Line-finite-element implementation for driven steel H-piles in layered sands considering post-driving residual stresses

2020 ◽  
pp. 136943322097814
Author(s):  
Weihang Ouyang ◽  
Jianhong Wan ◽  
Si-Wei Liu ◽  
Xueyou Li
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Cost Effective ◽  
Deep Foundation ◽  
Practical Applications ◽  
Finite Element Implementation ◽  
Total Potential ◽  
Current Design ◽  
Successful Design ◽  
Derivation Procedure

Driven Steel H-piles are commonly used in the deep foundation of being cost-effective and easy in workmanship. The post-driving residual stresses acting on the pile could be large when being driven in cohesionless sands, significantly affecting its compressive strength. Current design methods, mostly based on the empirical assumptions of using safety factors, are unable to consider the post-driving residual stresses on piles accurately and usually very conservative in practical applications. Such consideration is further complicated when the pile is embedded in layered sands. Moreover, the soil-structure interaction (SSI) between pile and ground medium is usually complicated in the analysis and should be appropriately considered in a successful design. This paper proposes a line-finite-element implementation method, based on the Euler-Bernoulli pile element formulations, for robustly and efficiently analyzing the driven steel H-piles in layered sands with explicitly modelling the SSI. The effects resulting from the post-driving residual stresses are considered in the total potential energy equation for generating the secant relations. The derivation procedure is elaborated with details. Consequentially, verification examples are given for validating the accuracy of the proposed method. This work would be helpful for improving the numerical efficiency and accuracy for designing the steel H-piles in layered sands.

Finite Element Modeling of Hard Roller Burnishing: An Analysis on the Effects of Process Parameters Upon Surface Finish and Residual Stresses

2007 ◽  
Vol 129 (4) ◽  
pp. 705-716 ◽  
Author(s):  
Partchapol Sartkulvanich ◽  
Taylan Altan ◽  
Francisco Jasso ◽  
Ciro Rodriguez
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Process Parameters ◽  
Surface Finish ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Cost Effective ◽  
Machined Surface ◽  
Fem Model ◽  
Roller Burnishing

Hard roller burnishing is a cost-effective finishing and surface enhancement process where a ceramic ball rolls on the machined surface to flatten the roughness peaks. The ball is supported and lubricated by hydrostatic fluid in a special tool holder. The process not only improves surface finish but also imposes favorable compressive residual stresses in functional surfaces, which can lead to long fatigue life. Most research in the past focused on experimental studies. There is still a special need for a reliable finite element method (FEM) model that provides a fundamental understanding of the process mechanics. In this study, two-dimensional (2D) and three-dimensional FEM models for hard roller burnishing were established. The developed 2D FEM model was used to study the effects of process parameters (i.e., burnishing pressure, feed rate) on surface finish and residual stresses. The simulation results were evaluated and compared to the experimental data. Results show that the established FEM model could predict the residual stresses and provided useful information for the effect of process parameters. Both FEM and experiments show that burnishing pressure is the most influence, where high burnishing pressure produces less roughness and more compressive residual stress at the surface.

Size effect on axial behavior of concrete-filled box columns

2018 ◽  
Vol 21 (13) ◽  
pp. 2068-2078 ◽  
Author(s):  
Ming-Chang Wu ◽  
Chien-Chung Chen ◽  
Cheng-Cheng Chen
Keyword(s):  
Finite Element ◽  
Size Effect ◽  
Axial Loading ◽  
Element Analysis ◽  
Cross Sectional ◽  
Practical Applications ◽  
Axial Capacity ◽  
Current Design ◽  
Axial Behavior ◽  
Box Columns

The use of concrete-filled box columns could provide an economical alternative to building and bridge construction. Past experimental results showed that current building codes provided an adequate accuracy in determining axial capacity of such composite members. However, the sizes of the previously studied test specimens were mostly smaller than those for practical applications. As the column size increases, the size effect may become significant. Therefore, the applicability of extrapolating those test results to larger concrete-filled box columns needs to be justified. This study was devoted to investigating the potential size effect on axial behavior of concrete-filled box columns. Six short square concrete-filled box columns, with cross-sectional dimensions ranging from 300 to 750 mm, were tested under axial loading. Comparisons between experimental and analytical results were presented. It was observed that the size effect was prominent for the concrete-filled box columns studied herein. The results of this study showed that current design codes overestimated the axial capacity of the test columns with a dimension of 750 mm. In addition, finite element simulations of the axially loaded specimens were conducted to investigate the stress–strain behaviors of the concrete enclosed in different sizes of steel box columns. Results from the finite element analysis suggested that the larger steel box columns were less effective in enhancing the compressive strength of the enclosed concrete than smaller steel box columns.

