Computational Finite Element Analysis Research Articles

Abstract 589: A Fluid Structure Interaction Workflow For Studying Aortic Dissections

Introduction: After diagnosis and treatment of aortic dissections, there is the potential for future complications such as the growth or rupture of pre-existing aneurysms or further dissection of the aorta. This susceptibility to future complications is what we refer to as “aortic fragility”. Current computational models of aortic dissection rely upon computational fluid dynamics (CFD) or finite element analysis (FEA); however, there are limitations to using either method alone. Using a healthy patient aorta as our control case, we developed a novel method of coupling CFD with FEA in a fluid surface interaction (FSI) model for studying aortic dissection. Methods: We developed this FSI model by first segmenting aortas from CT scans to generate patient-specific models. With these meshes, we used a cardiac cycle fluid velocity profile to perform CFD and extracted static pressure values on the aortic wall at systole and diastole. We applied these pressures to our FEA model as the mechanical load driving wall deformation. Results: We successfully completed the CFD portion of our FSI simulation with results consistent with our expectations. Velocity data at the ascending and descending aorta, branches and arch correctly reflect our input cardiac cycle velocity profile. Histograms of static pressure values on the aortic wall at systole and diastole show that the mean systolic pressure is greater than the mean diastolic pressure, thus reflecting our expectations. Heat maps of this data reveal the aortic arch and branches to be areas of highest pressure, with pressure gradually decreasing in the distal aorta. Conclusion: With our healthy aorta control, we have successfully validated the CFD component of our FSI model. Our methods improve upon previous models by coupling CFD with FEA, allowing the use of realistic pressure loads derived from fluid analysis. We plan to further improve by validating the FEA component of our model and applying our methodology to dissection geometries. With this FSI workflow, we hope to more accurately model and predict the deformation patterns of aortic dissection in fragile aortas.

Extended law of laplace for measurement of the cloverleaf anatomy of the aortic root

The cross-sectional shape of the aortic root is cloverleaf, not circular, raising controversy regarding how best to measure its radiographic “diameter” for aortic event prediction. We mathematically extended the law of Laplace to estimate aortic wall stress within this cloverleaf region, simultaneously identifying a new metric of aortic root dimension that can be applied to clinical measurement of the aortic root and sinuses of Valsalva on clinical computerized tomographic scans. Enforcing equilibrium between blood pressure and wall stress, finite element computations were performed to evaluate the mathematical derivation. The resulting Laplace diameter was compared with existing methods of aortic root measurement across four patient groups: non-syndromic aneurysm, bicuspid aortic valve, Marfan syndrome, and non-dilated root patients (total 106 patients, 62 M, 44 F). (1) Wall stress: Mean wall stress at the depth of the sinuses followed this equation: Wall stress = BP × Circumscribing circle diameter/(2 × Aortic wall thickness). Therefore, the diameter of the circle enclosing the root cloverleaf, that is, twice the distance between the center, where the sinus-to-commissure lines coincide, and the depth of the sinuses, may replace diameter in the Laplace relation for a cloverleaf cross-section (or any shaped cross-section with two or more planes of symmetry). This mathematically derived result was verified by computational finite element analyses. (2) Diameters: CT scan measurements showed a significant difference between this new metric, the Laplace diameter, and the sinus-to-commissure, mid-sinus-to-mid-sinus, and coronal measurements in all four groups (p-value < 0.05). The average Laplace diameter measurements differed significantly from the other measurements in all patient groups. Among the various possible measurements within the aortic root, the diameter of the circumscribing circle, enclosing the cloverleaf, represents the diameter most closely related to wall stress. This diameter is larger than the other measurements, indicating an underestimation of wall stress by prior measurements, and otherwise provides an unbiased, convenient, consistent, physics-based measurement for clinical use.Graphical abstract“Diameter” applies to circles. Our mathematical derivation of an extension of the law of Laplace, from circular to cloverleaf cross-sectional geometries of the aortic root, has implications for measurement of aortic root “diameter.” The suggested method is as follows: (1) the “center” of the aortic root is identified by drawing three sinus-to-commissure lines. The intersection of these three lines identifies the “center” of the cloverleaf. (2) The largest radius from this center point to any of the sinuses is identified as the “radius” of the aortic root. (3) This radius is doubled to give the “diameter” of the aortic root. We find that this diameter best corresponds to maximal wall stress in the aortic root. Please note that this diameter defines the smallest circle that completely encloses the cloverleaf shape, touching the depths of all three sinuses.

