STABILITY ANALYSIS OF DUNNAGE FOR TRANSPORTATION OF A STEEL ROLL COIL

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3769-3774 ◽  
Author(s):  
LEE-KU KWAC ◽  
JAE-YEOL KIM ◽  
HANG-WOO KIM ◽  
JAE-HO HAN ◽  
YOUN-SIN LEE

When ironwork, especially steel roll coil, is transported to customers, land transportation and sea transportation are usually used. To transport steel roll coil fast and safe without damaging it, it is necessary that the steel roll coil has to be in stable condition. These days, apitong, which is all imported from overseas, is being used to support the steel roll coil, but because of apitong's rigidity, it damages the coil and when the coil is damaged, it is hard to fix. Due to the fact that recovering damage of the coil is almost impossible, we have to find the new type of dunnage that can substitute the apitong. In this paper, the arrays and the kinds of reinforcements, and rectangular type and trapezoid of dunnage will be talked about. The phenomenon of rolling and the impact when the carrier start moving and stop will be talked about as well. Therefore, we are going to develop a dunnage that does not damage ironwork and has better recovery and softness than existing apitong dunnage.

2007 ◽  
Vol 340-341 ◽  
pp. 1363-1368 ◽  
Author(s):  
Lee Ku Kwac ◽  
Hong Gun Kim ◽  
Hang Woo Kim

The common transportation methods for the consumers of the ironwork such as the steel roll coils manufactured from the steelworks were either by the land transportation or the sea transportation. In order to transport the steel roll coil effectively and safely to the destination, the stability of the steel roll coil which induced the minimum movements during the transportation was strongly required. The basic transportation equipment for the steel roll coil such as the dunnage is made of 100% imported wood known as the apitong. However, the material characteristic such as the rigidity has caused permanent damages to the steel roll coil and the damaged steel roll coils were not easily restorable thus they were unsuitable for other purposes. Therefore, the introduction of new materials manufacturing dunnages which would have a good recovery performance and thus enable the damage prevention or reduction to the steel roll coil or any other products during the transportation is needed. This investigation was to develop the new and improved type of a dunnage from observing the current dunnage in the following areas; the array or the types of reinforcements that established the construction of the dunnage, the dunnage forming shapes of a rectangle and a trapezoid, the direct impacts to dunnage in the presence of vibration when the carrier was moving and stopping, and the critical impact to the dunnage due to the edge loading. Ultimately, the development of new type of dunnage that consisted of characteristics being soft and recoverable than the existing apitong dunnage and induces little or no damages to the steel roll coils are required.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3243
Author(s):  
Shaojian Song ◽  
Peichen Guan ◽  
Bin Liu ◽  
Yimin Lu ◽  
HuiHwang Goh

Impedance-based stability analysis is an effective method for addressing a new type of SSO accidents that have occurred in recent years, especially those caused by the control interaction between a DFIG and the power grid. However, the existing impedance modeling of DFIGs is mostly focused on a single converter, such as the GSC or RSC, and the influence between the RSC and GSC, as well as the frequency coupling effect inside the converter are usually overlooked, reducing the accuracy of DFIG stability analysis. Hence, the entire impedance is proposed in this paper for the DFIG-based WECS, taking coupling factors into account (e.g., DC bus voltage dynamics, asymmetric current regulation in the dq frame, and PLL). Numerical calculations and HIL simulations on RT-Lab were used to validate the proposed model. The results indicate that the entire impedance model with frequency coupling is more accurate, and it is capable of accurately predicting the system’s possible resonance points.


2016 ◽  
Vol 30 (18) ◽  
pp. 1650243 ◽  
Author(s):  
Guanghan Peng ◽  
Li Qing

In this paper, a new car-following model is proposed by considering the drivers’ aggressive characteristics. The stable condition and the modified Korteweg-de Vries (mKdV) equation are obtained by the linear stability analysis and nonlinear analysis, which show that the drivers’ aggressive characteristics can improve the stability of traffic flow. Furthermore, the numerical results show that the drivers’ aggressive characteristics increase the stable region of traffic flow and can reproduce the evolution and propagation of small perturbation.


