Actor-Critic Framework
Authors: Ghasemi Parisa , Moghaddam Mohsen 
Published: January 2025

Abstract
We introduce a novel actor-critic framework that utilizes vision-language models (VLMs) and large language models (LLMs) for design concept generation, particularly for producing a diverse array of innovative solutions to a given design problem. By leveraging the extensive data repositories and pattern recognition capabilities of these models, our framework achieves this goal through enabling iterative interactions between two VLM agents: an actor (i.e., concept generator) and a critic. The actor, a custom VLM (e.g., GPT-4) created using few-shot learning and fine-tuning techniques, generates initial design concepts that are improved iteratively based on guided feedback from the critic—a prompt-engineered LLM or a set of design-specific quantitative metrics. This process aims to optimize the generated concepts with respect to four metrics: novelty, feasibility, and problem-solution relevancy, and variety. We explored the efficacy of incorporating images alongside text in conveying design ideas within our actor-critic framework by experimenting with two mediums for the agents: vision-language and language-only. We extensively evaluated the framework through a case study using the AskNature dataset, comparing its performance against benchmarks such as GPT-4 and real-world biomimetic designs across various industrial examples. Our findings underscore the framework's capability to iteratively refine and enhance the initial design concepts, achieving significant improvements across all metrics. We conclude by discussing the implications of the proposed framework for various design domains, along with its limitations and several directions for future research in this domain.
Failure Analysis of a Waste Heat Boiler of a Sulfur-Burning Sulfuric Acid Plant
Authors: Wang Yilin , Zhang Ming , Li Mengli , Liu Long , Wang Weiqiang 
Published: January 2025

Abstract
The waste heat boiler in a sulfur-burning sulfuric acid plant experienced failures, specifically furnace tube bursting and tube sheet leakage. Samples were extracted from the front tube sheet and the tubes that had failed, located where the waste heat boiler had developed leaks. The compositions, microstructures, mechanical properties, and crack morphology of the tube sheet and the tubes were analyzed. There were many small cracks in the tube-sheet joints, and Na was detected in the cracks. Na was also found in the expanded connection area between the tubes and the tube sheet. The inner wall of the tubes near the tube burst area was severely corroded. The amount of S on the inner walls of the tubes near the tube burst area was significantly higher than that on the outer walls of the tubes. Through relevant analyses, the following conclusions were obtained: the alkali stress corrosion cracks widely appeared in the tube-sheet joint. The sulfuric acid formed by the mixture of leaked water and high-temperature flue gas flowed into the tubes, and relevant tubes were seriously corroded and eventually burst.
A Proportional Control Strategy for Stiffness Tuning of Parallel Manipulators
Authors: Verotti Matteo , Morandini Marco , Masarati Pierangelo 
Published: January 2025

Abstract
This article presents a control strategy for the stiffness regulation of parallel manipulators based on the implementation of a simple proportional controller. Starting from the assignment of the stiffness or compliance matrix in the task space, defined by the application-specific requirements, a proper control action is calculated by considering the translational and rotational compliances of the end effector. The proposed approach is applied in SE(2) and SE(3), addressing the analysis of the 3RRR planar parallel manipulator and the 6UPS Stewart–Gough platform. The proposed control scheme decouples the effects of the applied force and moment on the end effector displacement and rotation. Numerical examples are presented, with multibody simulations performed to verify the effectiveness of the proposed approach. The effect of friction in the active and passive joints is also investigated.
Solar Collector Featured Dryer Performance Enriched by the Adaptations of Phase Change Material Embedded With Fin Collector Absorber
Authors: Venkatesh R. , Logesh K. , Vinayagam Mohanavel , Kumar Ashok , Chaturvedi Rishabh , Prabagaran S. , M. Soudagar Manzoore Elahi , Salmen Saleh Hussein , Al Obaid Sami 
Published: January 2025

Abstract
The solar dryer was an effective choice for drying agriculture products because it is cost-effective and requires no external energy for process drying. The fluctuation in drying temperature due to irregular radiation availability influences the food product quality and drying time significantly during the drying process using a solar dryer. In this study, the solar dryer integrated with a solar collector is experimentally studied using phase change material (PCM—paraffin wax) embedded with a fin collector absorber. The drying products such as banana (DP1), and potato (DP2) slices are used in the thickness of 2 mm. The absorber with PCM and fins configuration in the solar collector leads to better thermal performance compared to conventional solar collector absorbers and PCM absorbers. The dryer with PCM and fins-integrated solar collector absorber achieved higher outlet air temperatures of 56.5 °C and 58.1 °C for DP1 and DP2 61, respectively. Additionally, the collector efficiency, moisture, and drying rate for dryers with PCM-integrated solar collector absorbers of DP1/DP2 products were improved by 73.4/75.4%, 0.92/0.95, and 0.88/0.9 kg/h, respectively. Therefore, the dryer with PCM and fins-integrated solar collector absorber is the best choice for drying agricultural products using solar technologies.