A Numerical Approach for the Hygro-Thermal Monitoring of Timber Structures under Environmental Conditions

2013 ◽  
Vol 778 ◽  
pp. 786-793
Author(s):  
Alessandra Genoese ◽  
Andrea Genoese ◽  
Stefania Fortino ◽  
Petr Hradil
Keyword(s):  
Numerical Approach ◽  
Coupled Analysis ◽  
Timber Structures ◽  
Climate Variations ◽  
Thermal Monitoring ◽  
Climate Fluctuations ◽  
User Subroutine ◽  
Natural Climate ◽  
Numerical Case Study

The monitoring of timber structures exposed to natural climate fluctuations during their service life is an important topic for both their serviceability and safety. Numerical methods based on the recent advances in hygro-thermal modelling of wood can integrate the usual sensor-based monitoring techniques by reducing the maintenance costs for timber structures. In this paper, a 3D full coupled analysis based on the multi-Fickian theory with sorption hysteresis of wood is implemented in Abaqus FEM code by defining a new finite element in a user subroutine. To verify the method, the hygro-thermal behaviour of a glulam beam tested in laboratory under variable humidity within a previous research is analysed and the numerical values of moisture content are found to be in agreement with the experimental data. Furthermore, a numerical case-study of a glulam cross section under real climate variations is presented and the related results show the capability of the method to predict the moisture states in each points of the glulam member under continuously variable humidity and temperature.

Milling Curves Influence in Ring Rolling Processes

2014 ◽  
Vol 622-623 ◽  
pp. 956-963 ◽  
Author(s):  
Luca Giorleo ◽  
Elisabetta Ceretti ◽  
Claudio Giardini
Keyword(s):  
Numerical Approach ◽  
The Other ◽  
Ring Rolling ◽  
Roll Speed ◽  
Forming Process ◽  
Industrial Case Study ◽  
Industrial Environment ◽  
Ring Shape ◽  
Deformation Processes

Ring Rolling is a complex hot forming process used for the production of shaped rings, seamless and axis symmetrical workpieces. The main advantage of workpieces produced by ring rolling, compared to other technological processes, is given by the size and orientation of grains, especially on the worked surface which give to the final product excellent mechanical properties. In this process different rolls (Idle, Axial, Guide and Driver) are involved in generating the desired ring shape. Since each roll is characterized by a speed law that can be set independently by the speed law imposed to the other rolls, an optimization is more critical compared with other deformation processes. Usually, in industrial environment, a milling curve is introduced in order to correlate the Idle and Axial roll displacement, however it must be underlined that different milling curves lead to different loads and energy for ring realization. In this work an industrial case study was modeled by a numerical approach: different milling curves characterized by different Idle and Axial roll speed laws (linearly decreasing, constant, linearly increasing) were designed and simulated. The results were compared in order to identify the best milling curve that guarantees a good quality ring (higher diameter, lower fishtail) with lower loads and energy required for manufacturing.

scholarly journals Optimal Design Strategy of a Solar Reflector Combining Photovoltaic Panels to Improve Electricity Output: A Case Study in Calgary, Canada

2021 ◽  
Vol 13 (11) ◽  
pp. 6115
Author(s):  
Moon Keun Kim ◽  
Khalid Osman Abdulkadir ◽  
Jiying Liu ◽  
Joon-Ho Choi ◽  
Huiqing Wen
Keyword(s):  
Solar Radiation ◽  
Electricity Generation ◽  
Low Cost ◽  
Design Strategy ◽  
Numerical Approach ◽  
Optimal Shape ◽  
Energy Technology ◽  
Experimental Database ◽  
Pv Panel

This study explores the combination of photovoltaic (PV) panels with a reflector mounted on a building to improve electricity generation. Globally, PV panels have been widely used as a renewable energy technology. In order to obtain more solar irradiance and improve electricity output, this study presents an advanced strategy of a reflector combining PV panels mounted on a building in Calgary, Canada. Based on an experimental database of solar irradiances, the simulation presents an optimal shape designed and tilt angles of the reflector and consequently improves solar radiation gain and electricity outputs. Polished aluminum is selected as the reflector material, and the shape and angle are designed to minimize the interruption of direct solar radiation. The numerical approach demonstrates the improvement in performance using a PV panel tilted at 30°, 45°, 60°, and 75° and a reflector, tilted at 15.5° or allowed to be tilted flexibly. A reflector tilted at 15.5° can improve solar radiation gains, of the panel, by nearly 5.5–9.2% at lower tilt angles and 14.1–21.1% at higher tilt angles. Furthermore, the flexibly adjusted reflector can improve solar radiation gains on the PV panel, by nearly 12–15.6% at lower tilt angles and 20–26.5% at higher tilt angles. A reflector tilted at 15.5° improves the panel’s output electricity on average by 4–8% with the PV panel tilted at 30° and 45° respectively and 12–19 % with the PV panel tilted at 60° and 75°, annually. Moreover, a reflector that can be flexibly tilted improves electricity output on average by 9–12% with the PV panel tilted at 30° and 45° and 17–23% with the PV panel tilted at 60° and 75°. Therefore, the utilization of a reflector improves the performance of the PV panel while incurring a relatively low cost.

