Three-dimensional Process Simulation Research Articles

Real single grain grinding FEM simulation for case-hardened steel based on equivalent contact area analysis

Abstract Grinding is an indispensable phase in the gear production chain as it allows very stringent requirements characteristic of the automotive sector to be satisfied. The main goal of this finishing process is to ensure compliance with the surface integrity and dimensional tolerance specifications of the product. A single-grain grinding FEM model has been implemented to predict grinding load values based on real grain geometry using a set of Johnson & Cook coefficients able to represent the flow stress curve of a typical gear case-hardened steel 27MnCr5. Grain geometry acquired through computed tomography was imported into three-dimensional process simulation software DEFORM-3D. As the use of real grain geometry leads to time-consuming simulations, an equivalent defined geometry grain was implemented to compare cutting behavior and calculate maximum force values through real contact area analysis under the same process parameters. Calculated loads were subsequently compared with experimental results, showing good agreement with a maximum percentage difference less than 13% for two different grain geometries. Grinding force measurements were performed in a single-grain configuration on a CNC surface grinding machine adopting a wheel speed of 384 rad/s, feed rate of 8.6 mm/s and a depth of cut of 0.1 mm.

Towards numerical prediction of flow-induced fiber displacements during wet compression molding (WCM)

Wet compression molding (WCM) provides large-scale production potential for continuous fiber-reinforced structural components due to simultaneous infiltration and draping during molding. Due to thickness-dominated infiltration of the laminate, comparatively low cavity pressures are sufficient – a considerable economic advantage. Experimental and numerical investigations prove strong mutual dependencies between the physical mechanisms, especially between resin flow (mold filling) and textile forming (draping), similar to other liquid molding techniques (LCM). Although these dependencies provide significant benefits such as improved contact, draping and infiltration capabilities, they may also lead to adverse effects such as flow-induced fiber displacement. To support WCM process and part development, process simulation requires a fully coupled approach including the capability to predict critical process effects. This work aims to demonstrate the suitability of a macroscopic, fully coupled, three-dimensional process simulation approach, to predict the process behavior during WCM, including flow-induced fiber displacements. The developed fluid model is superimposed to a suitable 3D forming model, which accounts for the deformation mechanisms including non-linear transverse compaction behavior. A strong Fluid-Structure-Interaction (FSI) enforced by Terzaghi’s law is applied to assess flow-induced fiber displacements during WCM within a porous UD-NCF stack in a homogenized manner. Accordingly, resulting local deformations are considered within the pressure field. All constitutive equations are formulated with respect to fiber deformation under finite strains. Results of a parametric study underline the relevance of contact conditions within the dry and infiltrated stack. The numerically predicted results are benchmarked and verified using both own and available experimental results from literature.

A 3D process simulation model for wet compression moulding

Wet Compression Moulding (WCM) provides large-scale production potential for continuously fibre-reinforced structural components due to simultaneous infiltration and draping during moulding. Due to thickness-dominated infiltration of the laminate, comparatively low cavity pressures are sufficient - a considerable economical advantage. Similar to other Liquid Compression Moulding (LCM) processes, forming and infiltration strongly interact during process. However, the degree of forming is much higher in WCM, which disqualifies a sequential modelling approach. This is demonstrated in this work via experimental characterisation of the interaction between compaction and permeability of a woven fabric and by trials with a transparent double dome geometry, which facilitates an in situ visualization of fluid progression during moulding. In this light, and in contrast to existing form filling approaches, a forming-inspired, three-dimensional process simulation approach is presented containing two fully-coupled macroscopic forming and fluid-submodels. The combined model is successfully benchmarked using experimental double dome trials with transparent tooling.

Basic models and approximation for the engineering description of the kinetics of the oxide layer of steel in a flow of heavy liquid metal coolant under various oxygen conditions

The article presents the results of corrosion processes, kinetics and changes in the oxide layer modeling using MASKA-LM software complex. The complex is intended for a numerical simulation of three-dimensional non-stationary processes of mass transfer and interaction of impurity components in a heavy liquid metal coolant (HLMC: lead, lead-bismuth). The software complex is based on the numerical solution of coupled three-dimensional equations of hydrodynamics, heat transfer, formation and convective-diffusive transport of chemically interacting components of impurities. Examples of calculations of mass transfer processes and interaction of impurity components in HLMC, formation of protective oxide films on the surfaces of steels are given to justify the coolant technology.

