Research on Laser Induced Thermal-Crack Propagation Cutting Silicon Wafer

2012 ◽  
Vol 628 ◽  
pp. 211-216 ◽  
Author(s):  
C.Y. Zhao ◽  
Hong Zhi Zhang ◽  
Y. Wang
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Silicon Wafer ◽  
Optical Microscope ◽  
Propagation Mechanism ◽  
Thermal Crack ◽  
Technological Parameters ◽  
Material Loss ◽  
Finite Element Software ◽  
The Impact

Laser molten cutting silicon wafer was focused more recently, but this method has the material loss disadvantage. So this paper indicates the finite element simulation and experiments of cutting silicon wafer with YAG laser induced thermal-crack propagation. A theoretical model of a thermal laser shock method for separation of the silicon wafer is developed, and the fracture propagation mechanism is studied by the stress fields using finite element software ABAQUS. Optical microscope and laser scan confocal microscope (LSCM) photographs of the separation surface and path are obtained to examine the cutting quality. The impact of technological parameters on the cutting quality is studied and the optimum processing parameters are presented in the paper.

Curve Cutting ZrO2 Ceramic and Cooling Lower Surface Cutting Silicon Wafer with Laser Induced Thermal-Crack Propagation

2014 ◽  
Vol 711 ◽  
pp. 222-226
Author(s):  
Chun Yang Zhao ◽  
Hong Zhi Zhang ◽  
Li Jun Yang ◽  
Yang Wang
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Silicon Wafer ◽  
Fracture Mechanism ◽  
Brittle Materials ◽  
Lower Surface ◽  
Thermal Crack ◽  
Surface Absorption ◽  
Finite Element Software

In laser induced thermal crack propagation (LITP) cutting brittle materials, according to the laser absorption ability, materials are divided into the body absorption and surface absorption. This paper indicates the fracture mechanism of LITP cutting surface absorption brittle materials. The crack extension appears in the lower surface firstly in this stress distribution state, then the crack extends to the upper surface and the laser scanning direction with the LITP cutting. The stress field of cutting ZrO2 ceramic is studied by finite element software ANSYS. The crack propagation process of cutting silicon wafer is studied by finite element software ABAQUS. According to the fracture mechanism, the curve cutting the ZrO2 ceramic experiments and the cooling lower surface cutting the silicon wafer experiments are carried out in this paper. Optical microscope and laser scan confocal microscope (LSCM) photographs of the curve path the ZrO2 ceramic and separation surface cutting the silicon wafer are obtained to examine the cutting quality. The quality of the curve path is very good. The quality of the separation surface in cutting the silicon wafer with the cooling lower surface is better than conventional environment.

The unbiased propagation mechanism in laser cutting silicon wafer with laser induced thermal-crack propagation

2019 ◽  
Vol 125 (7) ◽  
Author(s):  
Xiaoliang Cheng ◽  
Lijun Yang ◽  
Maolu Wang ◽  
Yecheng Cai ◽  
Yang Wang ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Silicon Wafer ◽  
Laser Cutting ◽  
Propagation Mechanism ◽  
Thermal Crack

scholarly journals Delamination Buckling and Crack Propagation Simulations in Fiber-Metal Laminates Using xFEM and Cohesive Elements

2018 ◽  
Vol 8 (12) ◽  
pp. 2440 ◽  
Author(s):  
Davide De Cicco ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Hybrid Composites ◽  
Cohesive Elements ◽  
Zone Method ◽  
Fiber Metal Laminates ◽  
Finite Element Software ◽  
Numerical Predictions ◽  
Delamination Buckling ◽  
Fiber Metal

Simulation of fracture in fiber-reinforced plastics (FRP) and hybrid composites is a challenging task. This paper investigates the potential of combining the extended finite element method (xFEM) and cohesive zone method (CZM), available through LS-DYNA commercial finite element software, for effectively modeling delamination buckling and crack propagation in fiber metal laminates (FML). The investigation includes modeling the response of the standard double cantilever beam test specimen, and delamination-buckling of a 3D-FML under axial impact loading. It is shown that the adopted approach could effectively simulate the complex state of crack propagation in such materials, which involves crack propagation within the adhesive layer along the interface, and its diversion from one interface to the other. The corroboration of the numerical predictions and actual experimental observations is also demonstrated. In addition, the limitations of these numerical methodologies are discussed.

scholarly journals Collapse Analysis of a Transmission Tower-Line System Induced by Ice Shedding

