Simulation of the Thermal Effects on Engineered Polymer Composite Ties

2019 ◽  
Author(s):  
Yin Gao ◽  
Mike McHenry
Keyword(s):  
Polymer Composite ◽  
Thermal Effects ◽  
Field Testing ◽  
Support Condition ◽  
Direct Sunlight ◽  
Temperature Changes ◽  
Service Testing ◽  
Bending Effect ◽  
Thermal Bending ◽  
Potential Alternative

Engineered polymer composite (EPC) ties offer a potential alternative to solid sawn timber ties. These materials are especially attractive for use in regions where wood is susceptible to degradation by moisture and decay organisms. However, recent research at the Transportation Technology Center’s (TTC) Facility for Accelerated Service Testing (FAST) in Pueblo, CO, found that track supported by EPC ties experienced more gage widening variation due to temperature changes than track supported by wood ties. Specifically, the track gage was about 0.2-in. wider in the afternoon than that in the morning on the EPC tie tracks. It is believed that the direct sunlight in the afternoon makes the top surface of the tie expand more than the other parts of the tie, thereby causing the EPC ties to bend and widen track gage. Another observation related to the EPC thermal bending effect is changes to the ballast support condition. When temperatures are cooler, EPC ties tend to experience a center-bound ballast support condition, therefore generating more bending stress on the ties. This paper presents results from computer simulations of the thermal behavior of EPC ties. Future study will focus on field testing to further understand the thermal effects in support of recommendations on the use of EPC ties.

scholarly journals Effect of Drying Temprature on some Properties of Polymer Composite with Epoxy K-153 Matrix

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Nguyen Trung Thanh
Keyword(s):  
Epoxy Resin ◽  
Surface Structure ◽  
Thermal Oxidation ◽  
Oxidation Resistance ◽  
Polymer Composite ◽  
Polymer Composite Material ◽  
Drying Temperature ◽  
Temperature Changes ◽  
Resistance Surface ◽  
Structure Morphology

The article introduces the effects of drying temperature on curing level, thermal endurance, thermal oxidation resistance, surface structure morphology of polymer composite material based on K-153 epoxy resin (K-153 epoxy resin is made from ED-20 epoxy resin modified by thiokol and oligomer acrylate), T-13 glass fiber and hardener polyethylenepolyamine. The results show that the thermal endurance, thermal oxidation resistance, surface structure morphology of polymer composite change much when the drying temperature changes. When the drying temperature increases from 60°C to about 80°C, the structure of the polymer composites are tighter, the thermal endurance, thermal oxidation resistance also increases, however, if the drying temperature is continued to increase, these properties of the material will reduce.

Data-driven analysis on thermal effects and temperature changes of lithium-ion battery

2021 ◽  
Vol 482 ◽  
pp. 228983
Author(s):  
Shan Zhu ◽  
Chunnian He ◽  
Naiqin Zhao ◽  
Junwei Sha
Keyword(s):  
Lithium Ion Battery ◽  
Thermal Effects ◽  
Lithium Ion ◽  
Data Driven ◽  
Temperature Changes

Adaptation as a Mechanism for Gain Control in an Insect Thermoreceptor

2008 ◽  
Vol 100 (4) ◽  
pp. 2137-2144 ◽  
Author(s):  
Harald Tichy ◽  
Harald Fischer ◽  
Ewald Gingl
Keyword(s):  
Temperature Change ◽  
Thermal Effects ◽  
Gain Control ◽  
Input Function ◽  
High Gain ◽  
Oscillation Period ◽  
Rate Of Change ◽  
Temperature Changes ◽  
Precise Information ◽  
Instantaneous Temperature