Author(s):  
Sen Zhang ◽  
Dingxi Wang ◽  
Yi Li ◽  
Hangkong Wu ◽  
Xiuquan Huang

Abstract The time spectral method is a very popular reduced order frequency method for analyzing unsteady flow due to its advantage of being easily extended from an existing steady flow solver. Condition number of the inverse Fourier transform matrix used in the method can affect the solution convergence and stability of the time spectral equation system. This paper aims at evaluating the effect of the condition number of the inverse Fourier transform matrix on the solution stability and convergence of the time spectral method from two aspects. The first aspect is to assess the impact of condition number using a matrix stability analysis based upon the time spectral form of the scalar advection equation. The relationship between the maximum allowable Courant number and the condition number will be derived. Different time instant groups which lead to the same condition number are also considered. Three numerical discretization schemes are provided for the stability analysis. The second aspect is to assess the impact of condition number for real life applications. Two case studies will be provided: one is a flutter case, NASA rotor 67, and the other is a blade row interaction case, NASA stage 35. A series of numerical analyses will be performed for each case using different time instant groups corresponding to different condition numbers. The conclusion drawn from the two real life case studies will corroborate the relationship derived from the matrix stability analysis.


2020 ◽  
Author(s):  
Sari Goldstein Ferber ◽  
Gal Shoval ◽  
Viviana Trezza ◽  
Giorgio Di Lorenzo ◽  
Rodolfo Rossi ◽  
...  

Author(s):  
Begüm Aylin Önder

Corporate social responsibility is one of the activities that goes beyond philanthropy, based on volunteerism in line with the responsibilities of enterprises towards society. This concept, which offers businesses the opportunity to look after and develop their brand image in the eyes of society, has become a necessity, not a choice, especially in today's world. In order to meet social expectations, the effectiveness of static and dynamic advertising messages implemented in all social benefit-based studies for human development such as environment, health and education is very important in terms of ensuring audience communication. In the second half of 2019, people were confined to homes and life came to a standstill all over the world in order to reduce and prevent the impact of the pandemic within the scope of the “New Type Corona Virus” (COVID-19) measures, which are from the sars-cov-2 coronavirus family, which is spreading rapidly globally starting from Wohan, Hubei Province, China. As a basic protection module for humanity against corona virus, it has incorporated the concept of social distancing into their lives in order to reduce the contact of staying at home and increasing hygiene, except in mandatory situations. During this extraordinary period, many brands on a global scale have included the concept of “social distance” in their advertising messages with the awareness of corporate social responsibility and have started to inform and educate the community about this issue by emphasizing the importance of the process. Within the scope of this research, advertising designs prepared by brands acting with corporate social responsibility awareness through the concept of social distancing during the Pandemic period were discussed and how the meaning structures behind the messages were created and transmitted. The research is limited to 3 (three) advertising designs determined by the 'judicial sampling' method (selective method). In the sample of the study, advertising narratives of brands in different sectors were explained in general framework and similar and different aspects of messages were uncovered by performing comparative analysis between messages in line with the findings obtained from the narratives. In this context, it was determined that the contrasts of “pessimism and optimism, hope and despair, happiness and unhappiness, death and life, strong and powerless, youth and old age, unity/togetherness and separation, struggle and defeat, nature and culture” were constructed as the main discourse.


