scholarly journals Examination of thermally induced deformation of a synchrotron radiation mirror using finite element analysis

1989 ◽  
Vol 60 (7) ◽  
pp. 1969-1972 ◽  
Author(s):  
C. Lenardi ◽  
C. Vecile ◽  
R. Vitali ◽  
R. Rosei
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Synchrotron Radiation ◽  
Element Analysis ◽  
Thermally Induced

Finite-element study of a toothed-crystal monochromator

1998 ◽  
Vol 5 (3) ◽  
pp. 667-669 ◽  
Author(s):  
J. Hrdý ◽  
J. Plesˇek
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Synchrotron Radiation ◽  
Radiation Power ◽  
Average Thickness ◽  
Radiation Power Density ◽  
Element Analysis ◽  
Thermally Induced ◽  
Radiation Beams ◽  
Element Study

A toothed-crystal monochromator, proposed in previous papers, is a modification of an inclined monochromator, which reduces the impinging radiation power density on the surface of a crystal for broad synchrotron radiation beams. The surface of the monochromator has a triangular toothed structure oriented in such a way that it represents an inclined monochromator. Finite-element analysis of thermally induced deformation was performed for a particular shape of toothed crystal and for a flat crystal of the same average thickness. It was estimated that the toothed-crystal monochromator may provide 70% higher radiation power than the flat-crystal monochromator.

Investigation of the Lead-On-Chip Package’s Reliability

1998 ◽  
Vol 120 (2) ◽  
pp. 171-174 ◽  
Author(s):  
P.-H. Tsao ◽  
L. C. Chang ◽  
T. C. Chen ◽  
C. Haung ◽  
C. Z. Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Flexural Modulus ◽  
Test Chip ◽  
Element Analysis ◽  
Thermally Induced ◽  
Molding Compounds ◽  
Different Types ◽  
Induced Stresses ◽  
On Chip

An assembly test chip (ATC), consisting of varieties of test structures, had been utilized to monitor the package integrity of SOJ lead-on-chip (LOC) packages after various reliability tests. Two different types of epoxy molding compounds, namely biphenyl and EOCN epoxies, were chosen to investigate their effects on package’s reliability. After the reliability tests, silicon chip crack was observed in three test samples due to the existence of a large chip backside chipping (˜120 μm). Qualitative study about this failure mechanism was carried out by a finite element analysis and it was found that, due to the higher flexural modulus and CTE of the biphenyl epoxy, the thermally induced stresses developed in the chip encapsulated by this epoxy during reliability tests were more likely to cause the crack propagation in the silicon chip than those induced by using EOCN type epoxy.

Determining track-induced lateral thermal expansion forces on a curved railway track

2021 ◽  
pp. 095440972199531
Author(s):  
Jubair A Musazay ◽  
Allan M Zarembski ◽  
Joseph W Palese
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Stress Analysis ◽  
Railway Track ◽  
Thin Wall ◽  
Element Analysis ◽  
Thermally Induced ◽  
Wide Range ◽  
Research Studies

This research studies the development of lateral thermal expansion forces on a curved railway track. The geometric alignment of a railway right of way often requires railway tracks to be curved. This curvature which is usually defined by the radius of curvature or degree of curvature represents a higher level of complexity in the track’s analysis and design process. Particularly, presence of curvature on the track introduces multiple sources of force in the lateral (radial) direction, including, but not limited to, lateral thermal expansion, lateral wheel/rail forces due to centrifugal action, lateral components of vertical loads, bogie hunting and nosing effects of locomotives, and vehicle curving dynamics. Some of these forces are well understood such as centrifugal forces while some are not as well understood, such as lateral thermal expansion forces. To bridge this gap, this research studies the development of track-induced lateral thermal expansion forces on a curved railway track. In this research, the curved track is assumed to be an arbitrary arc section of a circular track and is modeled as an equivalent idealized circular ring for analysis. Owing to its importance, three analytical methods are used to include: 1) Timoshenko thermoelastic stress analysis in cylindrical coordinate system, 2) mechanics of thin wall cylinders and 3) adaptation of a variational calculus formulation method from a previous comparable study. A fourth analysis approach is also introduced using a commercially available finite element analysis package. The results of these analyses are compared through a wide range of parametric studies and are then validated by the finite element analysis. The results of this study showed that the several methods presented in this paper, could be used to approximate thermally induced expansion behavior (pre-buckling) on a curved railway track. While all three techniques are effective, the Timoshenko stress analysis method appears to be the most suitable as it is a direct method that examines the stress build up from the element level and takes into account additional material properties, such as the Poisson effect. The research resulted in a methodology for determining load transfer from thermally induced forces in curved railroad track to the fastener and supporting structure.

Sign in / Sign up

Export Citation Format

Share Document