scholarly journals Wind Load Reduction in Hollow Panel Arrayed Set

2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Michalina Markousi ◽  
Dimitrios K. Fytanidis ◽  
Johannes V. Soulis
Keyword(s):  
Research Work ◽  
Flow Analysis ◽  
Flow Region ◽  
Maximum Load ◽  
Wind Load ◽  
Wind Loading ◽  
Load Reduction ◽  
Low Velocity ◽  
Approach Angle ◽  
Surface Areas

Reducing the wind loading of photovoltaic structures is crucial for their structural stability. In this study, two solar panel arrayed sets were numerically tested for load reduction purposes. All panel surface areas of the arrayed set are exposed to the wind similarly. The first set was comprised of conventional panels. The second one was fitted with square holes located right at the gravity center of each panel. Wind flow analysis on standalone arrayed set of panels at fixed inclination was carried out to calculate the wind loads at various flow velocities and directions. The panels which included holes reduced the velocity in the downwind flow region and extended the low velocity flow region when compared to the nonhole panels. The loading reduction, in the arrayed set of panels with holes ranged from 0.8% to 12.53%. The maximum load reduction occurred at 6.0 m/s upwind velocity and 120.0° approach angle. At 30.00 approach angle, wind load increased but marginally. Current research work findings suggest that the panel holes greatly affect the flow pattern and subsequently the wind load reduction. The computational analysis indicates that it is possible to considerably reduce the wind loading using panels with holes.

scholarly journals The Effects Of Pruning Type On Wind Loading Of Acer Rubrum

2006 ◽  
Vol 32 (1) ◽  
pp. 33-40
Author(s):  
E. Thomas Smiley ◽  
Brian Kane
Keyword(s):  
Center Of Pressure ◽  
Acer Rubrum ◽  
Bending Moment ◽  
Wind Load ◽  
Wind Loading ◽  
Load Reduction ◽  
Before And After

The wind load, bending moment, height, and weight were determined for 81 red maples (Acer rubrum) before and after pruning. Trees were thinned, reduced, lion tailed, or stripped of foliage. All three pruning treatments reduced wind load significantly compared to unpruned trees at all tested velocities (11, 16, and 20 m/sec [25, 35, and 45 mph]). Reduction in wind load increased with increasing velocity. Differences in wind-load reduction between reduction pruning and thinning were not significant at any velocity. The reduction in wind load was linearly related to the amount of weight removed by pruning treatments. Compared to the same trees prior to pruning, the center of pressure height was significantly lowered on thinned and reduced trees, while the center of pressure height did not change on lion-tailed trees.

scholarly journals Effect of the Reinforcement Phase on Indentation Resistance and Damage Characterization of Glass/Epoxy Laminates Using Acoustic Emission Monitoring

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
C. Suresh Kumar ◽  
K. Saravanakumar ◽  
P. Prathap ◽  
M. Prince ◽  
G. Bharathiraja ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Glass Fiber ◽  
Research Work ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Cumulative Energy ◽  
Static Indentation ◽  
Felicity Ratio ◽  
Woven Glass Fiber ◽  
Energy Absorbing

The effect of reinforcement phases on indentation resistance and damage behavior of glass/epoxy laminates was investigated in this research work. Woven glass fiber mat and nonwoven chopped glass fiber mat were used as fiber reinforcement phases for fabricating the laminates. Low-velocity impact and quasi-static indentation tests were performed on both laminates to investigate the contact behavior and energy-absorbing capability. Moreover, the acoustic emission (AE) technique was employed to monitor the indentation damage resistance. AE parameters including normalized cumulative counts (NCC), normalized cumulative energy (NCE), rise angle (RA), and felicity ratio (FR) were analyzed. The bidirectional laminates showed premature load drops and drastic changes in the normalized cumulative counts/energy profile in the beginning of loading cycles, indicating the development of macrodamage such as debonding/delamination. AE sentry function results of bidirectional laminates show longer PII function at the earlier stages, associated with minor PIII function and greater PIV function, indicating the continuous degradation and progression of damage. In contrast, the chopped laminates exhibited superior postimpact performance than the bidirectional laminates. The presence of randomly oriented fibres prevents the delamination crack propagation during compression loading, which was attributed with the increased residual compressive strength.

scholarly journals Analysis on the influence of sinusoidal wind on the structure of pumping unit based on dynamics of solid-fluid interaction