Computational finite element analysis of electromagnetic radiative nanofluid containing motile germs with chemical reactive process

In this paper, to characterize the appearances of bio-convection and influencing microorganisms in movements of influenced Walters-B nanofluid, we built a process in a stretchable sheet utilizing Fourier’s and Fick’s laws. The mass and temperature diffusion hypothesis proposed by Cattaneo and Christov has been considered. Also, the Buongiorno phenomenon for nanofluid wave in the Walters-B fluid is used, according to the Cattaneo–Christov connection. A system of regulating partial differential equations (PDEs) is transformed into ordinary differential equations (ODEs) using similarity transformations. Due to the Galerkin finite element mode, the software COMSOL is utilized to derive mathematical solutions for nonlinear equations (G-FEM). Temperature, velocity, and microorganism analysis are all investigated using logical and pictorial metrics. Nanoparticle concentrations are also calculated by considering various approximations of well-known physical characteristics. The simulations of this model demonstrate a straight association between the heat field and the current Biot number and factor of the Walters-B liquid. The temperature field is improved to increase the thermal Biot amount and factor approximations for the Walters-B fluid.

Open-source simulation of strongly-coupled fluid-structure interaction between non-conformal interfaces

Design code-based “life-safety” requirements for structural earthquake and tsunami design offer reasonable guidelines to construct buildings that will remain standing during a tsunami or seismic event. Much less consideration has been given to assessing structural resilience during sequential earthquake and tsunami multi-hazard events. Such events present a series of extreme loading scenarios, where damage sustained during the earthquake influences structural performance during the subsequent inundation. Similar difficulties exist with respect to damage sustained during tropical events, as wind and fluid loading may vary with structural response or accumulated damage. To help ensure critical structures meet a “life-safety” level of performance during such multi-hazard events, analysis software capable of simulating simultaneous structural and fluid dynamics must be developed. To address this gap in understanding of non-linear fluid-structure-interaction (FSI), an open-source tool (FOAMySees) was developed for simulation of tsunami and wave impact analysis of post-earthquake non-linear structural response of buildings. The tool is comprised of the Open-source Field Operation And Manipulation software package and OpenSeesPy, a Python 3 interpreter of OpenSees. The programs are coupled via preCICE, a coupling library for partitioned multi-physics simulation. FOAMySees has been written to work in a Linux OS environment with HPC clusters in mind. The FOAMySees program offers a partitioned conventional-serial-staggered coupling scheme, with optional implicit iteration techniques to ensure a strongly-coupled two-way FSI solution. While FOAMySees was developed specifically for tsunami-resilience analysis, it may be utilized for other FSI applications with ease. With this coupled Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) program, tsunami and earthquake simulations may be run sequentially or simultaneously, allowing for the evaluation of non-linear structural response to multi-hazard excitation.