Dependence of three-dimensional bottleneck barrier height minimum on threshold voltage fluctuated by ion implantation of source and drain extensions in silicon-on-insulator triple-gate fin-type field-effect transistors

We have investigated the threshold voltage (Vth) fluctuated by ion implantation (I/I) of the source and drain extensions for a leading-edge variability-tolerant device structure using a three-dimensional (3D) process and device simulations. We have previously reported that the fluctuated Vth is characterized by the variation of the minimum value of the 3D bottleneck barrier height (BBH3D,min) of electrostatic potential from the source contact to the corresponding bottleneck points in the entire device. Standardized multiple regression analysis indicated that the 3D position where BBH3D,min exists (BBP3D,min) has only a weak correlation with the Vth. The effect of the BBP3D,min on the Vth is not significantly large; therefore, the Vth can almost be explained by only the value of BBH3D,min over the entire Vth region, despite the drain bias condition.

Direct numerical simulation of sublimating ice particles

A thermodynamically consistent numerical framework for the simulation of three-dimensional sublimation processes of ice at temperatures below the triple point and low pressure is presented. To this end, a novel description of the local thermodynamic equilibrium of frozen water (ice) and a mixture of water vapour and an inert gas is derived, where anisotropic surface energy densities can be considered. A new correlation for the diffusion coefficient of water vapour in nitrogen is proposed based on equilibrium molecular dynamics simulations. The simulation results are in excellent agreement with experimentally obtained sublimation rates.

Three-dimensional exploration of the origin of threshold voltage fluctuation of silicon-on-insulator triple-gate fin-type field-effect transistors caused by ion implantation to source and drain extensions

The origin of the Vth fluctuation induced by ion implantation (I/I) into the source and drain extensions (SDEs) of triple-gate (tri-gate) fin-type field-effect transistors has been three-dimensionally explored by both three-dimensional (3D) process and device simulations. The 3D electrostatic potential distributions in the whole Si channel fin are analyzed, and it is confirmed that the 3D electrostatic potential distribution of the lowest Vth sample is more undulated than that of the highest Vth sample due to implanted arsenic (As+) ions to the SDEs irrespective of the drain bias condition. We found also that the minimum of bottleneck barrier heights (BBHs) in the Si whole channel fin, which is called BBH3D,min, is strongly correlated with the Vth, and therefore is a strong indicator to study the Vth of the device. It now became obvious that the origin of the SDE I/I-induced Vth fluctuation is a variation of BBH3D,min in the whole channel for the first time. The obtained results are beneficial for the research and development of such future devices.

Origin of threshold voltage fluctuation caused by ion implantation to source and drain extensions of silicon-on-insulator triple-gate fin-type field-effect transistors using three-dimensional process and device simulations

The threshold voltage (Vth) fluctuation induced by ion implantation (I/I) in the source and drain extensions (SDEs) of a silicon-on-insulator (SOI) triple-gate (Tri-Gate) fin-type field-effect transistor (FinFET) was analyzed by both three-dimensional (3D) process and device simulations collaboratively. The origin of the Vth fluctuation induced by the SDE I/I is basically a variation of a bottleneck barrier height (BBH) due to implanted arsenic (As+) ions. In particular, a very low and broad Vth distribution in the saturation region is due to percolative conduction in addition to the BBH variation. Moreover, it is surprisingly found that the Vth fluctuation is mostly characterized by the BBH of only a top surface center line of a Si fin of the device. Our collaborative approach by 3D process and device simulations is dispensable for the accurate investigation of variability-tolerant devices. The obtained results are beneficial for the research and development of such future devices.

Numerical Simulation of Three-Dimensional Processes of the Interaction of Elastic-Plastic Bodies with the Product of Detonation in Eiler Variables

Numerical Simulation of Three-Dimensional Processes of the Interaction of Elastic-Plastic Bodies with the Product of Detonation in Eiler Variables

Very low and broad threshold voltage fluctuation caused by ion implantation to silicon-on-insulator triple-gate fin-type field effect transistor using three-dimensional process and device simulations

The threshold voltage (Vth) fluctuation induced by the ion implantation to the source and drain extensions (SDE) of a silicon-on-insulator (SOI) triple-gate (tri-gate) fin-type field-effect transistor (FinFET) was analyzed for the first time with the use of realistic positional information of discretely doped ions by both three-dimensional (3D) process and device simulations. Interestingly, it was found that the Vth fluctuation induced by SDE ion implantation has a very low and broad distribution on the low-Vth side even in the case of a robust device structure such as SOI tri-gate FinFET. Furthermore, for the first time, it was quantitatively demonstrated using a proposed cluster percolation model that the origin of the very low and broad Vth fluctuation is the conductive percolation among unintentionally doped ions in the channel region of the device. These results would contribute to the realization of robust transistors.

