A Contribution to the Simulation of Molded Micro Components and Systems With Regard to the Grain Structure

2008 ◽  
Author(s):  
Albert Albers ◽  
Hans-Georg Enkler ◽  
Pablo Leslabay
Keyword(s):  
Stress Distribution ◽  
Grain Structure ◽  
The Finite Element Method ◽  
Component Level ◽  
Grain Structures ◽  
Micro Parts ◽  
Transfer Behavior ◽  
Manufacturing Techniques ◽  
The Individual ◽  
Multi Body

Experimental work for characterizing materials’ properties as well as components’ and systems’ behaviors have to be supplemented by numerical analyses when regarding micro components and systems. In order to accomplish a complete possibilities’ overview for micro machines these analyses should cover both component and system issues. On a component level, established macroscopic approaches are extended by methods that allow the consideration of components’ grain structures influence, including possible superficial and internal defects. Because of technological restrictions, especially when applying miniaturized conventional manufacturing techniques, shape and material deviations cannot be scaled down in the same dimensions like micro parts. Thus, high tolerances accepted for the individual components and their effects on the expected transfer behavior of the whole system are taken primarily into account. This paper presents approaches for the simulation of micro components and systems using the Finite Element Method and Multi Body Simulation. Methods to overcome the above mentioned issues will be shown, as well as the effects of grain structure on the stress distribution in the individual components. Some effects over the system’s behavior of this inhomogeneous stress distribution are also discussed.

Simulation of Molded Micro Components and Systems With Regard to the Grain Structure

2008 ◽  
Author(s):  
Albert Albers ◽  
Hans-Georg Enkler ◽  
Pablo Leslabay
Keyword(s):  
Stress Distribution ◽  
Ad Hoc ◽  
Grain Structure ◽  
Element Analysis ◽  
Micro Parts ◽  
Manufacturing Techniques ◽  
The Individual ◽  
Multi Body ◽  
Term Objective

Miniaturization of macroscopic mechanical systems enables the opening of new areas of application for micro technological systems. Because of actual technological restrictions, especially when applying miniaturized conventional manufacturing techniques, shape and material deviations can not be decreased as strong as the dimensions of the micro parts are reduced. A long-term objective in the development of such systems is to ensure functional capability by adoption of appropriate design measures that compensate these deviations. This work presents methods based on computer simulation that contribute to achieve this objective. One method is based on the utilization of ad-hoc modified and simplified Finite Element Analysis techniques, which now regards some issues of interest from Multi Body Simulation. The introduction of this method also allows studying the behavior of the components and the system with regard to the component’s internal grain structure. When the focus is directed to the robustness or the reliability of the system, another method is presented that is based on a hybrid FEA-MBS solver. It shows better performance both on parameters modeling capability and computational efficiency. Methods to overcome the above mentioned issues, as well as the effects of grain structure on the stress distribution in the individual components will be presented. Some effects affecting the system’s behavior because of this inhomogeneous stress distribution are also discussed. Finally, an investigation about the consequences of having internal defects within individual components is conducted.

scholarly journals A Novel Approach to Predict the Process-Induced Mechanical Behavior of Additively Manufactured Materials

2021 ◽  
Author(s):  
Andreas Kergaßner ◽  
Johannes A. Koepf ◽  
Matthias Markl ◽  
Carolin Körner ◽  
Julia Mergheim ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Yield Criterion ◽  
Grain Structure ◽  
The Finite Element Method ◽  
Present Contribution ◽  
Plastic Properties ◽  
Novel Approach ◽  
Grain Structures ◽  
Selective Electron Beam Melting ◽  
Yield Loci

AbstractThe grain structure and texture of additively manufactured materials depend strongly on the local temperature gradients during the solidification of the material. These grain structures and textures influence the mechanical behavior, ranging from isotropy to transversal and orthotropic symmetry. In the present contribution, a cellular automaton is used to model the grain growth during selective electron beam melting. The resulting grain structures and textures serve as input for a mesoscopic mechanical model. The mechanical behavior on the mesoscale is modeled by means of gradient-enhanced crystal plasticity, applying the finite element method. Computational homogenization is applied to determine the resulting macroscopic elastic and plastic properties of the additively manufactured metals. A general orthotropic yield criterion is identified by means of the initial yield loci computed with mesoscopic simulations of representative volume elements. The numerical results are partly validated with experimental data.

