Behavior of Interface Pressure Distribution in a Single Bolt-Flange Assembly Subjected to Heat Flux

1992 ◽  
Vol 114 (2) ◽  
pp. 231-236 ◽  
Author(s):  
S. Itoh ◽  
Y. Shiina ◽  
Y. Ito
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Pressure Distribution ◽  
Thermal Loading ◽  
Thermal Contact ◽  
Bolted Joint ◽  
Interface Pressure ◽  
Short Period ◽  
Series Of Experiments ◽  
Axial Heat

This paper describes the thermal behavior of a single bolt-flange assembly, emphasizing the correlation between the thermal contact resistance, thermal deformation of joint surroundings and interface pressure distribution, i.e., mechanically-thermally closed loop effect. Through a series of experiments, the major findings are as follows: (1) The thermal behavior of the bolted joint is dependent upon the sinusoidal-like distribution of the interface pressure, for instance, it showing the additional heat flow in radial direction under the axial heat flux. (2) The bolted joint with ordinarily geometric specification is in thermal stability except for a short period after thermal loading.

Effects of Parameters on the Two-Phase Flow Instability in a Microchannel

2018 ◽  
Author(s):  
Yefei Liu ◽  
Yang Liu ◽  
Xingtuan Yang ◽  
Liqiang Pan
Keyword(s):  
Heat Flux ◽  
High Speed ◽  
Flow Instability ◽  
Working Fluid ◽  
Two Phase ◽  
Short Period ◽  
Period Oscillation ◽  
Data Acquisition Card ◽  
Series Of Experiments ◽  
Vertical Microchannel

Series of experiments are conducted in a single microchannel, where subcooled water flows upward inside a transparent and vertical microchannel. The cross section of the channel is rectangle with the hydraulic diameter of 2.8mm and the aspect ratio of 20. The working fluid is 3–15K subcooled and surface heat flux on the channel is between 0–3.64 kW/m2, among which two-phase instability at low vapor quantity may occur. By using a novel transparent heating technique and a high-speed camera, visualization results are obtained. The parameters are acquired with a National Instruments Data Acquisition card. In the experiments, long-period oscillation and short-period oscillation are observed as the primary types of instability in a microchannel. Instability characteristics represented from signals correspond well with the flow pattern. Moreover, effects of several parameters are investigated. The results indicate that the oscillating period generally increases with the heat flux density and decreases with inlet subcooling, while the effects of inlet resistance are more complex.

Interface pressure distributions and thermal contact resistance of a bolted joint

2005 ◽  
Vol 461 (2060) ◽  
pp. 2339-2354 ◽  
Author(s):  
M Tirovic ◽  
G.P Voller
Keyword(s):  
Cast Iron ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Conductive Heat ◽  
Bolted Joint ◽  
Interface Pressure ◽  
Pressure Distributions ◽  
Area Of Interest ◽  
Wide Range

The paper studies interface pressure distributions and thermal contact resistance (TCR) of a large automotive bolted joint. The research was initiated by the need to determine accurately conductive heat dissipation from a commercial vehicle disc brake. The main area of interest was the conduction between the grey cast iron disc and the spheroidal graphite cast iron wheel carrier. The bolt clamp forces and interface pressure distributions were investigated theoretically and experimentally. Finite-element analyses and pressure-sensitive paper experiments provided very similar interface pressure distributions. TCR change with interface pressure was studied experimentally, by conducting numerous temperature measurements. The derived linear relationship is of generic nature, enabling the calculation of the TCR for a variety of engineering bolted joints, over a wide range of interface pressures.

Bolted Joint Interface Pressure for Thermal Contact Resistance

1971 ◽  
Vol 38 (2) ◽  
pp. 542-545 ◽  
Author(s):  
T. L. Bradley ◽  
T. J. Lardner ◽  
B. B. Mikic
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Joint Interface ◽  
Bolted Joint ◽  
Interface Pressure ◽  
Flat Plates ◽  
Pressure Distributions ◽  
Photoelastic Analysis

One of the parameters needed to calculate the thermal contact resistance across a bolted joint is the interface pressure distribution between the plates of the joint [1, 2]. As part of a study [3] on thermal joint conductance, a three-dimensional photoelastic analysis using the stress freezing technique was used to predict the interface pressure. Nine bolted joint geometries were investigated using smooth flat plates of photoelastic material and equal thickness. The resulting interface pressure distributions which are presented are sufficiently accurate for the calculation of thermal contact resistance.