The Site Visualization and Closed-Loop Control for 3D Assembly Process

With the rapid development of 3D CAD technology, 3D assembly process is playing an important role in the on-site assembly. A closed-loop control method and three-dimensional site visualization technology site is presented. The methodology takes into account CAD design stage, assembly process design, site assembly and site inspection. The method includes three key technologies: the verification process technology of three-dimensional assembly process, optimization and process simulation techniques of site assembly, closed-loop control technology of assembly process quality inspection. Finally, the method and technology has applied in the actual assembly, and achieved good results.

Numerical analysis of Al vapour effects in gas metal arc welding of Al alloys

Using an in-house three-dimensional (GMAW) process simulation tool, the effects of Al vapour in the arc welding of aluminium alloys for various welding currents have been studied. The mathematical model, which takes into account the effects of metal vapour, is described. A bead-on-Al-plate problem is then modelled, with and without consideration of the Al vapour for various welding currents. The effects of the Al vapour on the energy flow of the system and the resulting weld profile are examined. The calculated plasma temperatures are compared with measured temperatures. The change of heat input to the workpiece due to the presence of Al vapour is examined. Finally, the calculated weld profiles with and without consideration of Al vapour are compared with actual weld profiles. It is found that the presence of Al vapour reduces the arc temperature and the weld depth significantly.

Research on Simulation of Complex Distillation System for Biomass Fuel Ethanol Based on Virtual Assembly

Virtual assembly was introduced in the chemical process simulation, and the method of virtual assembly for common chemical process was studied. The process of biomass fuel ethanol was analyzed which is combined by the first-grade distillation system in industrial ethanol production and the salt-added extractive distillation system in fuel ethanol production, and the scene graph structure was established. According to the assembly characteristics of the chemical process, the assembly equipment model was designed and constructed. The assembly points were added, and the assembly, simulation and transitive properties of the assembly points were defined. The 1+1and 1+n universality assembly method was proposed. By choosing unit equipment freely to assembly, the complex distillation system was realized. Results have shown that the assembly effect was good and accuracy, the method was proved correct and feasible. It is of great significance in the visual design of chemical process, digital construction of chemical plant and development of three-dimensional (3D) chemical process simulation technology.

Analysis of energy flow in gas metal arc welding processes through self-consistent three-dimensional process simulation

A self-consistent three-dimensional gas metal arc welding (GMAW) modeling tool is used to analyze energy flow in an aluminum GMAW process. The mathematical model employed in the tool considers energy, momentum and mass transfer between three interacting domains: the filler wire (anode), the arc plasma, and the workpiece (cathode), which includes the molten pool. The mass, momentum and heat transfer associated with the droplets are also considered. The tool is used to model a bead-on-Al-plate problem and validated by comparing predicted and measured weld profiles. The energy input, transformation, transfer, dissipation due to different physical processes are calculated and analyzed to understand the energy structure and flow in the system for a range of welding currents. The energy efficiency, which is the ratio of the energy consumed in melting the metal to the total energy input into the system, is calculated to study the effect of current input on the system efficiency. The findings from the study provide guidance to engineers in designing GMAW schedules to achieve quality welds with good energy efficiency.

The Visualization Manufacturing System Research Based on Three-Dimensional Process Model of Full Information

Three-dimensional visualization manufacturing technology based on the model defined is an emerging technology in the digital manufacturing of modern aviation, and that is a development trend of air-crafts, three-dimensional assembly process design. The technology mainly through the integration of the three-dimensional process design and process simulation systems, complete the connection of instructions、information and data which generated from design and simulation stage, and through integrating with MES, pass the completed design information of process to the production site to achieve visual assembly, get through a technology roadmap of product design and process design and on-site visualization assembly of model-based definition. Solved the difficult problem of the digitizing processing information obtained from the traditional two-dimensional drawings, and improved the overall efficiency of the manufacturing cycle.

