Transient thermal finite-element analysis of fused filament fabrication process

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chitralekha Nahar ◽  
Pavan Kumar Gurrala
Keyword(s):  
Finite Element ◽  
Thermal Properties ◽  
Thermal Behavior ◽  
Sintering Temperature ◽  
Bond Formation ◽  
Processing Parameters ◽  
Temperature Dependent ◽  
Fused Filament Fabrication ◽  
Time Duration ◽  
Content Type

Purpose The thermal behavior at the interfaces (of the deposited strands) during fused filament fabrication (FFF) technique strongly influences bond formation and it is a time- and temperature-dependent process. The processing parameters affect the thermal behavior at the interfaces and the purpose of the paper is to simulate using temperature-dependent (nonlinear) thermal properties rather than constant properties. Design/methodology/approach Nonlinear temperature-dependent thermal properties are used to simulate the FFF process in a simulation software. The finite-element model is first established by comparing the simulation results with that of analytical and experimental results of acrylonitrile butadiene styrene and polylactic acid. Strand temperature and time duration to reach critical sintering temperature for the bond formation are estimated for one of the deposition sequences. Findings Temperatures are estimated at an interface and are then compared with the experimental results, which shows a close match. The results of the average time duration (time to reach the critical sintering temperature) of strands with the defined deposition sequences show that the first interface has the highest average time duration. Varying processing parameters show that higher temperatures of the extruder and envelope along with higher extruder diameter and lower convective heat transfer coefficient will have more time available for bonding between the strands. Originality/value A novel numerical model is developed using temperature-dependent (nonlinear) thermal properties to simulate FFF processes. The model estimates the temperature evolution at the strand interfaces. It helps to evaluate the time duration to reach critical sintering temperature (temperature above which the bond formation occurs) as it cools from extrusion temperature.

Using scaled FE solutions for an efficient coupled electromagnetic–thermal induction machine model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Martin Marco Nell ◽  
Benedikt Groschup ◽  
Kay Hameyer
Keyword(s):  
Finite Element ◽  
Thermal Behavior ◽  
Fe Simulation ◽  
Operation Mode ◽  
Induction Machine ◽  
Optimization Procedure ◽  
Machine Model ◽  
Content Type ◽  
Thermal Network ◽  
Scaling Procedure

Purpose This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure is coupled to an analytic three-node-lumped parameter thermal network (LPTN) model enabling the possibility to adjust the machine losses in the simulation to the actual calculated temperature. Design/methodology/approach The proposed scaling procedure of IMs allows the possibility to scale the solutions, particularly the losses, of a beforehand-performed FE simulation owing to temperature changes and therefore enables the possibility of a very general multiphysics approach by coupling the FE simulation results of the IM to a thermal model in a very fast and efficient way. The thermal capacities and resistances of the three-node thermal network model are parameterized by analytical formulations and an optimization procedure. For the parameterization of the model, temperature measurements of the IM operated in the 30-min short-time mode are used. Findings This approach allows an efficient calculation of the machine temperature under consideration of temperature-dependent losses. Using the proposed scaling procedure, the time to simulate the thermal behavior of an IM in a continuous operation mode is less than 5 s. The scaling procedure of IMs enables a rapid calculation of the thermal behavior using FE simulation data. Originality/value The approach uses a scaling procedure for the FE solutions of IMs, which results in the possibility to weakly couple a finite element method model and a LPTN model in a very efficient way.

Influence of various sintering parameters and the temperature dependent scaling on the dynamic hysteresis behavior of Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 ceramics

2020 ◽  
Vol 17 (1) ◽  
pp. 273-290
Author(s):  
P. Suresh ◽  
P. Mathiyalagan ◽  
K.S. Srikanth
Keyword(s):  
Electric Field ◽  
Coercive Field ◽  
Remnant Polarization ◽  
Sintering Temperature ◽  
Scaling Relations ◽  
Temperature Dependent ◽  
Content Type ◽  
Hysteresis Behavior ◽  
Dynamic Hysteresis ◽  
Ferroelectric Hysteresis

