An Accurate Thermomechanical Model for Laser-Driven Microtransfer Printing

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Yuyan Gao ◽  
Yuhang Li ◽  
Rui Li ◽  
Jizhou Song
Keyword(s):  
Size Effect ◽  
Theoretical Basis ◽  
System Optimization ◽  
Engineering Systems ◽  
Transfer Printing ◽  
Thermomechanical Model ◽  
Element Analysis ◽  
Mechanics Model ◽  
Interfacial Fracture Mechanics ◽  
Printing Technique

A recently developed transfer printing technique, laser-driven noncontact microtransfer printing, which involves laser-induced heating to initiate the separation at the interface between the elastomeric stamp (e.g., polydimethylsiloxane (PDMS)) and hard micro/nanomaterials (e.g., Si chip), is valuable to develop advanced engineering systems such as stretchable and curvilinear electronics. The previous thermomechanical model has identified the delamination mechanism successfully. However, that model is not valid for small-size Si chip because the size effect is ignored for simplification in the derivation of the crack tip energy release rate. This paper establishes an accurate interfacial fracture mechanics model accounting for the size effect of the Si chip. The analytical predictions agree well with finite element analysis. This accurate model may serve as the theoretical basis for system optimization, especially for determining the optimal condition in the laser-driven noncontact microtransfer printing.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

scholarly journals Finite element analysis of the grain size effect on diffusion in polycrystalline materials

2014 ◽  
Vol 95 ◽  
pp. 187-191 ◽  
Author(s):  
V. Lacaille ◽  
C. Morel ◽  
E. Feulvarch ◽  
G. Kermouche ◽  
J.-M. Bergheau
Keyword(s):  
Finite Element Analysis ◽  
Grain Size ◽  
Finite Element ◽  
Size Effect ◽  
Polycrystalline Materials ◽  
Grain Size Effect ◽  
Element Analysis

Lifetime Prediction of Components Including Initiation Phase

2006 ◽  
Author(s):  
Michael Besel ◽  
Angelika Brueckner-Foit
Keyword(s):  
Input Data ◽  
Local Stress ◽  
Fatigue Loading ◽  
Computer Code ◽  
Lifetime Distribution ◽  
Element Analysis ◽  
Initiation Phase ◽  
Mechanics Model ◽  
Critical Regions ◽  
Local Stress Field

The lifetime distribution of a component subjected to fatigue loading is calculated using a micro-mechanics model for crack initiation and a fracture mechanics model for crack growth. These models are implemented in a computer code which uses the local stress field obtained in a Finite Element analysis as input data. Elemental failure probabilities are defined which allow to identify critical regions and are independent of mesh refinement. An example is given to illustrate the capabilities of the code. Special emphasis is put on the effect of the initiation phase on the lifetime distribution.

scholarly journals Theoretical and experimental research on a new rotating standing wave ultrasonic motor

2021 ◽  
Vol 2125 (1) ◽  
pp. 012047
Author(s):  
Xiaozhu Wang ◽  
Jian Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Standing Wave ◽  
Theoretical Basis ◽  
Integrated Design ◽  
Ultrasonic Motor ◽  
Element Analysis ◽  
Optimum Position ◽  
The Finite Element Analysis ◽  
Disc Spring

Abstract In this paper, a new rotating standing wave ultrasonic motor with multiple driving teeth is proposed. Using the method of adding additional teeth, the correction of the B06 surface of the ultrasonic motor vibrator is expected, the design of the optimum position of the drive tooth is realized. At the same time, a method of reducing the stiffness of the rotor is proposed, and the flexibility is met, the integrated design of the rotor and the pressure device can be realized by removing the disc spring. The accuracy of the finite element analysis is verified by the vibration test of the prototype oscillator. The finite element analysis of the main structure parameters of the influence oscillator mode and natural frequency is carried out. It provides theoretical basis for the design and machining of vibration.