Design analysis of a printed circuit heat exchanger for HTGR using a 3D finite elements model

The intermediate heat exchanger (IHX) is a critical component in most of the High Temperature Gas-cooled Reactor plant layouts. The printed circuit heat exchanger (PCHE) has been studied as an advantageous candidate for this application last years. The extreme operating conditions of the IHX and the higher structural integrity of the PCHE over other heat exchanger technologies have motivated these studies. In this work, the structural assessment of a zigzag channel PCHE under IHX conditions was carried out by means of computational fluid dynamics (CFD) and Finite Element Analysis (FEA). The ASME Boiling and Pressure Vessel Code, Sections III and VIII, were applied to evaluate the safety operation of the PCHE. The temperature field in steady state was obtained using a 3D CFD model. Then it was used as thermal load to calculate thermal stress using a FEA model. The influence of the zigzag angle and the bend radius on the thermal and mechanical stresses was analyzed. Thus, the values studied for the zigzag angle were 0° (straight), 15°, 30 and 45°, while for the bend radius were 0.5 mm, 2 mm, 4 mm and 6 mm. The importance of the 3D temperature field to calculate thermal stress in a zigzag channel was evidenced due to the appearance of local temperature differences in the channel cross-sections. The change in flow direction created areas of higher local temperatures where the flow lines change their directions impacting the channel wall. A significant thermal stress concentration was found in these areas, and this effect intensified with increasing zigzag angle. The bend radius was decisive to reduce the thermal stress concentration when the zigzag angle was higher than 15°.

Thermal design and performance of low beta cryomodule for CAFe

China initiative Accelerator Driven System (CiADS) has developed several kinds of cryomodules for superconducting proton linac at IMP. The low beta cryomodules had been designed, fabricated, assembled, and tested for the linac. To meet the requirements of minimizing heat transfer and operational stability, the thermal design and performance of low beta cryomodules have been studied. In this paper, finite element analysis and numerical calculation have been carried out on the design of important components such as thermal insulating support, bellows, thermal shield, power coupler, current leads and so on. Then the heat loads at various temperature levels have been summarized. Besides, the performance of the cryomodules including the cool down, equipment operating data, and heat load measurements are reported. The trial test result of low beta cryomodules shows that the various technical indexes satisfied the technical requirements.

Numerical Simulation of Low-Pressure Carburizing and Gas Quenching for Pyrowear 53 Steel

The hardness and phase composition are, among other things, the critical material properties considered in the quality control of aerospace gears made from Pyrowear 53 steel after high-pressure gas quenching. The low availability of data on and applications of such demanding structures justify investigating the choice of the material and the need to improve its manufacturability. In this study, computational finite-element analyses of low-pressure carburizing followed by oil and gas quenching of Pyrowear 53 steel were undertaken, the objective of which was to examine the influence of the process parameters on the materials’ final phase composition and hardness. The material input was prepared using JMatPro. The properties computed by the CALPHAD method were calibrated by the values obtained from physical experiments. The heat transfer coefficient was regarded as an objective variable to be optimized. A 3D model of the Standard Navy C-ring specimen was utilized to predict the phase composition after the high-pressure gas quenching of the steel and the hardness at the final stage. These two parameters are considered good indicators of the actual process parameters and are used in the industry. The results of the simulation, e.g., optimized heat transfer coefficients, cooling curves, and hardness and phase composition, are presented and compared with experimental values. The accuracy of the simulation was validated, and a good correlation of the data was found, which demonstrates the quality of the input data and setup of the numerical procedure. A computational approach to heat treatment processes’ design could contribute to accelerating new procedures’ implementation and lowering the development costs.

Choosing the optimal mandible position for inferior alveolar nerve block (IANB) using finite element analysis