Adaptation controls the gain of the input-function of the cockroach's cold cell during slowly oscillating changes in temperature. When the oscillation period is long, the cold cell improves its gain for the rate of temperature change at the expense of its ability to code instantaneous temperature. When the oscillation period is brief, however, the cold cell reduces this gain and improves its sensitivity for instantaneous temperature. This type of gain control has an important function. When the cockroach ventures from under cover and into moving air, the cold cell is confronted constantly with brief changes in temperature. To be of any use, a limit in the gain for the rate of change seems to be essential. Without such a limit, the cold cell will always indicate temperature change. The decrease in gain for the rate of change involves an increase in gain for instantaneous temperature. Therefore the animal receives precise information about the temperature at which the change occurs and can seek an area of different temperature. If the cockroach ventures back under cover, the rate of change will become slow. In this situation, a high gain improves the ability to signal slow temperature changes. The cockroach receives the early warning of slow fluctuations or even creeping changes in temperature. A comparison of the cold cell's responses with the temperature measured inside of small, cylindrical model objects indicates that coding characteristic rather than passive thermal effects of the structures enclosing the cold cell are responsible for the observed behavior.

Thermal Buckling of Initially Stressed Thick Plates

1982 ◽  
Vol 104 (3) ◽  
pp. 557-564 ◽  
Author(s):  
Lien-Wen Chen ◽  
E. J. Brunelle ◽  
L. Y. Chen
Keyword(s):  
Initial Stress ◽  
Thermal Effects ◽  
Thick Plate ◽  
Equations Of Motion ◽  
Transversely Isotropic ◽  
Thermal Buckling ◽  
Bending Stress ◽  
Buckling Loads ◽  
Thermal Bending ◽  
Plate Equations

Equations of motion for a transversely isotropic thick plate with thermal effects in a general state of nonuniform initial stress where the effects of transverse shear and rotary inertia are included are derived. The method is to perturb the nonlinear equations of elasticity by an incremental deformation. The resulting equations are linearized and integrated through the thickness of the plate to obtain the thermal elastic plate equations. A reduced set of equations for a thick plate with thermal effects is also given. Finally, the thermal buckling problems are solved for a simply supported rectangular plate in a state of uniform compressive (or tensile) initial stress plus initial bending stress combined with uniform thermal compressive stress plus thermal bending stress. The effects of various parameters on thermal buckling loads are studied.

Thermal Effects while Fatigue Cracking Growth under Bending

2013 ◽  
Vol 592-593 ◽  
pp. 700-703
Author(s):  
Dariusz Rozumek ◽  
Norbert Szmolke
Keyword(s):  
Crack Growth ◽  
Thermal Effects ◽  
Fatigue Cracking ◽  
Fatigue Tests ◽  
Temperature Gradients ◽  
Growth Path ◽  
Temperature Changes ◽  
Crack Growth Path ◽  
Molecular Friction

The paper presents the results of fatigue tests where temperature changes on specimen surfaces were registered. Some different materials were tested. A relation between the crack growth and temperature changes in the propagation place was found. The highest temperature gradients were measured on the crack growth path, and it was caused by molecular friction.

scholarly journals Dynamic Characteristics of an Elastic Structure with Thermal Effects

2020 ◽  
Vol 25 (2) ◽  
pp. 200-208
Author(s):  
Guanhua Xu ◽  
Jianzhong Fu ◽  
Wen He ◽  
Yuetong Xu ◽  
Zhiwei Lin ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Thermal Effects ◽  
Natural Frequencies ◽  
Elastic Structure ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Environmental Testing ◽  
Temperature Changes ◽  
Property Changes

The vibration table in a combination environmental testing device suffers from temperature changes, which cause the dynamic characteristics of the vibration structure to vary. The mechanism of the thermal effect on the dynamic characteristics of an elastic structure is presented, and a modal analysis with thermal effects based on the finite-element method (FEM) is carried out. The results show that the natural frequencies for each order decrease as the temperature increases, while the mode shapes of the vibrator do not change with temperature. Although thermal stress may affect natural frequencies due to the additional initial stress element stiffness, this stress can be neglected in the modal analysis because it is negligible relative to the effect of the material property changes with temperature.

scholarly journals Prototipe Penggerak Atap Kanopi Otomatis Menggunakan Sensor Cahaya, Sensor Hujan Dan Sensor Suhu Berbasis Mikrokontroler ATMega16

