scholarly journals Investigation into Methods for Predicting Connection Temperatures

10.14311/1099 ◽  
2009 ◽  
Vol 49 (1) ◽  
Author(s):  
K. Anderson ◽  
M. Gillie
Keyword(s):  
Mechanical Response ◽  
Strength Degradation ◽  
Experimental Results ◽  
Material Strength ◽  
Transfer Model ◽  
Temperature Profiles ◽  
Lumped Mass ◽  
Capacitance Method ◽  
In Fire ◽  
Over Time

The mechanical response of connections in fire is largely based on material strength degradation and the interactions between the various components of the connection. In order to predict connection performance in fire, temperature profiles must initially be established in order to evaluate the material strength degradation over time. This paper examines two current methods for predicting connection temperatures: The percentage method, where connection temperatures are calculated as a percentage of the adjacent beam lower-flange, mid-span temperatures; and the lumped capacitance method, based on the lumped mass of the connection. Results from the percentage method do not correlate well with experimental results, whereas the lumped capacitance method shows much better agreement with average connection temperatures. A 3D finite element heat transfer model was also created in Abaqus, and showed good correlation with experimental results. 

The Role of Mechanical Tension in Neurons

2010 ◽  
Vol 1274 ◽  
Author(s):  
Taher Saif ◽  
Jagannathan Rajagopalan ◽  
Alireza Tofangchi
Keyword(s):  
Mechanical Response ◽  
Mechanical Forces ◽  
Active Tension ◽  
Mechanical Tension ◽  
Deformation Response ◽  
Linear Force ◽  
Tension Regulation ◽  
Over Time

AbstractWe used high resolution micromechanical force sensors to study the in vivo mechanical response of embryonic Drosophila neurons. Our experiments show that Drosophila axons have a rest tension of a few nN and respond to mechanical forces in a manner characteristic of viscoelastic solids. In response to fast externally applied stretch they show a linear force-deformation response and when the applied stretch is held constant the force in the axons relaxes to a steady state value over time. More importantly, when the tension in the axons is suddenly reduced by releasing the external force the neurons actively restore the tension, sometimes close to their resting value. Along with the recent findings of Siechen et al (Proc. Natl. Acad. Sci. USA 106, 12611 (2009)) showing a link between mechanical tension and synaptic plasticity, our observation of active tension regulation in neurons suggest an important role for mechanical forces in the functioning of neurons in vivo.

Review of Fire Performance Experiment of Concrete-Filled Steel Tubular Columns

2014 ◽  
Vol 638-640 ◽  
pp. 1397-1401
Author(s):  
Kai Xiang ◽  
Guo Hui Wang ◽  
Yan Chong Pan
Keyword(s):  
Load Ratio ◽  
Experimental Results ◽  
Research Progress ◽  
Future Research ◽  
Fire Performance ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Cross Sectional Dimension ◽  
Cfst Columns ◽  
In Fire

This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

scholarly journals Experimental results on the influence of gas on the mechanical response of peats

Géotechnique ◽  
2019 ◽  
Vol 69 (9) ◽  
pp. 753-766 ◽  
Author(s):  
Cristina Jommi ◽  
Stefano Muraro ◽  
Edoardo Trivellato ◽  
Cor Zwanenburg
Keyword(s):  
Mechanical Response ◽  
Experimental Results

scholarly journals Ageing simulation of a hydraulic engine mount: A data-informed finite element approach

2018 ◽  
Vol 233 (10) ◽  
pp. 2432-2442 ◽  
Author(s):  
Payam Soltani ◽  
Christophe Pinna ◽  
David J Wagg ◽  
Roly Whear
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Element Model ◽  
Experimental Results ◽  
Softening Effect ◽  
Engine Mounts ◽  
Ageing Behaviour ◽  
Ageing Model ◽  
Engine Mount ◽  
Vehicle Suspension System