Verification of Riser Load Stacked on Stanchion Induced by Self Weight and Hull Acceleration

2016 ◽  
Author(s):  
So-Yoon Kim ◽  
Ki-Sub Choi ◽  
Myung-Hyun Kim
Keyword(s):  
Finite Element ◽  
Cost Effective ◽  
Offshore Structures ◽  
Operating Conditions ◽  
Long Distance ◽  
Element Analysis ◽  
Design Guideline ◽  
Current Design ◽  
Rational Calculation ◽  
Design Loads

Recently offshore installations for the development of gas and oil resources have moved toward the deeper sea and harsher environment. In this regard, there are increasing operational demands for offshore structures performing in depth with long distance transportation. Drill ships are one of the representative structures commonly employed for the development of energy resources in deep sea. However, these drilling systems are exposed to the various loadings and harsh environment. Therefore, current design code and standards are very conservative to take account of such conditions. The riser stanchions for the staking the riser are one of the structure that installed on the riser deck platform of drill ship. In transit or operating conditions, the riser load is applied to the stanchion. Therefore, the required strength of stanchion enough to withstand the riser loads and should be designed to meet owner and classification requirements. However, the currently practice design loads, which has been widely used in the shipyard and manufacture industries are too conservative resulting in excessive structural weight. In this regard, the purpose of this study is to propose a rational calculation procedure for the design of cost effective and lightweight stanchion structures. This study used a pyramid stacking type of arrangement for the investigation of the effects of stanchion by riser self-weight and hull acceleration. First, the riser loads based on the current conventional design practice is compared with the results obtained by non-linear finite element analysis. In the finite element simulation, contact and damping conditions of stacked risers are explicitly considered. Second, the calculation of riser loads in transverse direction is not easy due to the difficulty associated with considering transverse hull acceleration. Therefore, a new design guideline is presented in a strength calculation of the stanchion structure against to the estimated design loads.

scholarly journals Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

2021 ◽  
Vol 13 (15) ◽  
pp. 8421
Author(s):  
Yuan Gao ◽  
Jiandong Huang ◽  
Meng Li ◽  
Zhongran Dai ◽  
Rongli Jiang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Efficiency ◽  
Low Cost ◽  
Chemical Activation ◽  
Cost Effective ◽  
Coal Gangue ◽  
Order Kinetic ◽  
Practical Applications ◽  
Detailed Structural Analysis ◽  
Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

scholarly journals Finite element investigation of lamination-induced curl due to residual stresses

2021 ◽  
pp. 100034
Author(s):  
Manogna Jambhapuram ◽  
James K. Good ◽  
Aurélie Azoug
Keyword(s):  
Finite Element ◽  
Residual Stresses

scholarly journals An enhancement of the current design concepts for the improved consideration of residual stresses in fatigue-loaded welds

2021 ◽  
Vol 65 (4) ◽  
pp. 643-651
Author(s):  
Th. Nitschke-Pagel ◽  
J. Hensel
Keyword(s):  
Residual Stresses ◽  
State Of The Art ◽  
High Strength Steels ◽  
High Strength ◽  
Design Tools ◽  
Design Concepts ◽  
Treatment Processes ◽  
Real Distribution ◽  
Current Design ◽  
Reliable Knowledge

AbstractThe consideration of residual stresses in fatigue-loaded welds is currently done only qualitatively without reliable knowledge about their real distribution, amount and prefix. Therefore, the tools which enable a more or less unsafe consideration in design concepts are mainly based on unsafe experiences and doubtful assumptions. Since the use of explicitly determined residual stresses outside the welding community is state of the art, the target of the presented paper is to show a practicable way for an enhanced consideration of residual stresses in the current design tools. This is not only limited on residual stresses induced by welding, but also on post-weld treatment processes like HFMI or shot peening. Results of extended experiments with longitudinal fillet welds and butt welds of low and high strength steels evidently show that an improved use of residual stresses in fatigue strength approximation enables a better evaluation of peening processes as well as of material adjusted welding procedures or post-weld stress relief treatments. The concept shows that it is generally possible to overcome the existing extremely conservative but although unsafe rules and regulations and may also enable the improved use of high strength steels.