PurposeThe article explores the effect of sintering temperature on the ferroelectric hysteresis behavior of the synthesized ceramic material Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 (BCSTZO). It describes how the sintering temperature and its holding time have effect on the polarization-electric field (P-E) loops which is an important characteristic of a ferroelectric material. From the P-E loops obtained, various representative parameters like remnant polarization and coercive field values were extracted and scaling results were systematically established using them.Design/methodology/approachThe present article describes the establishment of scaling relations for coercive field (Ec), remnant polarization (Pr) and back switching polarization (Pbc) as a function of temperature which have been obtained from P-E loops sintered at various temperature and time. This is because sintering temperature plays a pivotal role in determining the hysteresis parameters.FindingsThe temperature dependent scaling of Ec and Pr at sintering temperature of 1400, 1425, 1450 and 1475 °C yields EcαT0.40, EcαT0.80, EcαT0.47, EcαT0.29 and PrαT−1.72, PrαT−1.55, PrαT−1.72, PrαT−1.69 respectively. Further the scaling relations for the samples sintered at 1450 °C at different time interval of 3, 4, 5 and 6 h was also established to bring the effect of sintering in switching the ferroelectric hysteresis parameters.Originality/valueThe findings of this work will prove beneficial for the researchers working in optimization of sintering parameters and will benefit researchers selecting best material among the fabricated samples for further property enhancement. The optimized sample could be explored for multifunctional applications ranging from pyroelectric voltage to piezoelectric energy harvesting. In addition to this, the scaling results help to understand the nature of ferroelectric parameters with sintering. This may open up new avenues for studying the scaling behavior of dynamic hysteresis in synthesized material by focusing on hysteresis area as a function of applied electric fields, frequency and temperature. This reason owes to the fact that electric field and frequency are important parameters for a number of applications like sensor, transducers and medical applications.

Immersed volume method for solving natural convection, conduction and radiation of a hat‐shaped disk inside a 3D enclosure

2012 ◽  
Vol 22 (6) ◽  
pp. 718-741 ◽  
Author(s):  
E. Hachem ◽  
H. Digonnet ◽  
E. Massoni ◽  
T. Coupez
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Thermal Properties ◽  
Natural Convection ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Content Type ◽  
Stabilized Finite Element ◽  
Level Set Function ◽  
Volume Method

PurposeThe purpose of this paper is to present an immersed volume method that accounts for solid conductive bodies (hat‐shaped disk) in calculation of time‐dependent, three‐dimensional, conjugate heat transfer and fluid flow.Design/methodology/approachThe incompressible Navier‐Stokes equations and the heat transfer equations are discretized using a stabilized finite element method. The interface of the immersed disk is defined and rendered by the zero isovalues of a level set function. This signed distance function allows turning different thermal properties of each component into homogeneous parameters and it is coupled to a direct anisotropic mesh adaptation process enhancing the interface representation. A monolithic approach is used to solve a single set of equations for both fluid and solid with different thermal properties.FindingsIn the proposed immersion technique, only a single grid for both air and solid is considered, thus, only one equation with different thermal properties is solved. The sharp discontinuity of the material properties was captured by an anisotropic refined solid‐fluid interface. The robustness of the method to compute the flow and heat transfer with large materials properties differences is demonstrated using stabilized finite element formulations. Results are assessed by comparing the predictions with the experimental data.Originality/valueThe proposed method demonstrates the capability of the model to simulate an unsteady three‐dimensional heat transfer flow of natural convection, conduction and radiation in a cubic enclosure with the presence of a conduction body. A previous knowledge of the heat transfer coefficients between the disk and the fluid is no longer required. The heat exchange at the interface is solved and dealt with naturally.

Secondary use of ABS co-polymer recyclates for the manufacture of structural elements using the FFF technology

2018 ◽  
Vol 24 (9) ◽  
pp. 1447-1454 ◽  
Author(s):  
Piotr Czyżewski ◽  
Marek Bieliński ◽  
Dariusz Sykutera ◽  
Marcin Jurek ◽  
Marcin Gronowski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Injection Moulding ◽  
Testing Machine ◽  
Acrylonitrile Butadiene Styrene ◽  
Processing Parameters ◽  
Strength Properties ◽  
Electronic Equipment ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Hardness Tester