2021 ◽  
Vol 69 (5) ◽  
pp. 165
Author(s):  
Zheng Liang ◽  
Luo-ming Zhao ◽  
Li-qin Tan
Keyword(s):  
Wind Speed ◽  
Wind Field ◽  
Research Work ◽  
Scientific Basis ◽  
Wind Load ◽  
Load Range ◽  
Pumping Unit ◽  
Stress And Deformation ◽  
Fluid Interaction ◽  
Field Area

China National Petroleum Corporation Dingbian oilfield is located in the wind field area of the beam pumping unit affected by the wind load, occurred several pumping unit bracket bending, beam fracturing, horsehead off and horsehead drop and other serious accidents, endanger the equipment and personnel safety. However, there is little research on the influence of beam pumping unit under wind load. Based on the dynamics of solid-fluid interaction theory and the standard k- turbulence model, this paper calculated the polished rod load range of the pumping unit according to the actual working condition of Dingbian oilfield, and established the CYJ10-4.2-53 numerical model of wind field. Under the sinusoidal variable wind speed conditions, the stress and deformation of the beam loader with different sizes of wind load on the beam loader were compared to those of the different sorts. The stress and deformation of the two different types of pumping unit were compared under the wind load. The results show that under the influence of wind load, the rig of the pumping unit bracket has a serious bending deformation, and the safety risk of the front end of the horsehead along the wind load is deformed. When the wind speed reaches 24.48m/s, the horsehead and barcket’s offset is the largest to the top dead point by the wind load, The minimum impact is affected by the wind load at the bottom dead center, The maximum offset of the horsehead and the bracket reached 8.5 mm and 2.16 mm. The research work of this paper provides a scientific basis for the improvement of safety structure for pumping unit in the wind field area.

Wind load reduction effects on inner buildings by exterior porous façades

2020 ◽  
Vol 183 ◽  
pp. 107148
Author(s):  
Yuan-Lung Lo ◽  
Yu-Ting Wu ◽  
Chung-Lin Fu ◽  
Ying-Chang Yu
Keyword(s):  
Wind Load ◽  
Load Reduction

scholarly journals Mechanical Behavior of Entangled Metallic Wire Materials under Quasi-Static and Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3392 ◽  
Author(s):  
Yiwan Wu ◽  
Lei Jiang ◽  
Hongbai Bai ◽  
Chunhong Lu ◽  
Shangzhou Li
Keyword(s):  
Energy Absorption ◽  
Impact Loading ◽  
Absorption Rate ◽  
Maximum Load ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Metallic Wire ◽  
Maximum Deformation ◽  
Air Damping ◽  
Stiffness And Damping

In this paper, the stiffness and damping property of entangled metallic wire materials (EMWM) under quasi-static and low-velocity impact loading were investigated. The results reveal that the maximum deformation of the EMWM mainly depends on the maximum load it bears, and that air damping is the main way to dissipate impact energy. The EMWM can absorb more energy (energy absorption rate is over 60%) under impact conditions. The EMWM has excellent characteristics of repetitive energy absorption.

Detailed Flow Analysis Around Blade Tip With a Mie Vane in Case of Different Blade Aspect Ratios and Different Reynolds Numbers

2003 ◽  
Author(s):  
Yukimaru Shimizu ◽  
Edmond Ismaili ◽  
Yasunari Kamada ◽  
Takao Maeda
Keyword(s):  
Reynolds Number ◽  
Research Work ◽  
Flow Analysis ◽  
Reynolds Numbers ◽  
Power Coefficient ◽  
Work Related ◽  
Aspect Ratios ◽  
Power Increase ◽  
Lower Reynolds Number ◽  
Blade Tip

The results of an extensive experimental research work related to the performance of a HAWT with a tip-mounted Mie type vane are presented in this paper. From performance experiments carried out on four sets of blades with varying aspect ratios and for different Reynolds number, it was found that the application of a tip-mounted Mie vane resulted in a larger increase in maximum power coefficient for rotors with smaller aspect ratio and for lower Reynolds number. To investigate further the phenomenon and to explain the relationships found between power increase due to a Mie vane and blade aspect ratios and Reynolds number, detailed flow visualization around blade tip and the Mie vane were performed. It was found that the tendency of the power increase due to a Mie vane was dependent on the size of a corner vortex between blade tip and the downstream extension of the Mie vane.

