Estimation Of Heat Generation Research Articles

3J7b-4 Viscoelasticity Estimation of Soft Tissue for Estimation of Heat Generation in Application of Ultrasonic Surgical Knife(Medical ultrasound)

3J7b-4 Viscoelasticity Estimation of Soft Tissue for Estimation of Heat Generation in Application of Ultrasonic Surgical Knife(Medical ultrasound)

Heat generation and temperature prediction in metal cutting: A review and implications for high speed machining

Determination of the maximum temperature and temperature distribution along the rake face of the cutting tool is of particular importance because of its controlling influence on tool life, as well as, the quality of the machined part. Numerous attempts have been made to approach the problem with different methods including experimental, analytical and numerical analysis. Although considerable research effort has been made on the thermal problem in metal cutting, there is hardly a consensus on the basics principles. The unique tribological contact phenomenon, which occur in metal cutting is highly localized and non-linear, and occurs at high temperatures, high pressures and high strains. This has made it extremely difficult to predict in a precise manner or even assess the performance of various models developed for modelling the machining process. Accurate and repeatable heat and temperature prediction remains challenging due to the complexity of the contact phenomena in the cutting process. In this paper, previous research on heat generation and heat dissipation in the orthogonal machining process is critically reviewed. In addition, temperature measurement techniques applied in metal cutting are briefly reviewed. The emphasis is on the comparability of test results, as well as, the relevance of temperature measurement method to high speed cutting. New temperature measurement results obtained by a thermal imaging camera in high speed cutting of high strength alloys are also presented. Finally, the latest work on estimation of heat generation, heat partition and temperature distribution in metal machining is reviewed. This includes an exploration of the different simplifying assumptions related to the geometry of the process components, material properties, boundary conditions and heat partition. The paper then proposes some modelling requirements for computer simulation of high speed machining processes.

Three-Dimensional Inverse Estimation of Heat Generation in Board Mounted Chips

The conjugate gradient method (CGM) and the general purpose commercial code CFX 4.2-based inverse algorithm are utilized in a three-dimensional inverse heat conduction problem to estimate the strength of heat generation for chips on a printed circuit board (PC-board). The mathematical formulations for simultaneously solving the strength of heat generation for multiple chips are derived. The advantage of calling the CFX 4.2 code as a subroutine in the present inversecalculation lies in that many dife cult but practical three-dimensional inverse problems can be solved under this construction because the general-purpose commercial code has the ability to solve the direct problem easily.Resultsobtained by using theCGM to solvethisthree-dimensional inverseproblem fortwo chipsarejustie ed based on thenumericalexperimentswith thesimulated exactand inexact measurements. It is concluded that accurate heat generation for each chip can be estimated simultaneously by the CGM except for the e nal time. The reason for and improvement of this singularity are addressed.

Some Basic Aspects of Geometrical Characteristics of Pulsed Current Vertical-up GMA Weld.

The performance of pulsed current gas metal arc welding (GMAW) in vertical-up position has been studied in reference to thermal behaviour of the droplet at the time of deposition affecting the geometrical characteristics of weld deposit. A more realistic estimation of heat generation at tip of the filler wire has been worked out by modifying its resistive heating component using effective current (RMS value) of the pulse current wave. The estimated rate of heat generation and measured burnoff rate of the filler wire are correlated to a factor o defined as summarised influence of pulse parameter such as peak current, base current, pulse duration and pulse frequency. Analysis of heat balance in between the heat generated at tip of the filler wire and heat consumed in melting the volume of filler wire fed to the arc indicates that the temperature of droplet decreases with the increase of both o and mean current. The variation in pulse parameters affects the weld geometry by maintaining a good correlation with factor o. In consideration of these correlations, a qualitative understanding over the control of pulse current G MAW process in vertical-up position, affecting weld geometry has been developed.