scholarly journals Scalable Multiport Converter Structure for Easy Grid Integration of Alternate Energy Sources for Generation of Isolated Voltage Sources for MMC

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1779
Author(s):  
Syed Rahman ◽  
Irfan Khan ◽  
Khaliqur Rahman ◽  
Sattam Al Otaibi ◽  
Hend I. Alkhammash ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Energy Resources ◽  
Energy Sources ◽  
Renewable Energy Resources ◽  
Component Level ◽  
Storage Devices ◽  
Multiport Converter ◽  
Detailed Simulation ◽  
The Individual

This paper presents a novel, scalable, and modular multiport power electronic topology for the integration of multiple resources. This converter is not only scalable in terms of the integration of multiple renewable energy resources (RES) and storage devices (SDs) but is also scalable in terms of output ports. Multiple dc outputs of a converter are designed to serve as input to the stacking modules (SMs) of the modular multilevel converter (MMC). The proposed multiport converter is bidirectional in nature and superior in terms of functionality in a way that a modular universal converter is responsible for the integration of multiple RES/SDs and regulates multiple dc output ports for SMs of MMC. All input ports can be easily integrated (and controlled), and output ports also can be controlled independently in response to any load variations. An isolated active half-bridge converter with multiple secondaries acts as a central hub for power processing with multiple renewable energy resources that are integrated at the primary side. To verify the proposed converter, a detailed design of the converter-based system is presented along with the proposed control algorithm for managing power on the individual component level. Additionally, different modes of power management (emulating the availability/variability of renewable energy sources (RES)) are exhibited and analyzed here. Finally, detailed simulation results are presented in detail for the validation of the proposed concepts and design process.

The Effect of Thermal Prestress on the Deformation of Micromirror Chip Embedded with Through-Silicon Vias

2011 ◽  
Vol 462-463 ◽  
pp. 563-568 ◽  
Author(s):  
Meng Kao Yeh ◽  
Chun Lin Lu
Keyword(s):  
Stress Distribution ◽  
Room Temperature ◽  
Thermal Loading ◽  
Heat Transfer Analysis ◽  
Processing Temperature ◽  
Temperature Decrease ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Through Silicon Vias ◽  
Silicon Vias

The thermal expansion mismatch problem for a chip due to temperature decrease from processing temperature to room temperature may cause residual stress inside the chip structure. The thermal prestress accumulated and may affect the chip reliability when the chip was subjected to the thermal loading again. In this paper, the effect of thermal prestress on the micromirror chip embedded with copper through-silicon vias (TSVs) was investigated by the finite element method. In analysis, the micromirror chip embedded with TSVs was analyzed first under thermal loading which resulted from temperature decrease between the stress free processing temperature and room temperature. This process produced a thermal prestress in the micromirror chip. The chip was then subjected to a heat source at the bottom while in operation and the heat transfer analysis was used to simulate this situation. Finally, the thermal stress analysis was carried out to obtain the deformation and the stress distribution in the chip. The results show that the thermal prestress had strong effect on the chip reliability and should be reduced as much as possible. This paper proposed a three steps analysis method to obtain the deformation and the stress distribution in the chip, in which the effect of thermal prestress on the chip reliability was evaluated effectively.

Engine Fleet-Management: The Use of Digital Twins From a MRO Perspective

2017 ◽  
Author(s):  
Joern Kraft ◽  
Stefan Kuntzagk
Keyword(s):  
Multilevel Models ◽  
Operating Cost ◽  
Maintenance Cost ◽  
Fleet Management ◽  
Component Level ◽  
The Real ◽  
Digital Twin ◽  
Digital Twins ◽  
The Individual ◽  
Life Consumption

Engine operating cost is a major contributor to the direct operating cost of aircraft. Therefore, the minimization of engine operating cost per flight-hour is a key aspect for airlines to operate successfully under challenging market conditions. The interaction between maintenance cost, operating cost, asset value, lease and replacement cost describes the area of conflict in which engine fleets can be optimized. State-of-the-art fleet management is based on advanced diagnostic and prognostic methods on engine and component level to provide optimized long-term removal and work-scoping forecasts on fleet level based on the individual operation. The key element of these methods is a digital twin of the active engines consisting of multilevel models of the engine and its components. This digital twin can be used to support deterioration and failure analysis, predict life consumption of critical parts and relate the specific operation of a customer to the real and expected condition of the engines on-wing and at induction to the shop. The fleet management data is constantly updated based on operational data sent from the engines as well as line maintenance and shop data. The approach is illustrated along the real application on the CFM56-5C, a mature commercial two-spool high bypass engine installed on the Airbus A340-300. It can be shown, that the new methodology results in major improvements on the considered fleets.