Factors Affecting Contact Pressure Distribution on Bolted Joint Interface

2016 ◽  
Vol 693 ◽  
pp. 126-133
Author(s):  
Jing Ping Liao ◽  
Ding Wen Yu ◽  
Ping Fa Feng
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Radius ◽  
Joint Interface ◽  
Bolted Joint ◽  
Contact Interface ◽  
Interface Pressure ◽  
Contact Pressure Distribution ◽  
Factors Affecting ◽  
Bolt Diameter

To investigate factors affecting contact interface pressure distribution in bolted joint, a parametric model was established by ANSYS APDL language in this paper. The contact pressure distribution on bolted joint interface was obtained through interpolating and revising contact interface forces. It is observed that the position of peak interface pressure is between the edge of bolt hole and the edge of bolt head. The contact pressure linearly changes with the bolt load while the distribution trend and radius remain unchanged. When the total thickness of clamped members is fixed, the contact pressure distribution varies from concentrated to uniform with the increasing member thickness ratio, and the maximum contact radius is reached while the member thickness is equal. When one clamped member thickness is fixed, increasing the other’s thickness can also reduce the contact pressure concentration, but the effect gradually weakens. Increasing bolt diameter can slightly increase the absolute contact radius but decrease the normalized contact radius. The inclusion of a washer under the nut can slightly promote interface clamping.

THERMAL BEHAVIOR AND IGNITION OF HIGH-ENERGY MATERIALS CONTAINING B, ALB2, AND TIB2

2020 ◽  
Author(s):  
A. G. Korotkikh ◽  
◽  
V. A. Arkhipov ◽  
I. V. Sorokin ◽  
E. A. Selikhova ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Flux Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Heat Flux Density ◽  
Ignition Delay Time ◽  
High Energy ◽  
Energy Materials ◽  
High Energy Materials

The paper presents the results of ignition and thermal behavior for samples of high-energy materials (HEM) based on ammonium perchlorate (AP) and ammonium nitrate (AN), active binder and powders of Al, B, AlB2, and TiB2. A CO2 laser with a heat flux density range of 90-200 W/cm2 was used for studies of ignition. The activation energy and characteristics of ignition for the HEM samples were determined. Also, the ignition delay time and the surface temperature of the reaction layer during the heating and ignition for the HEM samples were determined. It was found that the complete replacement of micron-sized aluminum powder by amorphous boron in a HEM sample leads to a considerable decrease in the ignition delay time by a factor of 2.2-2.8 at the same heat flux density due to high chemical activity and the difference in the oxidation mechanisms of boron particles. The use of aluminum diboride in a HEM sample allows one to reduce the ignition delay time of a HEM sample by a factor of 1.7-2.2. The quasi-stationary ignition temperature is the same for the AlB2-based and AlB12-based HEM samples.

scholarly journals A new multifield finite element method in steady state heat analysis

2005 ◽  
Vol 9 (1) ◽  
pp. 111-130 ◽  
Author(s):  
Dubravka Mijuca ◽  
Ana Ziberna ◽  
Bojan Medjo
Keyword(s):  
Finite Element Method ◽  
Heat Flux ◽  
Finite Element ◽  
Thermal Loading ◽  
Mixed Finite Element ◽  
Finite Element Approach ◽  
Benchmark Tests ◽  
Element Approach ◽  
Steady State Heat ◽  
Solid Bodies

A new original primal-mixed finite element approach and related hexahedral finite element HC:T/q for the analysis of behavior of solid bodies under thermal loading is presented. The essential contributions of the present approach is the treatment of temperature and heat flux as fundamental variables that are simultaneously calculated, as well as capability to introduce initial and prescribed temperature and heal flux. In order to minimize accuracy error and enable introductions afflux constraints, the tensorial character of the present finite element equations is fully respected. The proposed finite element is subjected to some standard benchmark tests in order to test convergence of the results, which enlighten the effectiveness and reliability of the approach proposed.

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