Transient Thermomechanical Simulation of Laser Hammering in Optoelectronic Package Manufacturing

2004 ◽  
Vol 127 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Ben Ting ◽  
Vincent P. Manno
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Laser Energy ◽  
Steady State Solution ◽  
Heat Fluxes ◽  
State Solution ◽  
Asymptotic State ◽  
Element Analysis ◽  
Finite Element Analysis Simulation ◽  
Focus Spot

Laser hammering (LH) is a process used in the manufacturing of butterfly optoelectronic packages to correct laser-to-fiber misalignment that occurs when the semiconductor lasers are welded in place. High-power, precisely positioned pulsed lasers are used in LH to induce deformation of the fiber support housing to, in turn, induce realignment. A thermomechanical modeling study of LH is reported in this paper, which focuses on the degree to which a steady-state model can predict the asymptotic state of a transient response subjected to a periodic laser excitation. A baseline, two-dimensional fiber mounting/ferrule geometry is employed in a finite element analysis simulation case study. Various laser wave forms are applied to focus spot location sizes of 50 and 200μm over a range of applied heat fluxes (10-1000W∕mm2). Effects of laser energy deposition location, as well as the use of multiple lasers, are also studied. The results show that the steady-state solution is in good agreement with the asymptotic transient response for horizontal fiber displacement and fiber temperature. The laser focus spot surface temperature predictions are also found to be in reasonable agreement. However, the vertical fiber displacement tends to be overpredicted by the steady-state solution, sometimes by as much as an order of magnitude. The causes, both physical and computational, of this disagreement are discussed.

Comparison of Steady State and Asymptotic Transient Thermal-Mechanical Simulations of Optoelectronic Laser Processing

2003 ◽  
Author(s):  
Ben Ting ◽  
Vincent P. Manno
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Laser Energy ◽  
Steady State Solution ◽  
Heat Fluxes ◽  
State Solution ◽  
Final State ◽  
Element Analysis ◽  
Order Of Magnitude ◽  
Focus Spot

Traditional optoelectronic manufacturing of butterfly packages involves laser welding of a fiber mount followed by a tedious realignment procedure to reverse thermally induced distortions commonly referred to as Post Weld Shift (PWS). An alternative PWS compensation technique, Laser Hammering, entails manipulation of the fiber to light alignment through deformation of the fiber housing with high precision laser beams. The goal of this study is to predict and understand fiber displacements for butterfly packages subjected to the laser hammering process using finite element analysis. A standardized, two-dimensional fiber mounting/ferrule geometry is employed in a simulation case study. Various laser waveforms are applied to focus spot diameters of 50 and 200 μm over a range of applied heat fluxes (10 to 1000 W/mm2). The primary investigation focused on the degree to which a steady state (SS) model can predict the final state of a transient response (asymptotic steady state) subjected to a periodic laser excitation. Effects of laser energy deposition location and resolution, as well as the use of multiple lasers were also studied. The results obtained to date show that the steady state solution is in good agreement with the asymptotic transient response (ATR) for the center horizontal fiber displacement and the center fiber temperature. The focus spot region surface temperature predictions of steady state and asymptotic transient simulations were also found to be in reasonable agreement. However, the vertical fiber displacement tends to be over predicted by the steady state solution, sometimes by as much as an order of magnitude. The causes, both physical and computational, of this disagreement are discussed in the paper.

The Timoshenko Beam on an Elastic Foundation and Subject to a Moving Step Load, Part 2: Transient Response

1996 ◽  
Vol 118 (3) ◽  
pp. 285-291 ◽  
Author(s):  
S. F. Felszeghy
Keyword(s):  
Steady State ◽  
Boundary Conditions ◽  
Elastic Foundation ◽  
Transient Response ◽  
Timoshenko Beam ◽  
Equations Of Motion ◽  
Steady State Solution ◽  
State Solution ◽  
Critical Speeds ◽  
Particular Solution

The transient response of a simply supported semi-infinite Timoshenko beam on an elastic foundation to a moving step load is determined. The response is found from summing the solutions to two mutually complementary sets of governing equations. The first solution is a particular solution to the forced equations of motion. The second solution is a solution to a set of homogeneous equations of motion and nonhomogeneous boundary conditions so formulated as to satisfy the initial and boundary conditions of the actual problem when the two solutions are summed. As a particular solution, the steady-state solution is used which is the motion that would appear stationary to an observer traveling with the load. Steady-state solutions were developed in Part 1 of this article for all load speeds greater than zero. The solution to the homogeneous equations of motion is developed here in Part 2. It is shown that the latter solution can be obtained by numerical integration using the method of characteristics. Particular attention is given to the cases when the load travels at the critical speeds consisting of the minimum phase velocity of propagating harmonic waves and the sonic speeds. It is shown that the solution to the homogeneous equations combines with the steady-state solution in such a manner that the beam displacements are continuous and bounded for all finite times at all load speeds including the critical speeds. Numerical results are presented for the critical load speed cases.

Response of a Submerged Cylindrical Shell to an Axially Propagating Step Wave

1965 ◽  
Vol 32 (4) ◽  
pp. 788-792 ◽  
Author(s):  
M. J. Forrestal ◽  
G. Herrmann
Keyword(s):  
Cylindrical Shell ◽  
Steady State ◽  
Wave Front ◽  
Transverse Shear ◽  
Shell Theory ◽  
Steady State Solution ◽  
State Solution ◽  
Rotatory Inertia ◽  
Shear Deformations ◽  
Axial Coordinate

An infinitely long, circular, cylindrical shell is submerged in an acoustic medium and subjected to a plane, axially propagating step wave. The fluid-shell interaction is approximated by neglecting fluid motions in the axial direction, thereby assuming that cylindrical waves radiate away from the shell independently of the axial coordinate. Rotatory inertia and transverse shear deformations are included in the shell equations of motion, and a steady-state solution is obtained by combining the independent variables, time and the axial coordinate, through a transformation that measures the shell response from the advancing wave front. Results from the steady-state solution for the case of steel shells submerged in water are presented using both the Timoshenko-type shell theory and the bending shell theory. It is shown that previous solutions, which assumed plane waves radiated away from the vibrating shell, overestimated the dumping effect of the fluid, and that the inclusion of transverse shear deformations and rotatory inertia have an effect on the response ahead of the wave front.

scholarly journals Comparison of Solvers Performance for Load Flow Analysis

2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Vishnu Sidaarth Suresh
Keyword(s):  
Steady State ◽  
Power System ◽  
Reactive Power ◽  
Flow Analysis ◽  
Steady State Solution ◽  
Load Flow ◽  
State Solution ◽  
Computational Time ◽  
Load Flow Analysis ◽  
Active And Reactive Power

Load flow studies are carried out in order to find a steady state solution of a power system network. It is done to continuously monitor the system and decide upon future expansion of the system. The parameters of the system monitored are voltage magnitude, voltage angle, active and reactive power. This paper presents techniques used in order to obtain such parameters for a standard IEEE – 30 bus and IEEE-57 bus network and makes a comparison into the differences with regard to computational time and effectiveness of each solver

Steady-state solution of traffic flow on a simple road network

2021 ◽  
Vol 33 (5) ◽  
pp. 950-957
Author(s):  
Yu-pei Lyu ◽  
Ming-min Guo ◽  
Peng Zhang ◽  
Rui Fang ◽  
Zhi-yang Lin ◽  
...  
Keyword(s):  
Steady State ◽  
Traffic Flow ◽  
Road Network ◽  
Steady State Solution ◽  
State Solution
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