The Unsteady Behavior of Diffuser Stall in a Centrifugal Compressor With Vaneless Diffuser

2020 ◽  
Author(s):  
Hiroshi Miida ◽  
Kenta Tajima ◽  
Nobumichi Fujisawa ◽  
Yutaka Ohta
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
Rotational Speed ◽  
Flow Region ◽  
Cfd Analysis ◽  
Vaneless Diffuser ◽  
Low Velocity ◽  
Flow Angle ◽  
Boundary Separation ◽  
Low Mass

Abstract The unsteady diffuser stall behavior in a centrifugal compressor with a vaneless diffuser was investigated by experimental and computational analyses. The diffuser stall generated as the mass flow rate decreased. The diffuser stall cell rotated at 25–30% of the impeller rotational speed, with diffuser stall fluctuations observed at 180° from the cutoff. The diffuser stall fluctuation magnitude gradually increased near the cutoff. Based on diffuser inlet velocity measurements, the diffuser stall fluctuations generated near both the shroud and hub sides, and the diffuser stall appeared at 180° and 240° from the cutoff. According to the CFD analysis, the mass flow fluctuations at the diffuser exit showed a low mass flow region, rotating at approximately 25% of the impeller rotational speed. They began at 180° from the cutoff and developed as this region approached the cutoff. Therefore, the diffuser stall could be simulated by CFD analysis. First, the diffuser stall cell originated at 180° from the cutoff by interaction with boundary separation and impeller discharge vortex. Then, the diffuser stall cell further developed by boundary separation accumulation and the induced low velocity area, located at the stall cell center. The low velocity region formed a blockage across the diffuser passage span. The diffuser stall cell expanded in the impeller rotational direction due to boundary separation caused by a positive flow angle. Finally, the diffuser stall cell vanished when it passed the cutoff, because mass flow recovery occurred.

Walking Anchors: When to Fix One or Both Ways?

2019 ◽  
Author(s):  
Daniel Carneiro ◽  
Luciano Franco
Keyword(s):  
Maximum Load ◽  
Load Reduction ◽  
Trial And Error

Abstract Anchors to mitigate pipeline walking often involve very large piles, requiring large crane installation vessels, which bring cost, schedule and HSE risk implications. Optimizing such piles traditionally require substantial FEA effort, and frequently, project decisions are made, and purchase orders are placed based on conservative assumptions. The choice of anchor-to-pipeline connection can significantly influence the anchor sizing. In some cases, allowing some free slide-back displacement when the anchor is being unloaded can substantially reduce the maximum load levels. This paper presents simple analytical calculations that can be used to determine whether this artifice is effective or not for any given condition; how much load reduction can be achieved; and how much slide-back length is required for that. Results for typical, hypothetical pipeline properties are presented. These show that while some cases will see no benefit, in others cases the load can be reduced by over 1 MN by allowing no more than a few centimeters slide-back tolerance. Having the ability to assess multiple options with minimum effort, then use FEA for detailed confirmation (rather than using expensive FEA on a trial and error basis) will allow certain projects to realize significant savings.

Compression after Impact Performance of Composite Stiffened Panels

2011 ◽  
Vol 415-417 ◽  
pp. 2231-2235 ◽  
Author(s):  
Zhe Sun ◽  
Fei Xu ◽  
Wei Xie ◽  
Bo Wang
Keyword(s):  
Structural Damage ◽  
Initial Imperfection ◽  
Maximum Load ◽  
Experimental Results ◽  
Low Velocity Impact ◽  
Thickness Direction ◽  
Low Velocity ◽  
Stiffened Panels ◽  
Velocity Impact ◽  
Compression After Impact

Composite stiffened panels are widely used in the modern aircraft structure with the advantages of light weight, structural efficiency and good crack performance. But the stiffened panels have poor performance at thickness direction, especially for low-velocity impact. First of all, compressive tests were investigated and analyzed for two types of composite stiffened panels, which are integrated specimens and post-impact specimens. And the effect of low-velocity impact to the supporting capacity of composite stiffened panels was researched. Secondly，the finite element model was established to simulate the CAI (Compression After Impact)strength with the equivalent hole method. It is found that the analyze results match the experimental results well. According to the experimental results, structural damage and the maximum load caused by impact energy are scattering. Then the imperfect factors were introduced to reflect the initial imperfection, namely the initial deflection at thickness direction. The effect of different imperfect factors to the maximum load was discussed.

Reliability of bridge structures under wind loading: Consideration of uncertainties of wind load parameters

1990 ◽  
Vol 33 (1-2) ◽  
pp. 385-394 ◽  
Author(s):  
P.H.W. Prenninger ◽  
M. Matsumoto ◽  
N. Shiraishi ◽  
C. Izumi ◽  
Y. Tsukiyama
Keyword(s):  
Wind Load ◽  
Wind Loading ◽  
Bridge Structures
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