Technology computer-aided design simulation study for a strained InGaAs channel n-type metal-oxide-semiconductor field-effect transistor with a high-k dielectric oxide layer and a metal gate electrode

The stress distributions in the InGaAs channel regions of strained InGaAs metal-oxide-semiconductor (MOS) field-effect transistors with high-k dielectric layer, metal gate, and InGaAs alloy souce/drain (S/D) stressors were studied with three-dimensional process simulations. It was shown that the geometric effects, such as channel width and length, could impact the achievable transistor performance gains. In this work, high-performance III-V MOS devices were achieved by stressors, such as S/D stressors, with the InGaAs alloy material. The resulting mobility improvement was analyzed by the Monte Carlo simulations. Tensile stress along the transport direction was found to dominate mobility gain while narrower devices (<1 μm), and a decrease of tensile stress along the channel direction contributed to a decrease in mobility gain owing to the decreasing width. This work helps the future III-V-based MOS device design and demonstrates that strain engineering is important for future nanoscale device technology.

Debris flow simulation-oriented three-dimensional scenery modeling and rendering

3D (three-dimensional) process simulation is currently one of the most challenging fields of research on debris flow. Large scale terrain rendering is the most basic task of 3D scenery construction in debris flow simulation. As the major trigger for debris flow, rainfall will substantially enhance the realistic sense. Terrain and rainfall rendering in 3D debris flow simulations poses great challenges for numerical computation and graphical processing capability. In this paper, we propose to integrate GPU technology, LoD algorithms, and particle systems to realize 3D scenery modeling and rendering. The real-time LoD-based terrain modeling and rendering algorithm is presented first, and then a particle system-based rainfall scenery rendering method is implemented. Experimental results demonstrate that the 3D scenery rendered with the proposed approach exhibits sound performance and fair visual effects, which lays a solid foundation for the whole process simulation of debris flow disasters.

Nanometer-Scale Oxide Thin Film Transistor with Potential for High-Density Image Sensor Applications

The integration of electronically active oxide components onto silicon circuits represents an innovative approach to improving the functionality of novel devices. Like most semiconductor devices, complementary-metal-oxide-semiconductor image sensors (CISs) have physical limitations when progressively scaled down to extremely small dimensions. In this paper, we propose a novel hybrid CIS architecture that is based on the combination of nanometer-scale amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) and a conventional Si photo diode (PD). With this approach, we aim to overcome the loss of quantum efficiency and image quality due to the continuous miniaturization of PDs. Specifically, the a-IGZO TFT with 180 nm gate length is probed to exhibit remarkable performance including low 1/f noise and high output gain, despite fabrication temperatures as low as 200 °C. In particular, excellent device performance is achieved using a double-layer gate dielectric (Al₂O₃/SiO₂) combined with a trapezoidal active region formed by a tailored etching process. A self-aligned top gate structure is adopted to ensure low parasitic capacitance. Lastly, three-dimensional (3D) process simulation tools are employed to optimize the four-pixel CIS structure. The results demonstrate how our stacked hybrid device could be the starting point for new device strategies in image sensor architectures. Furthermore, we expect the proposed approach to be applicable to a wide range of micro- and nanoelectronic devices and systems.

Simulation of a nanoscale strained Si NMOSFET with a silicon–carbon alloy stressor

The stress distribution in the silicon (Si) channel regions of silicon–carbon (SiC) source/drain negative-metal-oxide semiconductor field-effect transistors (NMOSFETs) with various widths was studied using three-dimensional (3D) process simulations. The drive current enhancement in wide devices was dominated by the tensile stress along the transport and vertical directions. Stress along the width (transverse) direction has the least effect on the drain current in wide devices. Stress along the width direction in narrow devices was found to degrade the drive current gain and cannot be neglected. In addition, a reduction of device width was found to reduce the drive current gain due to the presence of less compressive stress in the vertical direction in the device channel, caused by the shrinking SiC regions. The impact of width on performance improvements such as drive current mobility gain was analyzed using Technology Computer-Aided Design (TCAD) simulations.

On the assessment of various implants using 3D TCAD for FinFETs

This work deals with the junction and channel optimization on FinFET devices. The main objective was to show feasibility of a three-dimensional (3D) process simulation within the context of optimization of the device design and the underlying fabrication processes. The 3D simulation process flow is based on the development of the SOI based FinFET devices at Infineon. Similar to real devices, important 3D geometrical features, such as corner roundings and 3D facets have been introduced into the simulation setup, which is based on commercially available 3D process simulation software (Taurus 3D). The influence of various unit process steps, such as channel implant, and LDD implant on the electrical performance of the devices have been evaluated. Beside the successful demonstration of a functional 3D process simulation flow, detailed issues of process and device simulation methodology such as the usage of different dopant diffusion and mobility models are assessed. Finally, a comparison of the simulation results with electrical measurement data is performed which fairly shows excellent agreement.