BackgroundOne of the most popular methods of local anesthesia in dentistry, inferior alveolar nerve block (IANB) involves the blockade of the inferior alveolar nerve (IAN) and lingual nerve (LN) in the pterygomandibular space. Despite the large number of works describing the contents of this space, the spatial displacements of the anatomical structures of this area at different positions of the mandible have not been sufficiently studied. The aim of our study was to study the spatial movements of the IAN and inferior alveolar artery (IAA) at various positions of the mandible using computer simulation and finite element analysis to find the safest way to conduct IANB. Materials and methodsReverse engineering was used to create a model of the cranial base and the mandible based on computed tomography (CT) data obtained from patient N (male, 24 years old), the arteries of the head and neck were designed from the data of multiphase angiography of patient M (female, 61 years old). Masticatory muscles, sphenomandibular ligament, temporomandibular joint and mandibular nerve were modeled in the SolidWorks software package based on an open database of anatomical structures. The finite element grid was generated in the Solidworks software.In the first series of experiments, the displacement of the mandible was modeled along the vertical axis down by 48 mm (maximum opening of the mouth), in the second series, the jaw was displaced vertically by 48 mm with a simultaneous transversal movement of 10 mm, in the third series, the jaw was displaced along the vertical axis down by 34 mm and transversally by 22 mm. ResultsThe largest distance between IAN and IAA was noted in the third series of experiments. The distance between the nerve and the vessel was minimal in the first series, with an open mouth without lateral displacements. ConclusionThe generated computer model opens new possibilities for studying the dynamic anatomy of the pterygomandibular space. The results of this study can be used for further experimental and clinical trials to find the safest approach to the implementation of IANB, as well as applied in the practice of the educational process.

A novel approach to reduce fan rotor blades stress in case of resonance due to inlet flow distortion by means of piezoelectric actuators

Resonant vibration condition involves a drop in the life-cycle of the components and is one of the main causes of high cycle fatigue failure (HCF) in turbomachinery blades. As a consequence vibration damping techniques play a key role for turbomachinery designers. Even though resonant vibration conditions can be identified by means of the Singh’s Advanced Frequency Evaluation (SAFE) diagram at the design level, not all resonant conditions can be avoided. Among these methods, systems of piezoelectric (PZT) actuators can be tuned to actively damp the vibrations caused by resonant excitations. In this work, an analytical model was developed to identify the optimal voltage distribution that maximises the reduction in blade stress. The model considers the flexural–torsional–extensional deformations coupling due to the pre-twisting, non-constant cross-section and inertial loads of the rotating blades. A typical case was examined to demonstrate the effectiveness of the proposed method, which involved vibration induced by inlet flow distortion in an axial fan stage coupled with a three-strut front frame. A decoupled approach based on Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) simulations was used to evaluate the aerodynamic loads and to numerically validate the optimal voltage distribution on the PZT actuator pairs. The results show that the proposed method alleviates the effects of the resonant response to an inlet flow distortion on a fan integrally bladed disc (blisk) and the optimal voltage distribution predicted by the model is the one that achieves the highest blade stress mitigation.

Study on optimization of pouring time for late poured band

The setting of the late poured band is an effective measure to control the differential settlement and the stress concentration of the foundation. However, the lag of the pouring time of the late poured band will also bring adverse effects to the construction process. Taking a large commercial complex as an example, Midas GTS NX finite element software is used for the overall foundation modeling, and the collaborative calculation of settlement is carried out by adjusting the composite foundation scheme. The calculation results of conventional codes are compared and analyzed, and the scheme is verified and optimized. Then, the variation value of differential settlement on both sides of the late poured band with loading is studied by simulating the graded loading of each area in the whole process of construction. By comparing the variation value of differential settlement and the calculation value of differential deformation that the stiffness of the late poured band can resist and the limit value of codes, the time node of late poured band pouring in advance can be obtained, and finally the influence of early pouring of the late poured band on the collaborative settlement of the foundation is verified and calculated. The results show that: the settlement calculation of finite element analysis is generally smaller than that of standard calculation; The settlement at the edge of the raft is small, and the settlement at the center of the raft and the places with large load is large; Considering the interaction of the whole raft and subgrade under the raft, this method can verify and optimize the design scheme of composite foundation and save the pouring time of the late poured band. The experience and achievements so made can be used as a reference for similar projects.