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaxiang Li ◽  
Biao Wang ◽  
Jian Sun ◽  
Shuhong Wang ◽  
Xiaohong Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Transmission Lines ◽  
Progressive Collapse ◽  
Element Model ◽  
Transmission Tower ◽  
Line System ◽  
Finite Element Software ◽  
Transmission Towers ◽  
Ice Shedding ◽  
The Impact

Ice shedding causes transmission lines to vibrate violently, which induces a sharp increase in the longitudinal unbalanced tension of the lines, even resulting in the progressive collapse of transmission towers in serious cases, which is a common ice-based disaster for transmission tower-line systems. Based on the actual engineering characteristics of a 500 kV transmission line taken as the research object, a finite element model of a two-tower, three-line system is established by commercial ANSYS finite element software. In the modeling process, the uniform mode method is used to introduce the initial defects, and the collapse caused by ice shedding and its influencing parameters are systematically studied. The results show that the higher the ice-shedding height is, the greater the threat of ice shedding to the system; furthermore, the greater the span is, the shorter the insulator length and the greater the dynamic response of the line; the impact of ice shedding should be considered in the design of transmission towers.

Laser beam induced thermal-crack propagation for asymmetric linear cutting of silicon wafer

2019 ◽  
Vol 120 ◽  
pp. 105765 ◽  
Author(s):  
Xiaoliang Cheng ◽  
Lijun Yang ◽  
Maolu Wang ◽  
Yecheng Cai ◽  
Yang Wang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Crack Propagation ◽  
Silicon Wafer ◽  
Thermal Crack

Analyze the Impact of the Thin-Walled Hollow Pier by Construction of Reservoir

2013 ◽  
Vol 438-439 ◽  
pp. 1262-1264
Author(s):  
Ke Dong Tang ◽  
Feng Gui Jin
Keyword(s):  
Finite Element ◽  
Realistic Model ◽  
Finite Element Software ◽  
Before And After ◽  
Reservoir Construction ◽  
Thin Walled ◽  
The Impact

The river dam intends to build at 280m downstream of a built bridge. This paper, using ANSYS finite element software, establishes a rational and realistic model to analyze the influence of the reservoir construction on the thin-walled hollow pier of built bridge. The variation of the stress of the bridge thin-walled hollow pier before and after impounding of the reservoir is given out, which can be as a guidance for future reinforcing the thin-walled hollow pier.

Analysis of Influence of Design Parameters on Ultimate Bearing Capacity of the Steel Spatial Tubular Joint

2011 ◽  
Vol 243-249 ◽  
pp. 294-297
Author(s):  
Rui Tao Zhu
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bearing Capacity ◽  
Plate Thickness ◽  
Ultimate Bearing Capacity ◽  
Design Parameters ◽  
Finite Element Software ◽  
Computing Model ◽  
Tubular Joint ◽  
The Impact

Utilizing general finite element software ANSYS, the finite element computing model of the steel spatial tubular joint is built, which is used to analyze the mechanical properties under dead loads through changing its design parameters. According to the obtained and compared consequences, the different design parameters including stiffening ring thickness, cross-shaped ribbed plate thickness and stiffening ring length exert different influence on ultimate bearing capacity of the steel spatial tubular joint. Specifically, the ultimate bearing capacity under dead loads is affected by setting stiffening ring and changing cross-shaped ribbed plate thickness significantly. In contrast, if the thickness and length of stiffening ring are changed, the impact is insignificant. The results and conclusion can provide reference which is useful to optimize the design of steel spatial tubular joint in such category.

A finite element model on effects of impact load and cavitation on fatigue crack propagation in mechanical bileaflet aortic heart valve

2008 ◽  
Vol 222 (7) ◽  
pp. 1115-1125 ◽  
Author(s):  
H Mohammadi ◽  
R J Klassen ◽  
W-K Wan
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Crack Length ◽  
Heart Valve ◽  
Heart Valves ◽  
Element Model ◽  
Initial Crack ◽  
Initial Crack Length ◽  
Element Approach ◽  
The Impact