The Influence of Hierarchical Decisions on Ship Design

1987 ◽  
Vol 24 (02) ◽  
pp. 131-142
Author(s):  
Warren F. Smith ◽  
Saiyid Kamal ◽  
Farrokh Mistree
Keyword(s):  
Decision Support ◽  
Design Method ◽  
System Optimization ◽  
Ship Design ◽  
Valuable Insight ◽  
Engineering Systems ◽  
Traditional Design ◽  
Computer Based ◽  
Effectiveness And Efficiency ◽  
Insight Into

The design of engineering systems involves the design of dependent subsystems and the integration of these into a whole. A typical system has the characteristics of being multileveled, multidimensional, and multidisciplined in nature. It is this complexity which causes problems for the designer in making well-founded decisions. A decision support technique has been developed which offers a structured facility for the design of the subsystems and for the modeling of the interaction which is present between subsystems. The method, employing optimization procedures, allows all aspects of the system design to be considered concurrently, to produce the "best" solution, as defined by the specifications. This is in contrast to the traditional design method, which is iterative and cyclic in nature, involving sequential reevaluation and refinement. In this paper, the effectiveness and efficiency of the decision support problem approach is demonstrated using the hierarchical characteristics of a design for a barge. The barge problem, though basic in form, is comprehensive in concept and tutorial in nature. As a formulation for "system" optimization, it uses a computer-based method for solution and illustrates the virtues of a multilevel/multidisciplinary approach to design and decision-making. It also exhibits the same characteristics and provides valuable insight into the solution of the more complex problems encountered in practical ship design.

Study on the cavity closure behavior of steel ingots during open die forging

2019 ◽  
Vol 233 (13) ◽  
pp. 2447-2457
Author(s):  
Yongchul Kwon ◽  
Sangsik Kim ◽  
Jonghun Kang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Basis ◽  
Effective Strain ◽  
Element Analysis ◽  
Large Steel ◽  
The Finite Element Analysis ◽  
Cavity Closure ◽  
Steel Ingots ◽  
Open Die Forging

The manufacturing of sound forgings from large steel ingots requires that internal cavity defects generated during the steel ingot solidification process be compressed by open die forging. The forging ratio that is generally recommended to remove internal defects in large forged products is 3S (threefold); however, the practice lacks a theoretical basis. In this study, a forging experiment and a finite element analysis were performed to investigate the correlation between the forging ratio for large steel ingots (3S) and the cavity closure behavior. First, a hot compression experiment was performed by varying the temperature and strain rate, and the flow stress data observed in the experiment was applied to the finite element analysis. In the experiment for the cogging process, the forging ratio was applied to an actual non-compressive defect material. The finite element analysis was performed using the same forging path as the forging experiment. In the cogging experiment, cavity closure was found by ultrasonic inspection at the forging ratio of 2.9S. The finite element analysis showed that the size of the cavity was significantly decreased at the forging ratio of 2.9S. A finite element analysis was also performed to investigate effective strain and hydrostatic stress at the forging ratio of 2.9S. Finally, this article provides the theoretical basis for the limitation of the internal defect size in initial materials, the threshold effective strain, and the limiting forging ratio of forged products to ensure the internal soundness of large forged products.

scholarly journals Physical features of reducing air pollution for the operating conditions of the drying drum of brick factories

2019 ◽  
Vol 135 ◽  
pp. 01034
Author(s):  
Vadim Bespalov ◽  
Gennadiy Turk ◽  
Oksana Gurova
Keyword(s):  
Air Pollution ◽  
Theoretical Basis ◽  
Block Diagram ◽  
Operating Conditions ◽  
Engineering Systems ◽  
Effective Implementation ◽  
Energy Concept ◽  
Physical Features ◽  
Relationship Of ◽  
The Relationship

The article is devoted to the study of the process of reducing air pollution in relation to the operating conditions of the drying drum of brick factories. The objectives of the work were to study and identify the physical characteristics of the process of reducing air pollution for the operating conditions of the drying drum of brick factories, for its subsequent effective implementation with the help of engineering systems. A block diagram is suggested of the physical model of the process of reducing air pollution for the considered production and technological conditions, revealing the relationship of a set of consistently and purposefully implemented stages of the cycle of dusting, using physical and energy concept as the theoretical basis. As a result of the study of the process of reducing air pollution, in relation to the operating conditions of the drying drum of brick factories operation, based on the analysis of possible solutions of the problem of dusting, physical features of the process of reducing air pollution for these production and technological conditions were identified for its subsequent effective implementation by means of engineering systems.