Long-term monitoring of earth dam of the Charvak hydroelectric power plant (HPP) considering the water level of the reservoir

A numerical method for determining the settlement and stress-strain state (SSS) of high earth dam of the Charvak hydroelectric power plant is developed based on the finite element method (FEM). The results were compared with the available data from long-term field observations and with records of continuous geodetic monitoring of the dam behavior based on processed space radar images obtained from the Sentinel-1 satellite. To conduct calculations, OJSC Gidroproekt of the Republic of Uzbekistan provided the structural and piecewise non-homogeneous physical and mechanical characteristics of soil of the structure body. The results of calculations of vertical displacements, normal stresses, and pore pressure were compared with field observation data for the section in which the corresponding control and measuring equipment was installed. A cause-and-effect relationship was identified between the water level in the reservoir and the deformation of the dam. The difference between the theoretical results obtained and field observations was up to 10%. A comparison of the results obtained using the finite element analysis calculations (taking into account the level of water filling in the reservoir) with the actually measured deformations of the dam during the filling of the reservoir, and with processed space monitoring data depending on the time of year, showed a good agreement between the measured and calculated displacements.

Sequential parameter optimization for algorithm-based design generation using data from multiphysics simulations

The implementation of algorithmic modelling in CAD technologies is an opportunity to reduce manual design work in repetitive design tasks. This increases the importance of design automation and digital workflows. This technology can process the results from computational fluid dynamics (CFD) and finite element analysis (FEA) automatically and can optimize designed geometries sequentially. Nevertheless, this design process often sets high computational requirements. The aim of this paper is to present a design automation workflow that reduces the computational time of a design process. The computational resource requirements of the system are reduced by using knowledge-based engineering techniques to obtain information from previous successful designs, decomposing the design into sub-parts according to their functions and optimizing each sub-part individually. Furthermore, through algorithmic modelling, the different input geometries required for the physical description of each simulation are made separately. This allows different design simplifications to be made for each simulation domain. Once the output of the simulations is obtained, the design is evaluated in CAD to optimize the geometry. After each sub-part has been optimized, the sub-parts are composed to obtain the final design. The case study of a reactor for methanol synthesis supports the results of this paper.

Advanced Casting Techniques for Complex-Shaped Components: Design, Simulation and Process Control

The advancement of manufacturing technology has resulted in an increasing need for detailed, lightweight, and high-performance components with complicated geometries across many sectors. The emergence of advanced casting processes has been crucial in addressing these needs, as they provide the potential to manufacture components with complex geometries, enhanced mechanical characteristics, and minimised material wastage. The present study delves into the intricate domain of advanced casting processes, with a specific emphasis on the areas of design, simulation, and process control. The design of components with intricate shapes poses difficulties that conventional casting techniques encounter difficulties in surmounting. Simulation methods are crucial for accurately predicting the solidification and flow characteristics in casting processes, as this is essential for the production of components without any defects. Sophisticated simulation technologies, like as computational fluid dynamics (CFD) and finite element analysis (FEA), are utilised in advanced casting processes to model and analyse the intricate thermal and fluid dynamics phenomena that transpire during the casting process. This research provides an in-depth analysis of the role of simulations in enhancing the comprehension of solidification patterns, the identification of probable faults, and the optimisation of gating and riser designs to improve the overall quality of castings.

IMPLEMENTATION OF A DIGITAL TWINNING APPROACH TO IMPROVE DESIGNS OF POLYURETHANE HEART VALVES

Young sub-Saharan African and developing-world patients with rheumatic heart valve diseases urgently require cost-effective prosthetic valves. To design cost-effective polyurethane heart valves, comprehend haemodynamic behaviour, expedite prototype development, and reduce the need for clinical testing for functional evaluation, the implementation of an experimental test digital twinning is essential. The use of computational fluid dynamics (CFD) and finite element analysis (FEA) to improve heart valve replacement designs rapidly, in order to comply with the minimum requirements of Food and Drug Administration (FDA) and International Organization for Standardization (ISO) regulations and specifications, forms the core of this study. This approach is presented, and the results are discussed. A conclusion is drawn about the valve geometric orifice area (GOA) compared with experimental tests. When the valve was fully opened, there was only an 11% difference between the computed experimental and the finite element GOA. Digital simulation revealed additional information such as the locations of stress concentrations. The FE results showed reasonable similarity with in vitro results.