2019 ◽  
Vol 6 (1) ◽  
pp. 105
Author(s):  
I Made Adi Wijaya ◽  
I Gusti Agung Putu Raka Agung ◽  
Pratolo Rahardjo
Keyword(s):  
Temperature Sensor ◽  
Circuit Simulation ◽  
Direct Sunlight ◽  
Temperature Changes ◽  
Light Sensor ◽  
Small House ◽  
Higher Temperature ◽  
House Design ◽  
Air Circulation ◽  
Prototype Design

Small house design, sometimes ignoring comfort factors such as air circulation and direct sunlight that can make humidity increase and higher temperature inside the house. Giving a controll system at the part of the house can make the air circulation better. In this paper, the prototype design of automatic roof canopy drive using a light sensor, rain sensor, and an ATMega16 microcontroller based temperature sensor is used to solve the problem. This prototype uses the programming language in BASCOM AVR software and PROTEUS software for circuit simulation. Light sensor in the form of LDR will detect changes in light intensity, that is when dark produces a voltage of 1.17V and logic 0 and when light produces a voltage of 4.30V and logic 1. Rain sensor is used to detect the presence of water in the event of rain, that is in conditions the rain produces a 1.83V voltage and logic 0, whereas in the absence of rain it produces a voltage of 4.70V and logic 1. The LM35 temperature sensor is used to detect temperature changes that occur, namely when temperatures less than 29ºC will logic 0 and when the temperature is over from 29ºC will logic 1. All conditions generated by the three sensors will be converted through the ADC so that it can provide logic input to the microcontroller to drive the servo motor to close or open the canopy roof.

scholarly journals The thermal effects of pulsed ultrasound

1981 ◽  
Vol 37 (1) ◽  
pp. 10-12 ◽  
Author(s):  
V. Sandler ◽  
P. Feingold
Keyword(s):  
Heat Production ◽  
Thermal Effects ◽  
Continuous Beam ◽  
Pulsed Ultrasound ◽  
Temperature Changes ◽  
Pulse Ratio

Heat production by pulsed ultrasound was investigated. Four thermocouples were inserted into the thighs of each of six rabbits at specified depths. Temperature changes were recorded during insonation at different frequencies, intensities and duration of insonation. Significant thermal effects were recorded at both pulse ratios. These temperature increases were greater using a pulse ratio of 1:1 than a pulse ratio of 1:4, but less than those produced by a continuous beam.

An Analytical Model for a Clamped Isotropic Beam Under Thermal Effects

2002 ◽  
Author(s):  
Rodrigo F. A. Marques ◽  
Daniel J. Inman
Keyword(s):  
Boundary Conditions ◽  
Analytical Model ◽  
Thermal Effects ◽  
Natural Frequencies ◽  
Dynamical Behavior ◽  
Beam Theory ◽  
Optimization Procedure ◽  
Temperature Changes ◽  
Thermally Expand ◽  
Spring Constants

Structures and industrial equipment often operate in environments where temperature variations take place. Although thermal effects may be negligible in some cases, they have caused the unexpected failure of mechanical systems many times. Whether or not temperature has significant effects on the dynamical behavior of such machines and structures depends upon several aspects, amongst which are geometry, material properties and boundary conditions. In this paper we investigate the dynamical behavior of a clamped beam under the influence of a uniform, quasi-statically varying temperature field. An analytical model was used, based on Euler-Bernoulli’s beam theory with the introduction of the proper boundary conditions. Temperature effects are included in terms of an axial force that shows up when the beam tends to thermally expand, but this expansion is restrained by the clamping. Preliminary results do not agree with experimental data, since perfect clamping is difficult to achieve in practice. Finally the model is updated with the inclusion of axial and torsional springs connecting the beam to the support. The spring constants were calculated through optimization procedure to minimize the differences between the natural frequencies obtained from the analytical model and the corresponding experimental ones. Agreement with experimental results is reasonable up to the 4th mode of the beam. In the future, this analytical model is to be used for design and simulation of an active controller that accounts for temperature changes in the structure.

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