Purpose The aim of this paper is presenting a new application of material obtained from the acrylonitrile butadiene styrene (ABS) recycling process from electronic equipment housings. Elements of computer monitors were used to prepare re-granulate, which in turn was used to manufacture a filament for fused filament fabrication (FFF) additive manufacturing technology. Design/methodology/approach The geometry of test samples (i.e. dumbbell and bar) was obtained in accordance with the PN-EN standards. Samples made with the FFF technology were used to determine selected mechanical properties and to compare the results obtained with the properties of ABS re-granulate mould pieces made with the injection moulding technology. The GATE device manufactured by 3Novatica was used to make the prototypes with the FFF technology. Processing parameters were tested with the use of an Aflow extrusion plastometer manufactured by Zwick/Roell and other original testing facilities. Tests of mechanical properties were performed with a Z030 universal testing machine, a HIT 50P pendulum impact tester and a Z3106 hardness tester manufactured by Zwick/Roell. Findings The paper presents results of tests performed on a filament obtained from the ABS re-granulate and indicates characteristic processing properties of that material. The properties of the new secondary material were compared with the available original ABS materials that are commonly used in the additive technology of manufacturing geometrical objects. The study also presents selected results of tests of functional properties of ABS products made in the FFF technology. Originality/value The test results allowed authors to assess the possibility of a secondary application of used elements of electronic equipment housings in the FFF technology and to compare the strength properties of products obtained with similar products made with the standard injection moulding technology.

Investigation of the effect of B4C amount and sintering temperature on the thermal properties of the material in Al 1070–B4C composites

2021 ◽  
pp. 146442072110355
Author(s):  
Zühtü Onur Pehlivanlı ◽  
Muharrem Pul
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Properties ◽  
Heat Conduction ◽  
Composite Materials ◽  
Composite Structure ◽  
Sintering Temperature ◽  
Reinforcement Ratio ◽  
Heat Conduction Coefficient ◽  
Ambient Temperatures

Today, the usage area of metal matrix and ceramic reinforced composites is increasing and researches in this field are increasing. However, majority of the studies conducted are constituted of studies on investigation of mechanical features of composites. One of the reasons why composite materials are preferred is because these materials have improved thermal property. With this experimental study, it is aimed to contribute to the literature in the area of investigating features of thermal properties. In this study, composite materials were produced at 500 °C, 550 °C and 600 °C sintering temperatures by adding 4%, 8% and 16% B4C to Al 1070 quality aluminium by powder metallurgy technique. Firstly, the microstructures of the composites were investigated. Then, experiments were conducted to determine the specific heat of composite materials at different ambient temperatures together with thermal conductivity measurements. With the data obtained from the experiments, finite-element modelling was done and the thermal properties of the composite structure were optimised. In the microstructure studies, it was determined that with the increase in the B4C reinforcement ratio, the reinforcement agglomeration and porosity in the composite structure were found. As a result of the thermal experiments, it was observed that the thermal conductivity values of the composites were inversely proportional to the amount of B4C reinforcement and as the reinforcement ratio increased, the thermal conductivity values decreased. Besides, it was determined that the sintering temperature has an effect on the thermal conductivity value and that it increases the thermal conductivity of the composites with increasing sintering temperature. The highest heat conduction coefficient was obtained at 4% B4C reinforcement ratio and 600 °C sintering temperature. It was observed that the finite-element models prepared to determine the heat conduction coefficient effectively were consistent with the experimental results.

Finite Element Analysis on Temperature Field of Laser Brazing

2011 ◽  
Vol 295-297 ◽  
pp. 1428-1432
Author(s):  
Zhi Bo Yang ◽  
Li Mei Zhang ◽  
Peng Fei Luo ◽  
Jiu Hua Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Field ◽  
Surface Temperature ◽  
Material Properties ◽  
Processing Parameters ◽  
Temperature Dependent ◽  
Laser Brazing ◽  
Element Analysis ◽  
Fem Model

The purpose of this paper is used Ansys to simulate the temperature field of laser brazing by FEM. The 3-D solid elements are used in FEM model, and nonlinear factors of temperature-dependent material properties are considered. The surface temperature grades have been attained, and the brazing experiment have been conducted, the results show that the wetting of Ni-Cr alloy to diamond is good. This study is useful for selecting reasonable processing parameters on laser brazing.

The influence of infill density gradient on the mechanical properties of PLA optimized structures by additive manufacturing

2021 ◽  
pp. 146442072110071
Author(s):  
AIL Pais ◽  
C Silva ◽  
MC Marques ◽  
JL Alves ◽  
J Belinha
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Additive Manufacturing ◽  
Structural Optimization ◽  
Meshless Method ◽  
Load Case ◽  
Fused Filament Fabrication ◽  
Ductile Metals ◽  
Four Point Bending ◽  
Bending Load