scholarly journals Microstructural Transitions during Powder Metallurgical Processing of Solute Stabilized Nanostructured Tungsten Alloys

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 159
Author(s):  
Nicholas Olynik ◽  
Bin Cheng ◽  
David J. Sprouster ◽  
Chad M. Parish ◽  
Jason R. Trelewicz
Keyword(s):  
Extreme Environments ◽  
High Energy ◽  
Grain Structure ◽  
Coarse Grained ◽  
Ultrafine Grain ◽  
Grain Boundary Engineering ◽  
Carbon Impurities ◽  
Grain Structures ◽  
Metallurgical Processing ◽  
Size Population

Exploiting grain boundary engineering in the design of alloys for extreme environments provides a promising pathway for enhancing performance relative to coarse-grained counterparts. Due to its attractive properties as a plasma facing material for fusion devices, tungsten presents an opportunity to exploit this approach in addressing the significant materials challenges imposed by the fusion environment. Here, we employ a ternary alloy design approach for stabilizing W against recrystallization and grain growth while simultaneously enhancing its manufacturability through powder metallurgical processing. Mechanical alloying and grain refinement in W-10 at.% Ti-(10,20) at.% Cr alloys are accomplished through high-energy ball milling with transitions in the microstructure mapped as a function of milling time. We demonstrate the multi-modal nature of the resulting nanocrystalline grain structure and its stability up to 1300 °C with the coarser grain size population correlated to transitions in crystallographic texture that result from the preferred slip systems in BCC W. Field-assisted sintering is employed to consolidate the alloy powders into bulk samples, which, due to the deliberately designed compositional features, are shown to retain ultrafine grain structures despite the presence of minor carbides formed during sintering due to carbon impurities in the ball-milled powders.

scholarly journals The role of early prosthetic help in the system of rehabilitation of the military personnel with military trauma: organizational, legal and methodical aspects

2018 ◽  
Vol 20 (2) ◽  
pp. 40-47
Author(s):  
V G Suslyaev ◽  
O N Vladimirova ◽  
K K Shcherbina ◽  
A V Sokurov ◽  
Yu I Zhdanov ◽  
...  
Keyword(s):  
Artificial Limbs ◽  
Individual Choice ◽  
Disabled People ◽  
Express Method ◽  
Full Contact ◽  
Military Trauma ◽  
Recovery Treatment ◽  
Manufacturing Techniques ◽  
The Individual ◽  
And Training

The role and the place of early use of technical means of rehabilitation in the system of complex rehabilitation of patients and disabled people owing to a military trauma is considered. Need of early providing the needing persons with technical means of rehabilitation is proved during recovery treatment, including before establishment by him of disability and formation of the individual program of rehabilitation and an abilitation of disabled people. The efficiency of the developed non-plaster technology of prosthetics manufacturing techniques of artificial limbs of the lower extremities is proved by express method, options of her execution are offered. The first option of production of products on this technology consists in use of polymeric silicone covers and the water-hardening polymeric bandage directly on the patient’s stump. The second option of prosthetics is applied at some defects and diseases of a stump excluding application of silicone covers and full contact individual reception sleeves. For this purpose at production of medical and training artificial limbs of a shin and hip adjustable demountable reception sleeves from thermolayers for right-and left-side amputating defects are used. These options of prosthetics by express method are innovative, are aimed at early rendering the prosthetic and orthopedic help to patients with amputating defects. At production of artificial limbs on these technology domestic materials, modular and not modular accessories are used. The modular complete set of medical and training artificial limbs provides fast and individual setting up the scheme of construction, the individual choice of combinations of functional elements taking into account group of physical activity of the patient, a possibility of replacement of a reception sleeve and any of product elements without withdrawal of an artificial limb at the user. In need of service of a product, for example repair, replacement of the module (artificial foot, a knee) there is no requirement of urgent production of a similar design. Adjustable reception sleeves for primary artificial limbs of a shin and hip in the form of a standard series and moisture-curing bandage can add the list of products of medical appointment in laying for expansion of medical institutions during the special period.

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