scholarly journals Analysis of metal transfer and weld geometry in hot-wire GTAW with indirect resistive heating

2020 ◽  
Vol 64 (12) ◽  
pp. 2109-2117
Author(s):  
T. Ungethüm ◽  
E. Spaniol ◽  
M. Hertel ◽  
U. Füssel
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Metal Transfer ◽  
Hot Wire ◽  
Melt Pool ◽  
Gtaw Process ◽  
The Wire ◽  
Wire Feeding ◽  
Data Acquisition Unit ◽  
The Impact

Abstract In this publication, the different metal transfer modes of a hot-wire GTAW process with indirect resistive preheating of the wire are presented. The hot-wire GTAW process is characterized by an additional preheating unit that is used to heat the wire before it reaches the melt pool. Thus, to preheat the wire, the contact between the melt pool and the wire is not necessary. In order to examine the metal transfer of the wire, deposition welds are analysed using a high-speed camera with a laser light source as well as a data acquisition unit. The presented results comprise the impact analysis of the GTAW current, the hot-wire current, the wire feeding rate, the wire feeding angle as well as the wire feeding direction. The observed metal transfer modes can be characterized as either a constant melting bridge (cmb) between the wire and the melt pool or a recurring melting bridge (rmb). The analysis also reveals that the influence of the process parameters and thus the metal transfer mode on the bead properties is only marginal.

scholarly journals Influence of the Wire Feeding on the Wetting Process during Laser Brazing of Aluminum Alloys with Aluminum-Based Braze Material

2019 ◽  
Vol 3 (4) ◽  
pp. 83
Author(s):  
Till Leithäuser ◽  
Peer Woizeschke
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Laser Brazing ◽  
Melt Pool ◽  
External Process ◽  
Propagation Effects ◽  
The Wire ◽  
Wire Feeding ◽  
Wetting Process ◽  
Main Effects

The wetting behavior in laser brazing can be designated as inconstant, caused largely by external process discontinuities such as the wire feeding. To reveal periodic melt pool propagation effects that occur during laser brazing of aluminum and for a better understanding of those effects in laser brazing in general, this paper analyzes high-speed recordings of the brazing process with aluminum alloy. It is demonstrated that two main effects of periodic melt pool behavior in different frequency scales occur during the process, related directly to the wire feeding.

Experimental Calibration of ISV Damage Model Constants for Pure Copper for High-Speed Impact Simulation

2016 ◽  
Author(s):  
Yangqing Dou ◽  
Yucheng Liu ◽  
Wilburn Whittington ◽  
Jonathan Miller
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Split Hopkinson Pressure Bar ◽  
Internal State ◽  
Pure Copper ◽  
Damage Model ◽  
Hopkinson Pressure Bar ◽  
Experimental Calibration ◽  
High Speed Impact ◽  
The Impact

Coefficients and constants of a microstructure-based internal state variable (ISV) plasticity damage model for pure copper have been calibrated and used for damage modeling and simulation. Experimental stress-strain curves obtained from Cu samples at different strain rate and temperature levels provide a benchmark for the calibration work. Instron quasi-static tester and split-Hopkinson pressure bar are used to obtain low-to-high strain rates. Calibration process and techniques are described in this paper. The calibrated material model is used for high-speed impact analysis to predict the impact properties of Cu. In the numerical impact scenario, a 100 mm by 100 mm Cu plate with a thickness of 10 mm will be penetrated by a 50 mm-long Ni rod with a diameter of 10mm. The thickness of 10 mm was selected for the Cu plate so that the Ni-Cu penetration through the thickness can be well observed through the simulations and the effects of the ductility of Cu on its plasticity deformation during the penetration can be displayed. Also, that thickness had been used by some researchers when investigating penetration mechanics of other materials. Therefore the penetration resistance of Cu can be compared to that of other metallic materials based on the simulation results obtained from this study. Through this study, the efficiency of this ISV model in simulating high-speed impact process is verified. Functions and roles of each of material constant in that model are also demonstrated.

Free Vibration Analysis for Thin Wire of Modern Wiresaw Between Sliced Wafers in Wafer Manufacturing Processes

2000 ◽  
Author(s):  
Songbin Wei ◽  
Imin Kao
Keyword(s):  
High Speed ◽  
Free Vibration Analysis ◽  
Equation Of Motion ◽  
Manufacturing Processes ◽  
Thin Wire ◽  
Wire Vibration ◽  
The Wire ◽  
The Impact ◽  
Wafer Manufacturing ◽  
Impact Problem

Abstract In wiresaw manufacturing process where thin wire moving at high speed is pushed onto ingot to produce slices of wafer, the wire is constrained by two wafer walls as it slices into the ingot. In this paper, we investigate the vibration of such wire under the constraints of wafer walls. To address this problem, the model for wire vibration with impact to wafer walls is developed. The equation of motion is discretized using the Galerkin’s method. The principle of impulse and momentum is utilized to solve the impact problem. The results of analysis and simulation indicate that the response under a pointwise sinusoidal excitation is neither periodical nor symmetric with respect to the horizontal axis, due to the excitation from the impact. The wire vibration behavior is affected dramatically by the wafer wall constraints.