Pyrolytic carbon mechanical heart valves (MHVs) are widely used to replace dysfunctional and failed heart valves. As the human heart beats around 40 million times per year, fatigue is the prime mechanism of mechanical failure. In this study, a finite element approach is implemented to develop a model for fatigue analysis of MHVs due to the impact force between the leaflet and the stent and cavitation in the aortic position. A two-step method to predict crack propagation in the leaflets of MHVs has been developed. Stress intensity factors (SIFs) are computed at a small initiated crack located on the leaflet edge (the worst case) using the boundary element method (BEM). Static analysis of the crack is performed to analyse the stress distribution around the front crack zone when the crack is opened; this is followed by a dynamic crack analysis to consider crack propagation using the finite element approach. Two factors are taken into account in the calculation of the SIFs: first, the effect of microjet formation due to cavitation in the vicinity of leaflets, resulting in water hammer pressure; second, the effect of the impact force between the leaflet and the stent of the MHVs, both in the closing phase. The critical initial crack length, the SIFs, the water hammer pressure, and the maximum jet velocity due to cavitation have been calculated. With an initial crack length of 35 μm, the fatigue life of the heart valve is greater than 60 years (i.e. about 2.2×109 cycles) and, with an initial crack length of 170 μm, the fatigue life of the heart valve would be around 2.5 years (i.e. about 9.1×107 cycles). For an initial crack length greater than 170 μm, there is catastrophic failure and fatigue cracking no longer occurs. A finite element model of fatigue analysis using Patran command language (PCL custom code) in MSC software can be used to evaluate the useful lifespan of MHVs. Similar methodologies can be extended to other medical devices under cyclic loads.

scholarly journals Collapse Behaviour of a Concrete-Filled Steel Tubular Column Steel Beam Frame under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lian Song ◽  
Hao Hu ◽  
Jian He ◽  
Xu Chen ◽  
Xi Tu
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Mechanical Performance ◽  
Impact Load ◽  
Frame Structure ◽  
Actual Condition ◽  
Transverse Impact ◽  
Time Curve ◽  
Finite Element Software ◽  
The Impact

The progressive collapse of a concrete-filled steel tubular (CFST) frame structure is studied subjected to impact loading of vehicle by the finite-element software ABAQUS, in the direct simulation method (DS) and alternate path method (AP), respectively. Firstly, a total of 14 reference specimens including 8 hollow steel tubes and 6 CFST specimens were numerically simulated under transverse impact loading for verification of finite-element models, which were compared with the existing test results, confirming the overall similarity between them. Secondly, a finite-element analysis (FEA) model is established to predict the impact behaviour of a five-storey and three-span composite frame which was composed of CFST columns and steel beams under impact vehicle loading. The failure mode, internal force-time curve, displacement-time curve, and mechanical performance of the CFST frame were obtained through analyzing. Finally, it is concluded that the result by the DS method is closer to the actual condition and the collapse process of the structure under impact load can be relatively accurately described; however, the AP method is not.

scholarly journals Nonlinear Pounding Analysis of Multispan and Simply Supported Beam Bridges Subjected to Strong Ground Motions

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hong-Yu Jia ◽  
Xian-Lin Lan ◽  
Nan Luo ◽  
Jian Yang ◽  
Shi-Xiong Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Parameter Analysis ◽  
Cross Sectional ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Finite Element Software ◽  
Impact Element ◽  
Bearing Stiffness ◽  
The Impact ◽  
Gap Width

To investigate the nonlinear impact effect of multispan simply supported beam bridges under strong earthquakes, firstly, the dynamic motion equation, the algorithm of its solution, and some pounding modelling methods are presented and the finite element model of a considered multispan simply supported railway beam bridge is established in the nonlinear finite element software of SAP2000 in which the primary nonlinear characteristics of the bearing and the impact element are considered herein. Secondly, the natural vibration characteristic of the considered railway bridge is analyzed to prepare for the subsequent parameter analysis. Finally, the influence of three nonlinear parameters, i.e., stiffness of impact element, separation gap width of expansion joint, and bearing stiffness, on impact responses of bridge structures is studied. The results show that the first several modes of multispan simply supported beam bridges are mainly longitudinal and vertical vibrations. Under longitudinal seismic excitations, the large longitudinal displacement response is induced possibly and results in the collision or even unseating of superstructures at the expansion joints and abutments. The influence of separation gap width between adjacent decks on the pounding effect of bridges is greater than that of collision stiffness originated from the pounding modelling element. The impact force and pounding number run up to the maximum conditional on the collision stiffness of 9.9 × 109 (N/m) and the separation gap width of 0.14 (m). The bearing stiffness affects significantly the displacement of the pier top and the cross-sectional internal force at the bottom of piers but has little effect on the collision force and number.

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