scholarly journals Development of Nonlinear Finite Element Models of Mortar-Free Interlocked Single Block Column Subjected to Lateral Loading

2021 ◽  
Author(s):  
Furqan Qamar ◽  
Shunde Qin
Keyword(s):  
Finite Element ◽  
Failure Load ◽  
Cost Effective ◽  
Nonlinear Finite Element ◽  
World Population ◽  
Bond Failure ◽  
Lateral Resistance ◽  
Lateral Strength ◽  
Parametric Studies ◽  
Single Block

AbstractAround the globe, the need for additional housing, due to the increase in world population, has led to the exploration of more cost effective and environmentally friendly forms of construction. Out of many technologies found, mortar-free interlocked masonry systems were developed to eliminate the deficiency of traditional masonry. For such systems against earthquakes, lateral resistance can be enhanced with plaster. But there is a need to further improve the performance of plaster in mortar-free interlocking walls for better ductility. The objective of this study is to develop nonlinear finite element (NLFE) models to explore the likely failure mechanism (e.g. bond failure) of such systems and to do parametric studies more cheaply than constructing many walls. Lateral failure load, load–displacement curves and crack patterns were compared with the experimental results. Parametric studies involving variation in block and plaster compressive strength and plaster thickness were undertaken using TNO DIANA NLFE models. A 150% increase in thickness of plaster only resulted in 28% increase in failure load, and column thickness can be reduced to theoretical 25 mm of blocks with 8 mm of plaster and yet exceed the lateral strength of a 150-mm-thick unplastered column. A cost analysis was also carried out, based on NLFE models, and showed that fibrous plastered column with 25-mm-thickness blocks gave equivalent performance to the 150-mm-thick unplastered column with 67% cost saving.

scholarly journals Voronoi diagram and Monte-Carlo simulation based finite element optimization for cost-effective 3D printing

2021 ◽  
Vol 50 ◽  
pp. 101301
Author(s):  
A.Z. Zheng ◽  
S.J. Bian ◽  
E. Chaudhry ◽  
J. Chang ◽  
H. Haron ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Finite Element ◽  
Monte Carlo ◽  
3D Printing ◽  
Voronoi Diagram ◽  
Cost Effective ◽  
Simulation Based

scholarly journals Enhanced Thermoelectric Performance of n-Type Bi2Se3 Nanosheets through Sn Doping

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1827
Author(s):  
Mengyao Li ◽  
Yu Zhang ◽  
Ting Zhang ◽  
Yong Zuo ◽  
Ke Xiao ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Cost Effective ◽  
Low Grade ◽  
Hot Press ◽  
Processing Technologies ◽  
Sn Doping ◽  
Practical Applications ◽  
Alternative Materials ◽  
The Cost ◽  
Low Grade Heat

The cost-effective conversion of low-grade heat into electricity using thermoelectric devices requires developing alternative materials and material processing technologies able to reduce the currently high device manufacturing costs. In this direction, thermoelectric materials that do not rely on rare or toxic elements such as tellurium or lead need to be produced using high-throughput technologies not involving high temperatures and long processes. Bi2Se3 is an obvious possible Te-free alternative to Bi2Te3 for ambient temperature thermoelectric applications, but its performance is still low for practical applications, and additional efforts toward finding proper dopants are required. Here, we report a scalable method to produce Bi2Se3 nanosheets at low synthesis temperatures. We studied the influence of different dopants on the thermoelectric properties of this material. Among the elements tested, we demonstrated that Sn doping resulted in the best performance. Sn incorporation resulted in a significant improvement to the Bi2Se3 Seebeck coefficient and a reduction in the thermal conductivity in the direction of the hot-press axis, resulting in an overall 60% improvement in the thermoelectric figure of merit of Bi2Se3.

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