Hydraulic engine mounts are key elements in an automotive vehicle suspension system that typically experience a change of their designed function during their working lifetime due to progressive material ageing, primarily from the elastomeric component. Ageing of the engine mount, resulting from severe and continuous mechanical and thermal loads, can have a detrimental impact on the ride and comfort and long-term customer satisfaction. This paper introduces a new practical methodology for simulating the ageing behaviour of engine mounts resulting from the change in properties of their elastomeric main spring component. To achieve this, a set of dynamic mechanical thermal analysis tests were conducted on elastomeric coupons taken from a set of engine mounts with different service and ageing conditions. These experimental results were used to characterise the change in mechanical response of the elastomer and to build up an empirical elastomer ageing model. Then a finite element model of the main spring was developed that used the elastomer ageing model so that the ageing behaviour of the engine mount could be simulated. The resulting ageing model was verified by using experimental results from a second batch of ex-service engine mounts. The results show an increasing trend of the vertical static stiffness of the engine mounts with distance travelled (or age) up to a certain distance (approximately 95,000 km). The trend is then reversed and a softening effect is observed. Moreover, the results reveal that both the maximum stiffness value and the distance travelled at the peak stiffness decrease as the temperature increases.

scholarly journals COMPRESSION OF ECAPED TITANIUM MICRO-PILLARS FOR TWO PRINCIPAL ORIENTATIONS

2020 ◽  
Vol 27 ◽  
pp. 1-5
Author(s):  
David Vokoun ◽  
Jan Maňák ◽  
Karel Tesař ◽  
Stanislav Habr
Keyword(s):  
Room Temperature ◽  
Focused Ion Beam ◽  
Mechanical Response ◽  
Thermomechanical Processing ◽  
Ion Beam ◽  
Orientation Dependence ◽  
Material Strength ◽  
Angular Pressing ◽  
Macro Scale ◽  
Micro Pillars

The thermomechanical processing by equal-channel angular pressing (ECAP) is used for certain metals and alloys in order to make their structure fine and to increase material strength. In the previous study done at our institute, grade 2 titanium was successfully processed using four consecutive route A passes via a 90 ° ECAP die with high backpressure at room temperature. Orientation dependence of compressive and tensile loading of ECAPed titanium samples was demonstrated at macro-scale. However, scarce attention has been paid so far to the mechanical behavior of ECAPed titanium samples at micro-scale. In the present study, compression experiments on titanium micropillars, fabricated using focused ion beam, are carried out for two main directions in respect to preceding ECAP pressing (insert and extrusion directions). The purpose of this study is to discuss the orientation dependence of mechanical response during compression of the as-ECAPed titanium micro-pillars.

Heat transfer model for calculation of the temperature field inside thin-walled sections in fire

2021 ◽  
Vol 169 ◽  
pp. 108416
Author(s):  
Michał Malendowski ◽  
Wojciech Szymkuć ◽  
Piotr Turkowski ◽  
Adam Glema ◽  
Wojciech Węgrzyński
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Thin Walled ◽  
In Fire

MNVPCS: Multinode Virtual-Point–Based Charging Scheme to Prolong the Lifetime of Wireless Rechargeable Sensor Networks

2019 ◽  
Vol 63 (2) ◽  
pp. 283-294
Author(s):  
Hong-Yi Chang ◽  
Zih-Huan Hang ◽  
Yih-Jou Tzang
Keyword(s):  
Energy Consumption ◽  
Sensor Networks ◽  
Experimental Results ◽  
Sensor Nodes ◽  
Wireless Charging ◽  
Mobile Wireless ◽  
Wireless Rechargeable Sensor Networks ◽  
Virtual Point ◽  
Over Time

Abstract Wireless-charging technology can utilize a mobile wireless charging vehicle (WCV) to rescue dying nodes by supplementing their remaining energy, and using WCVs in this way forms wireless rechargeable sensor networks (WRSNs). However, a WCV in a WRSN encounters several challenges, collectively called the optimized charging problem. This problem involves a set of sensor nodes randomly distributed on the ground for which the WCV must determine an appropriate travel path to charge the sensor nodes. Because these sensor nodes have different workloads, they exhibit different energy consumption profiles over time. Resolving the above-mentioned problem requires the determination of the priority of charging the sensor nodes based on the order in which they are expected to die and subsequently finding the most efficient path to charge the sensor nodes such that sensor death is avoided for as long as possible. Furthermore, the most efficient placement of the charging point needs to be considered when planning the charging path. To address this, the proposed multinode virtual point-based charging scheme (MNVPCS) considers both the planning of an efficient charging and the best location for the charging point. Experimental results show that MNVPCS can improve the lifetime of the entire WRSN and substantially outperform other methods on this measure.

Sign in / Sign up

Export Citation Format

Share Document