Failure Analysis of Tubing Collapse in a Gas Well

The tubing used in a gas well rarely collapses and fails during applying annulus pressure. In this study, the failure causes of tubing collapse were analyzed by means of data verification, macroscopic observation, magnetic particle inspection, physical and chemical inspection, optical microscopy, and tubing collapse test. Mechanical analysis of the string and full‐scale physical simulation test simulating downhole working conditions. Finally, the verification analysis of the collapse test is carried out by the finite element analysis (FEA). The results showed that (1) the physical dimension, physical and chemical properties, and collapse resistance of this batch of tubing met the requirements of the tubing ordering technical standard. (2) Assuming that the well packer slip was unsealed and could slide freely, the mechanical theoretical analysis of collapsed tubing string and collapse test under simulated working condition load was carried out, which reproduced the load when the tubing collapsed. It can be seen from this that the packer did fail. (3) The FEA calculation results showed that when the external pressure was greater than 30.75 MPa, it would inevitably lead to collapse failure in case of packer unsealed. In conclusion, the root cause for the collapse failure of the 105th underground tubing string was that the packer lost its sealing function, resulting in an abnormal axial load. While under the action of external pressure, the tubing was overloaded and collapsed. It is recommended to carry out verification tests on the material performance of packer slip, the dimensional changes of packer tool outer diameter and inner diameter under actual well conditions, the creep behavior of packer seal, and the performance of shear pin under actual working conditions, especially in the well containing H2S, so as to prevent the pressure leakage of gas well annulus caused by packer unsealing and the reoccurrence of such downhole string collapse accidents. The first collapse test under simulated working condition load is conducted in this paper. Analyzing the collapse failure work and putting forward suggestions to effectively prevent similar failures from happening again are of great significance to the oilfield.

Design, Development and Computational Finite Element Analysis (FEA) of an Electric Two-Wheeler Frame

Abstract: The primary objective of this paper is to describe the complete design procedure for developing a frame of an electric two-wheeler. This chassis work concentrates more on the frame component and its functionalities. A complete and step-by-step approach is facilitated in the design. The process involves identification of the master layout of the vehicle with the determination of centre of gravity and dimensional constraints. Material selection for the frame is done by adopting Ashby’s approach and principles of mechanics of solids are utilized in tube dimension calculations. The paper centralizes effectively on the Computer Aided Engineering (CAE) by adopting computational Finite Element Analysis (FEA). The FEA includes static structural analysis of the frame under various loading conditions, modal analysis, harmonic analysis and impact analysis. The computational aid combined with the analytical methods help the efficient and effective design, development and optimization of the frame structure.

Earthing Resistance and Poldzolic Soil Resistivity at PT. Perta Samtan Gas Field Extraction Plant Prabumulih

It is important to undertake research at the location of PT. Perta Samtan Gas Field Extraction Plant Prabumulih with Podzolik soil type (yellow gravel clay) and analysis in order to prevent work accidents and the risk of fire caused by leakage current at the gas processing extraction installation. Direct measurement of soil resistance value is used as the basis for the methodology, which is followed by literature study as background information and technical comprehension of experimental research. The outcomes of the research study are then compared using Comsol simulation with the computational method of computational finite element analysis of the resulting resistance. According to the data, the resistivity of the podzolic soil was 214.4 Ωm, while the Comsol simulation yielded a resistance value per meter of 209.1 Ω and 196.7Ω, respectively. The Comsol simulation demonstrates that, in order to obtain a ground resistance value of 1 ohm on a Single rod system with Fe material, it is necessary to optimize the depth of the grounding electrode, which can range from 3 meters to 1053 meters d. In the simulation, the results of soil resistance measurements and the Comsol Multiphysics application are obtained, and the difference is calculated with a percentage error of 1.62%.