scholarly journals Experimental and Numerical Impact Analysis of Automotive Bumper Brackets Made of 2D Triaxially Braided CFRP Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3554
Author(s):  
Robert Böhm ◽  
Andreas Hornig ◽  
Tony Weber ◽  
Bernd Grüber ◽  
Maik Gude
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Damage Model ◽  
Drop Tower ◽  
Structural Deformation ◽  
Impact Behavior ◽  
Speed Test ◽  
Damage Models ◽  
The Impact ◽  
Carbon Fiber Epoxy

The impact behavior of carbon fiber epoxy bumper brackets reinforced with 2D biaxial and 2D triaxial braids was experimentally and numerically analyzed. For this purpose, a phenomenological damage model was modified and implemented as a user material in ABAQUS. It was hypothesized that all input parameters could be determined from a suitable high-speed test program. Therefore, novel impact test device was designed, developed and integrated into a drop tower. Drop tower tests with different impactor masses and impact velocities at different bumper bracket configurations were conducted to compare the numerically predicted deformation and damage behavior with experimental evidence. Good correlations between simulations and tests were found, both for the global structural deformation, including fracture, and local damage entities in the impact zone. It was proven that the developed phenomenological damage models can be fully applied for present-day industrial problems.

Investigation of the Impact Analysis of Microscale Thin-Walled Structures Manufactured by High-Speed Machining

2006 ◽  
Vol 326-328 ◽  
pp. 1599-1602
Author(s):  
Bo Sung Shin
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
High Speed ◽  
Impact Analysis ◽  
Thin Wall ◽  
High Speed Machining ◽  
High Speed Cutting ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
The Impact

High-speed machining (HSM) is very useful method as one of the most effective manufacturing processes because it has excellent quality and dimensional accuracy for precision machining. Recently micromachining technologies of various functional materials with very thin walls are needed in the field of electronics, mobile telecommunication and semiconductors. However, HSM is not suitable for microscale thin-walled structures because of the lack of their structure stiffness to resist high-speed cutting force. A microscale thin wall machined by HSM shows the characteristics of the impact behavior because the high-speed cutting force works very shortly on the machined surface. We propose impact analysis model in order to predict the limit thickness of a very thin-wall and investigate its limit thickness of thin-wall manufactured by HSM using finite element method. Also, in order to verify the usefulness of this method, we will compare finite element analyses with experimental results and demonstrate some applications.

scholarly journals Multilevel spatial impact analysis of high-speed rail and station placement: A short-term empirical study of the Taiwan HSR

2020 ◽  
Vol 13 (1) ◽  
pp. 317-341
Author(s):  
Yu-Hsin Tsai ◽  
Jhong-yun Guan ◽  
Yi-hsin Chung
Keyword(s):  
Empirical Study ◽  
Rural Areas ◽  
High Speed ◽  
Impact Analysis ◽  
Local Level ◽  
Influential Factors ◽  
Policy Implications ◽  
High Speed Rail ◽  
Wide Range ◽  
The Impact

Understanding the impact of high-speed rail (HSR) services on spatial distributions of population and employment is important for planning and policy concerning HSR station location as well as a wide range of complementary spatial, transportation, and urban planning initiatives. Previous research, however, has yielded mixed results into the extent of this impact and a number of influential factors rarely have been controlled for during assessment. This study aims to address this gap by controlling for socioeconomic and transportation characteristics in evaluating the spatial impacts of HSR (including station placement) at multiple spatial levels to assess overall impact across metropolitan areas. The Taiwan HSR is used for this empirical study. Research methods include descriptive statistics, multilevel analysis, and multiple regression analysis. Findings conclude that HSR-based towns, on average, may experience growing population and employment, but HSR-based counties are likely to experience relatively less growth of employment in the tertiary sector. HSR stations located in urban or suburban settings may have a more significant spatial impact. This differential in spatial change may be attributed to a high concentration of some subsectors and transportation services in the study area. Policy implications include adopting policies that encourage higher density at the local level, considering rural areas as a last choice for the installation of new HSR stations, and the use of HSR station placement to initiate brownfield urban regeneration in the urban core.

Oblique Impact Analysis of a Golf Ball

2014 ◽  
Vol 566 ◽  
pp. 443-448 ◽  
Author(s):  
Kazuo Arakawa
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
Impact Analysis ◽  
Video Camera ◽  
Oblique Impact ◽  
Golf Ball ◽  
Normal Velocity ◽  
Velocity Change ◽  
High Speed Video Camera ◽  
The Impact

The oblique impact of a golf ball with a rigid steel target was studied using a high-speed video camera. The video images during the impact were employed to measure the compressional displacement of the ball normal to the target and to determine the normal velocity and acceleration of the ball as a function of time. The rotation angle of the ball was also measured to evaluate the angular velocity during the impact. The results showed that the angular velocity increased and then decreased during the impact. To study the velocity change, we introduced an analytical model and suggested that the ball deformation can play an important role to understand the friction effect during the impact.

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