Evaluating the Coupledness of the Aerodynamics and Hydrodynamics on the Estimation of Fatigue Damage Equivalent Load for a Floating Offshore Wind Platform

2018 ◽  
Author(s):  
Samuel Kanner ◽  
Bingbin Yu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Environmental Conditions ◽  
Offshore Wind ◽  
Coupled Analysis ◽  
Offshore Wind Turbine ◽  
Wave Conditions ◽  
Equivalent Load ◽  
The Waves

In this research, the estimation of the fatigue life of a semi-submersible floating offshore wind platform is considered. In order to accurately estimate the fatigue life of a platform, coupled aerodynamic-hydrodynamic simulations are performed to obtain dynamic stress values. The simulations are performed at a multitude of representative environmental states, or “bins,” which can mimic the conditions the structure may endure at a given site, per ABS Floating Offshore Wind Turbine Installation guidelines. To accurately represent the variety of wind and wave conditions, the number of environmental states can be of the order of 103. Unlike other offshore structures, both the wind and wave conditions must be accounted for, which are generally considered independent parameters, drastically increasing the number of states. The stress timeseries from these simulations can be used to estimate the damage at a particular location on the structure by using commonly accepted methods, such as the rainflow counting algorithm. The damage due to either the winds or the waves can be estimated by using a frequency decomposition of the stress timeseries. In this paper, a similar decoupled approach is used to attempt to recover the damages induced from these coupled simulations. Although it is well-known that a coupled, aero-hydro analysis is necessary in order to accurately simulate the nonlinear rigid-body motions of the platform, it is less clear if the same statement could be made about the fatigue properties of the platform. In one approach, the fatigue damage equivalent load is calculated independently from both scatter diagrams of the waves and a rose diagram of the wind. De-coupled simulations are performed to estimate the response at an all-encompassing range of environmental conditions. A database of responses based on these environmental conditions is constructed. The likelihood of occurrence at a case-study site is used to compare the damage equivalent from the coupled simulations. The OC5 platform in the Borssele wind farm zone is used as a case-study and the damage equivalent load from the de-coupled methods are compared to those from the coupled analysis in order to assess these methodologies.

scholarly journals A time-of-use based electricity price package mechanism in retail market considering consumers’ diversity

2020 ◽  
Vol 182 ◽  
pp. 02009
Author(s):  
Gang Luo ◽  
Yujun He ◽  
Chen Zhao ◽  
Xuan Zhang ◽  
Shaohua Lin ◽  
...  
Keyword(s):  
Energy Demand ◽  
Electricity Price ◽  
Demand Elasticity ◽  
Energy Price ◽  
Retail Market ◽  
Specific Time ◽  
Optimal Price ◽  
Numerical Case Study

In the deregulated retail market, consumers should have more right of choice for paying for their energy demand. This paper focuses on the design of electricity price package mechanism in retail market considering the demand elasticity of consumers. An optimal price package mechanism is proposed to incentivize consumers for peak-clipping/valley-filling. Consumers are able to choose the appropriate one from a set of price packages, each of which consists of specific time-of-use energy price and maximum-demand price. A numerical case study has shown the usefulness and effectiveness of the proposed mechanism.

scholarly journals Spectral analysis of multiple cracked beam subjected to moving load

2014 ◽  
Vol 36 (4) ◽  
pp. 245-254
Author(s):  
N. T. Khiem ◽  
P. T. Hang
Keyword(s):  
Dynamic Response ◽  
Moving Load ◽  
Time History ◽  
Theoretical Development ◽  
Multiple Cracks ◽  
Spectral Approach ◽  
Cracked Beam ◽  
Time History Response ◽  
Numerical Case Study

In present paper, the spectral approach is proposed for analysis of multiple cracked beam subjected to general moving load that allows us to obtain explicitly dynamic response of the beam in frequency domain. The obtained frequency response is straightforward to calculate time history response by using the FFT algorithm and provides a novel tool to investigate effect of position and depth of multiple cracks on the dynamic response. The analysis is important to develop the spectral method for identification of multiple cracked beam by using its response to moving load. The theoretical development is illustrated and validated by numerical case study.

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