Вплив включення із функціонально-градієнтного матеріалу на концентра-цію напружень в тонких пластинах та циліндричних оболонках з круговим отвором

ology, in particular, space-rocket engineering, oil-and-gas engineering, power engineering, construction, etc. The presence of openings in their plate and shell components leads to a sharp increase in local stresses, which, under certain conditions, may trigger destructive processes. The use of functionally graded materials (FGMs) with certain mechanical properties can significantly reduce the stress concentration in the vicinity of local concentrators in the form of openings, cutouts, fillets, grooves, etc. This paper presents the results of computer simulation and finite element analysis of the stress and strain fields of thin plates and thin-walled cylindrical shells with a circular opening and an annular FGM inclusion surrounding it. The effect of the dimensions of the FGM inclusion and the law of variation of its elastic modulus on the stress and strain concentration in the vicinity of the opening was studied. The stress and strain intensity distribution in local stress concentration zones was obtained. It was found that an annular FGM inclusion with certain mechanical properties can reduce the stress concentration factor by more than 30%. In this case, a proportional decrease in strain intensity in the vicinity of the opening is also observed. The law of variation of the elastic modulus of the FGM inclusion and the inclusion width have a significant effect not only on the level of stress and strain concentration, but also on the stress and strain pattern. The results of the large-scale computational experiments show that an FGM annular inclusion reduces both the stress and the strain intensity around the opening. Therefore, the use of annular FGM reinforcements in plates and cylindrical shells with openings makes it possible to control the distribution and magnitude of the stress and strain intensities in local stress and strain concentration zones.

Fatigue Life Analysis of Wind Turbine Tower Based on Finite Element Analysis

According to the IEC64100-1 standard, the design life of wind turbines is usually 20 years, and when the operating life reaches the design life should be decommissioned. However, since the operating conditions of the site are usually better than the design conditions, and the cumulative fatigue damage during the design life is less than the design conditions, the actual life of the turbine components is usually greater than 20 years. The tower is an important supporting mechanism component of a wind turbine, and its safe operation has a significant impact on the life of the unit. In order to evaluate the continuous safe operation period after the unit reaches the design life and improve the economic benefits of the project, this paper selects 66 turbines in a wind farm, and the wind turbine tower is selected as the analysis component. Based on the fatigue life calculation of finite element analysis, it is found through a detailed calculation that under the risk probability of 97.7%, the average remaining life of the tower is 5.6 years, which can continue to operate safely.

A novel technique to simulate and characterize yarn mechanical behavior based on a geometrical fiber model extracted from microcomputed tomography imaging

Textiles and their production machines are increasingly designed using simulations of the textile production process. These simulations require reliable structural yarn models. In practice, these models are often based on simplifying assumptions concerning the underlying geometry. However, in recent years more realistic geometrical fiber models have been developed, but have not been used to estimate the structural properties of yarns. The current contribution presents a new methodology to obtain a structural yarn model through numerical simulations based on a high-fidelity geometrical yarn model. Starting from microcomputed tomography data of a real-life natural fiber yarn used in air-jet weaving, a geometrical yarn model is constructed by tracing the individual fibers. This geometry is then incorporated in a computational finite-element analysis framework to obtain the yarn tensile and bending behavior through a simulated tensile test and Peirce cantilever test. Finally, the results are validated by comparison with experimental data. It is shown that this new technique succeeds to estimate the tensile and bending behavior. The presented methodology allows one to gain fundamental insight into the internal deformations and stresses in the yarn. Moreover, it is an important first step toward statistical studies on the structural yarn behavior on the microscale level and toward homogenized macro-models originating from a fully digital workflow.