Finite Element Analysis of Mesh Size Effect of 3D Angle-Interlock Woven Composites Using Voxel-Based Method

2018 ◽  
Vol 25 (4) ◽  
pp. 905-920 ◽  
Author(s):  
Diantang Zhang ◽  
Guyu Feng ◽  
Mengyao Sun ◽  
Song Yu ◽  
Yuanhui Gu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Size Effect ◽  
Mesh Size ◽  
Woven Composites ◽  
Element Analysis

FINITE ELEMENT ANALYSIS OF FULL-LAYER REPAIR BASED ON IMPROVED ARTICULAR CARTILAGE MODEL

2019 ◽  
Vol 19 (08) ◽  
pp. 1940066
Author(s):  
MONAN WANG ◽  
YUANXIN JI ◽  
JIAN WANG ◽  
JUNTONG JING
Keyword(s):  
Elastic Modulus ◽  
Articular Cartilage ◽  
Stress Concentration ◽  
Mechanical Behavior ◽  
Theoretical Basis ◽  
Clinical Pathology ◽  
Mechanical State ◽  
Element Analysis ◽  
Simulation Results ◽  
Selection Of

In this paper, the tangential zone of cartilage is introduced into the fiber-reinforced model of articular cartilage. Considering the distribution content of the main fiber and the secondary fiber in the tangential layer of cartilage, the permeability and fiber stiffness of the layer are set in parallel and perpendicular directions, respectively, to more accurately reflect the mechanical behavior of cartilage. The parameters are set to reflect the mechanical behavior of the cartilage more realistically. We use a modified articular cartilage model to simulate the mechanical properties of implanted cartilage with different elastic modulus. The simulation results show that the selection of implants with different elastic modulus will affect the repair of cartilage. Appropriately increasing the elastic modulus of implanted cartilage, can increase the bearing capacity of the repaired area and reduce the stress concentration at the junction. The elastic modulus of the implant should be moderate, not too large or too small, and the damage of stress concentration on the repair surface should be considered. Through simulation, the mechanical state of the repaired cartilage under pressure can be obtained comprehensively, which provides a theoretical basis for clinical pathology.

scholarly journals Fatigue strength characterization of Al-Si cast material incorporating statistical size effect

2018 ◽  
Vol 165 ◽  
pp. 14002 ◽  
Author(s):  
Roman Aigner ◽  
Martin Leitner ◽  
Michael Stoschka
Keyword(s):  
Size Effect ◽  
Extreme Value Distribution ◽  
Ct Scanning ◽  
Element Analysis ◽  
Cast Material ◽  
Stressed Volume ◽  
Alloy Casting ◽  
Weakest Link ◽  
Testing Region ◽  
Strength Characterization

Cast aluminium components may exhibit material imperfections such as shrinkage and gas pores, or oxide inclusions. Therefore, the fatigue resistance is significantly influenced by the size and location of these inhomogenities. In this work, two different specimen geometries are manufactured from varying positions of an Al-Si-Cu alloy casting. The specimen geometries are designed by means of shape optimization based on a finite element analysis and exhibit different highly-stressed volumes. The numerically optimized specimen curvature enforces a notch factor of only two percent. To enable the evaluation of a statistical size effect, the length of the constant testing region and hence, the size of the highly-stressed volume varies by a ratio of one to ten between the two specimen geometries. Furthermore, the location of the crack initiation is dominated by the comparably greatest defects in this highly-stressed volume, which is also known as Weibull’s weakest link model. The crack initiating defect sizes are evaluated by means of light microscopy and modern scanning electron microscope methods. Finally, the statistical size effect is analysed based on the extreme value distribution of the occurring defects, whereby the size and location of the pores is non-destructively obtained by computed tomography (CT) scanning. This elaborated procedure facilitates a size-effect based methodology to study the defect distribution and the associated local fatigue life of CPS casted Al-Si lightweight components.

Sign in / Sign up

Export Citation Format

Share Document