2019 ◽  
Vol 91 (3) ◽  
pp. 428-436 ◽  
Author(s):  
Agnieszka Kwiek

Purpose The purpose of this research is a study into a mathematical approach of a tailless aircraft dynamic stability analysis. This research is focused on investigation of influence of elevons (elevator) on stability derivatives and consequently on the aircraft longitudinal dynamic stability. The main research question is to determine whether this impact should be taken into account on the conceptual and preliminary stage of the analysis of the longitudinal dynamic stability. Design/methodology/approach Aerodynamic coefficients and longitudinal stability derivatives were computed by Panukl (panel methods). The analysis of the dynamic stability of the tailless aircraft was made by the Matlab code and SDSA package. Findings The main result of the research is a comparison of the dynamic stability of the tailless aircraft for different approaches, with and without the impact of elevator deflection on the trim drag and stability derivatives. Research limitations/implications This paper presents research that mostly should be considered on the preliminary stage of aircraft design and dynamic stability analysis. The impact of elevons deflection on the aircraft moment of inertia has been omitted. Practical implications The results of this research will be useful for the further design of small tailless unmanned aerial vehicles (UAVs). Originality/value This research reveals that in case of the analysis of small tailless UAVs, the impact of elevons deflection on stability derivatives is bigger than the impact of a Mach number. This impact should be taken into consideration, especially for a phugoid mode.


Author(s):  
Maryam Salahshour ◽  
Halina Mohamed Dahlan ◽  
Noorminshah A. Iahad

Social networking tools have become an integral part of our daily lives. Recently, a new type of Social Networking Sites (SNSs) namely Academic Social Networking sites (ASNSs) has attracted global users. There is perceived usefulness on the impact of ASNSs on patterns of academic research activities. However, it remains unclear why some researchers do not use ASNSs at all. The purpose of this paper is therefore to explore the ASNSs usage among Malaysian academic researchers and to investigate benefits, specific purpose, drivers and barriers of using ASNSs. A total of 210 completed cases were collected through paper-based and online-based questionnaire. In order to show the outcome of the research, descriptive interpretation of data is performed. The overall findings of this research indicate that there is low rate of ASNSs usage among researchers. In addition, the results show that colleagues, attitude toward technology and communication benefits are the drivers to use ASNSs and trust, privacy and security are the common barriers regarding to use ASNSs.


2018 ◽  
Vol 38 (2) ◽  
pp. 242-252
Author(s):  
Jianrong Yang ◽  
Zhiyu Zhang

A new concept of a flexible rock-shed is presented for protection of the railway from falling rocks. The flexible rock-shed is made of flexible nets connected by specific spring spacer bars to an array of reinforced concrete portable frames which are linked by a longitudinal steel tube truss. To evaluate the performance of the flexible rock-shed, experimental and numerical studies are carried out in the present study. Impact tests are conducted on a full-scale partial model of the prototype structure when it is subjected to a falling block of 340 kg. The impact time interval, maximum deflection of the flexible net, tensile forces in the supporting ropes, and axial strains of spring spacer bars are recorded. To further examine the dynamic behavior of the flexible rock-shed, numerical simulations are also carried out by using the explicit finite element code ANSYS/LS-DYNA. It is found that the numerical results coincide well with the experimental data and both the numerical and experimental studies reveal that the structure can withstand impact energy of 50 kJ with all the materials working in the elastic range. The structural details are improved and the basis for the design and construction of similar structures in the future is provided.<br>


2021 ◽  
pp. 46-54
Author(s):  
Muhammad Amin Syam ◽  
Heriyanto Heriyanto ◽  
Hamzah Umar

PT Belayan Internasional Coal is an open-pit system mining company, one of its geotechnical activities is the construction of the slopes. Slope stability analysis used the Bishop Simplified method to obtain the value of the dynamic safety factor (≥ 1,1). Currently, the value of the Safety Factor (FK) is an indicator in determining whether the slope is stable or not. The parameters used in the slope stability analysis are the physical and mechanical properties of the rock, namely weight (ɣ), cohesion value (c), and internal shear angle (∅). From the results of dynamic overall slope calculations, the recommended overall slope is constructed with an individual slope angle of 55°, a bench width of 5 meters, a height of 10 meters, and the number of individual slopes of 8 slopes. This design will produce dimensions of the overall slope with 41° slope angle, 80 meters high, and has a dynamic safety factor value of 1,102 with the water-saturated condition. Thus, the slopes are in stable condition.


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