Effect of Coal Loading Conditions on Structural Characteristics of LFTS

2019 ◽  
Author(s):  
Hiroaki Eto ◽  
Koji Iizuka ◽  
Ryo Nishigochi ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Loading Condition ◽  
Local Stress ◽  
Asia Pacific ◽  
Linear Potential ◽  
Detailed Model ◽  
Local Stress Concentration ◽  
East Kalimantan ◽  
Wave Response ◽  
Bulk Carriers

Abstract Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, Large-Scale Floating Coal Transshipment Station (LFTS) was proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. LFTS can store coal equivalent to five times the capacity of one bulk carrier (total 500,000T), and can accommodate 2 bulk carriers at the same time during offloading. The scale of LFTS is 590m × 160m. The LFTS has a flat spread and the elastic behavior becomes the dominant Structure. The upper part of the LFTS is different rigidity partly because the partition wall to be loaded by dividing the coal into each quality is provided. Loaded coal not only changes the draft of the LFTS but also greatly deforms the LFTS and is expected to cause local stress concentration on the structural members. Therefore, this paper investigates wave response characteristics and stress characteristics with the coal loading of the LFTS, and then evaluation of structural strength by limit state design method. In this study, linear potential theory and the finite element method (FEM) were used to analyze the static hydroelastic motion under various coal loading condition and wave response of LFTS. And, to grasp the local stress concentration occurring inside the LFTS by using the response results, a detailed model modeling a complicated internal structure was prepared. Zooming analysis which is a method of giving the deformation result by the whole model of LFTS as forced displacement to the local detailed model was carried out. As a result, depending on the coal loading condition and wave conditions, it became clear that LFTS will be in a tough situation.

Effect of Coal Loading Conditions on Elastic Behavior of Large-Scale Floating Transshipment Station (LFTS)

2017 ◽  
Author(s):  
Hiroaki Eto ◽  
Chiaki Sato ◽  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Mitsuru Kubota ◽  
...  
Keyword(s):  
Large Scale ◽  
Static Stability ◽  
Asia Pacific ◽  
Elastic Behavior ◽  
Linear Potential ◽  
Loading Conditions ◽  
East Kalimantan ◽  
Sea Bed ◽  
Bulk Carriers ◽  
Linear Potential Theory

Japan imports coal from Indonesia, the main coal supplier in the Asia-Pacific region. Effective and efficient movement of coal down the Markham River in East Kalimantan, Indonesia, and onto bulk carriers is challenging because the river is shallow and generally cannot accommodate bulk carriers. The primary transportation system comprises small barges that are shuttled back and forth between the inland barge ports along the river and bulk carriers offshore. This system is very time-consuming. This paper proposes a large-scale floating coal transshipment station (LFTS) for loading, storing, and offloading coal. It will act as a relay base for barges and bulk carriers. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. The proposed LFTS can store 5 times the capacity of one bulk carrier and can accommodate 2 bulk carriers at the same time during offloading. The LFTS is compartmentalized by bulkheads to segregate coal according to quality. This paper discusses LFTS static stability and its elastic deformation characteristics during coal loading operations. In this study, linear potential theory and the finite element method (FEM) were used to analyze the LFTS static hydroelastic motion. Due to the compartments, coal loading conditions can vary significantly and affect the local static deflection, so we modeled the overall deformation and rigidity under various operational scenarios. The results were compared to the allowable material stress to identify conditions that will produce material failure. Moreover, we evaluated operation in the shallow Kalimantan River, since the weight of loaded coal deepens the LFTS draft, reducing the clearance between the LFTS and sea bed. We found that this reduced clearance and large added mass impact the natural frequency of the LFTS.

Determination of DC06+ZE Sheet Crack Cause

2016 ◽  
Vol 368 ◽  
pp. 121-125
Author(s):  
Pavel Kejzlar ◽  
Tomáš Pilvousek ◽  
Michal Tregler
Keyword(s):  
Stress Concentration ◽  
Tensile Stress ◽  
Deep Drawing ◽  
Crack Formation ◽  
Local Stress ◽  
Local Deformation ◽  
Local Stress Concentration ◽  
Bcc Lattice ◽  
Hard Particles

The present work deals with determination of the cause of crack occurring in a part of car body manufactured from deep-drawing sheet. UHR-SEM, EDS, EBSD and measurement of microhardness were used for evaluation of the structure, local deformation and crack formation mechanism. A material analysis discovered foreign particles in the material. These particles were identified as MgAl2O4 with BCC lattice. The occurrence of these hard particles led to local stress concentration, decrease in mechanical strength and sheet breach due to tensile stress during deformation.

Permeability Improvement Technology of Directional Hydraulic Fracturing in Low Permeability

2014 ◽  
Vol 599-601 ◽  
pp. 385-390 ◽  
Author(s):  
Xue Xi Chen ◽  
Rui Qing Bi ◽  
Wen Guang Jin ◽  
Yong Xu
Keyword(s):  
Stress Concentration ◽  
Hydraulic Fracturing ◽  
Maximum Concentration ◽  
Local Stress ◽  
Field Application ◽  
Low Permeability ◽  
Pressure Relief ◽  
Local Stress Concentration ◽  
Directional Hydraulic Fracturing ◽  
Better Than

According to the conventional fracturing could easily lead to the local stress concentration of coal, the effect of pressure relief and permeability improvement is not ideal. The mechanism of directional hydraulic fracturing is analyzed and the parameters such as the layout of directional hole, the fracturing hole sealing, the minimum cracking pressure are discussed, then the field application tests are carried out. The results show that the directional hydraulic fracturing effect is better than that of ordinary fracturing hole and the maximum concentration and the average drainage scalar is respectively 3.75 times and 4 times of the ordinary hole pumping gas fracturing effects. The effect of permeability improvement is remarkable.

Stress Intensity Factor for Corner Cracks of Pressurized Tees

1980 ◽  
Vol 102 (1) ◽  
pp. 121-123 ◽  
Author(s):  
M. A. Mohamed ◽  
J. Schroeder
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Stress Concentration ◽  
Intensity Factor ◽  
Local Stress ◽  
Numerical Techniques ◽  
Intensity Factors ◽  
Local Stress Concentration ◽  
Corner Cracks ◽  
Good Agreement

A method based on local stress concentration is employed to estimate stress intensity factors for corner cracks at the crotch corner of pressurized tees. The method yields results which are in good agreement with data obtained using other advanced numerical techniques.

Stress-Chemistry Mechanism of Mortars Made with Steel Slag Sand

2010 ◽  
Vol 163-167 ◽  
pp. 899-903
Author(s):  
Yun Xia Lun ◽  
Shao Shun Liu ◽  
Ming Kai Zhou ◽  
Xiao Fan Liu
Keyword(s):  
Stress Concentration ◽  
Volume Expansion ◽  
Steel Slag ◽  
Local Stress ◽  
Local Stress Concentration ◽  
Chemistry Method ◽  
Expansion Behavior ◽  
Volume Increment ◽  
Mineral Components ◽  
Free Cao

A stress-chemistry method was used to investigate the expansion behavior of mortars made with steel slag sand (SSM). The results indicated that periclase and free CaO were the main mineral components resulted in expansion of SSM by means of volume increment and local stress concentration after hydration. So it can be concluded that stress concentration arised from enrichment and uneven distribution of expansile mineral components was the main reason resulted in the volume expansion of SSM. Model of expansion of SSM was built according to the characteristics of crack and types of versicolor particles.

Sign in / Sign up

Export Citation Format

Share Document