The aim of this work is the development of a novel framework for structural optimization using bio-inspired remodelling algorithm adapted to additive manufacturing. The fact that polylactic acid (PLA, E = 3145 MPa (Young’s modulus) according to the supplier for parts obtained by injection) shows a similar parameterized behavior with ductile metals, in the sense that both materials are characterized by a bi-linear elastic-plastic law, allows to simulate and prototype parts to be further constructed in ductile metals at a lower cost and then be produced with more expensive fabrication processes. Moreover, cellular materials allow for a significant weight reduction and therefore reduction of production costs. Structural optimization algorithms based on biological phenomena were used to determine the density distribution of the infill density of the specimens. Several simple structures were submitted to distinct complex load cases and analyzed using the mentioned optimization algorithms combined with the finite element method and a meshless method. The surface was divided according to similar density and then converted to stereolitography files and infilled with the gyroid structure at the desired density determined before, using open-source slicing software. Smoothing functions were used to smooth the density field obtained with the remodeling algorithms. The samples were printed with fused filament fabrication technology and submitted to mechanical flexural tests similar to the ones analyzed analytically, namely three- and four-point bending tests. Thus, the factors of analysis were the smoothing parameter and the remodeling method, and the responses evaluated were stiffness, specific stiffness, maximum force, and mass. The experimental results correlated (obtaining accuracy of 35% for the three-point bending load case and 5% for the four-point bending load case) to the numerical results in terms of flexural stiffness and it was found that the complexity of the load case is relevant for the efficiency of the functional gradient. The fused filament fabrication process is still not accurate enough to be able to experimentally compare the results based of finite element method and meshless method analyses.

Parallel finite-element method using domain decomposition and Parareal for transient motor starting analysis

2019 ◽  
Vol 38 (5) ◽  
pp. 1507-1520 ◽  
Author(s):  
Yasuhito Takahashi ◽  
Koji Fujiwara ◽  
Takeshi Iwashita ◽  
Hiroshi Nakashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parallel Computing ◽  
Domain Decomposition ◽  
Parallel Computation ◽  
Domain Decomposition Method ◽  
Space Time ◽  
Content Type ◽  
Parallel Performance ◽  
Element Method

Purpose This paper aims to propose a parallel-in-space-time finite-element method (FEM) for transient motor starting analyses. Although the domain decomposition method (DDM) is suitable for solving large-scale problems and the parallel-in-time (PinT) integration method such as Parareal and time domain parallel FEM (TDPFEM) is effective for problems with a large number of time steps, their parallel performances get saturated as the number of processes increases. To overcome the difficulty, the hybrid approach in which both the DDM and PinT integration methods are used is investigated in a highly parallel computing environment. Design/methodology/approach First, the parallel performances of the DDM, Parareal and TDPFEM were compared because the scalability of these methods in highly parallel computation has not been deeply discussed. Then, the combination of the DDM and Parareal was investigated as a parallel-in-space-time FEM. The effectiveness of the developed method was demonstrated in transient starting analyses of induction motors. Findings The combination of Parareal with the DDM can improve the parallel performance in the case where the parallel performance of the DDM, TDPFEM or Parareal is saturated in highly parallel computation. In the case where the number of unknowns is large and the number of available processes is limited, the use of DDM is the most effective from the standpoint of computational cost. Originality/value This paper newly develops the parallel-in-space-time FEM and demonstrates its effectiveness in nonlinear magnetoquasistatic field analyses of electric machines. This finding is significantly important because a new direction of parallel computing techniques and great potential for its further development are clarified.

Investigation on the shaft voltage generation of large synchronous turboalternators

2020 ◽  
Vol 39 (5) ◽  
pp. 1145-1156
Author(s):  
Kevin Darques ◽  
Abdelmounaïm Tounzi ◽  
Yvonnick Le-menach ◽  
Karim Beddek
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Short Circuit ◽  
Element Model ◽  
Stator Winding ◽  
Content Type ◽  
Voltage Generation ◽  
The Impact ◽  
Investigation Process ◽  
Circulating Currents

Purpose This paper aims to go deeper on the analysis of the shaft voltage of large turbogenerators. The main interest of this study is the investigation process developed. Design/methodology/approach The analysis of the shaft voltage because of several defects is based on a two-dimensional (2D) finite element modeling. This 2D finite element model is used to determine the shaft voltage because of eccentricities or rotor short-circuit. Findings Dynamic eccentricities and rotor short circuit do not have an inherent impact on the shaft voltage. Circulating currents in the stator winding because of defects impact the shaft voltage. Originality/value The original value of this paper is the investigation process developed. This study proposes to quantify the impact of a smooth stator and then to explore the contribution of the real stator winding on the shaft voltage.

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