Analytical Plastic Capacity Formulation for Plates Subject to Ice Loads and Similar Types of Patch Loadings

2006 ◽  
Author(s):  
Ha˚vard Nyseth ◽  
Gabriel Holtsmark
Keyword(s):  
Load Capacity ◽  
Plate Bending ◽  
Element Analysis ◽  
Yield Line Theory ◽  
Geometry Configuration ◽  
Line Theory ◽  
Patch Load ◽  
Ice Loads ◽  
Patch Loading ◽  
Capacity Formulation

The response of plates subjected to patch loads with length/ height less than the dimensions of the plate field is of importance for the design of hulls strengthened for operation in ice covered waters and other comparable types of loading. An analytical plastic capacity formulation for plates subjected to patch loading of any rectangular geometry configuration has been derived, which from comparison with nonlinear finite element analysis is seen implicitly to limit the permanent deflection to be up to 0,40% of the frame spacing. The analytically derived formulations for the plastic bending based load capacity are based on yield line theory. Expressions for single and multiple patch loads are included, where the derivation is based on the assumption that the response for a single patch load is equal to the response from a sequence of identical patch loads located within the same plate field, and spaced a certain minimum distance apart. The expressions may serve as basis for rule requirements for plates subject to ice loads and other types of patch loads. For the considered longitudinally and transversely stiffened plate cases, nonlinear FE calculations show that the proposed plate bending based load capacity formulations generally give rise to permanent deformations in the plate up to 0.40% of the frame spacing, when the plate model analyzed is extended to include adjacent plate fields. Comparisons of nonlinear FE calculations show the pressure-deformation relationship of the single and repeated load patch to be the same within the range of permanent deformations considered. Comparison of the analytically derived plate formula with DNV Arctic Rules and Finnish-Swedish Ice Class Rules (FSICR) indicates that the plate formula of the DNV/FSICR gives similar results for the same load levels. The analytically derived formula, however, provides a more consistent utilization of the plate bending based capacity that is valid for a wider range of patch load geometries. Comparison of the IACS Polar Class (PC) Rules formulation indicates that the IACS plate formulation is increasingly non-conservative for small patch lengths, and that the application should be restricted to cover larger patch lengths only, e.g. l/s > 1,0.

A Comparative Study on the Plastic Formulations of Ship Shell Plating Under Patch Loading

2008 ◽  
Author(s):  
Lin Hong ◽  
Jo̸rgen Amdahl
Keyword(s):  
Finite Element ◽  
Comparative Study ◽  
Permanent Deformation ◽  
Nonlinear Finite Element ◽  
Limited Area ◽  
Resource Exploitation ◽  
Limit States ◽  
Patch Load ◽  
Ice Loads ◽  
Patch Loading

The purpose of the present study is to further develop the response formulation of ship shell plating under general patch loading, considering the effect of finite, permanent deformation. A comparative study is conducted between various formulations for the load-carrying capacity of laterally patch loaded plates with the aid of nonlinear finite element method. The increasing public interest of transportation and resource exploitation in Arctic area gives rise to advances in ice strengthening of ship structures. As a result, the subject of ship shell plating under ice loads has been extensively studied. Similar to ice loads, wave slamming loads, wheel loads of vehicles and accidental loads, e.g. collision and grounding, are all likely to take place over a limited area of the plate, and can be termed as ‘patch loading’. Consequently, the resistance of ship shell plating under ‘patch loading’ is of significant interest. In this study, a recently developed plastic formulation for patch loaded plates is further extended for general patch loading condition, i.e. patch load with limited extension in both length and height direction. After a brief review of the development of the response and design formulations for plates under uniform lateral load and patch load, comparative studies are made in cases of limited and finite permanent deformation with the aid of nonlinear finite element methods. By allowing a certain level of permanent deformation, significant weight savings can be achieved. Some main findings will be concluded from the comparative study. The present formulation may be used as a versatile tool for predicting the resistance of plates under various types of patch loads, notably when finite, permanent deformations are accepted, e.g. in the Accidental (Abnormal) Limit States design.

scholarly journals Experimental study on static response of prefabricated concrete bulb-tee bridge girder flange-to-flange connections

2021 ◽  
Author(s):  
Siyin Tu
Keyword(s):  
Experimental Study ◽  
Bridge Deck ◽  
Ultimate Load ◽  
Load Capacity ◽  
Wheel Load ◽  
Ultimate Load Capacity ◽  
Yield Line Theory ◽  
Line Theory ◽  
Bridge Girder ◽  
Ultimate Load Carrying Capacity

Prefabricated concrete Deck Bulb-Tee (DBT) bridge girder system requires precast girder flanges to be connected and formed bridge deck at site. In this study, a new bridge deck slab flange to flange connection system for precast DBT girders has been investigated. Two types of moment transferring connection and another two types of intermittent bolted connection were developed. A total of four full-scale bridge DBTgirders for the developed connection details were fabricated and then tested to collapse under simulated wheel load. This thesis reports on an experimental study on static behavior and ultimate load carrying capacity of bridge Deck Bulb-Tee girders jointed with proposed connection detail and technology. structural behavior, including stress and strain, crack formation and propagation, deflection, failure mode, and ultimate load capacity, has been identified. Experimental results are compared to those obtained using the Yield-Line Theory and the available Punching Shear Equations.

scholarly journals Assessing fragility of a reinforced concrete element to snow avalanches using a non-linear dynamic mass-spring model

2018 ◽  
Vol 18 (9) ◽  
pp. 2507-2524
Author(s):  
Philomène Favier ◽  
David Bertrand ◽  
Nicolas Eckert ◽  
Isabelle Ousset ◽  
Mohamed Naaim
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Response ◽  
Fragility Curves ◽  
Dynamic Pressure ◽  
Concrete Element ◽  
Element Analysis ◽  
Yield Line Theory ◽  
Pressure Fields ◽  
Line Theory ◽  
Mass Spring

Abstract. This paper presents an assessment of the fragility of a reinforced concrete (RC) element subjected to avalanche loads, and more generally to dynamic pressure fields applied orthogonally to a wall, within a reliability framework. In order to obtain accurate numerical results with supportable computation times, a light and efficient Single-Degree-of-Freedom (SDOF) model describing the mechanical response of the RC element is proposed. The model represents its dynamic mechanical response up to failure. Material non-linearity is taken into account by a moment–curvature approach, which describes the overall bending response. The SDOF model is validated under quasi-static and dynamic loading conditions by comparing its results to alternative approaches based on finite element analysis and the yield line theory. Following this, the deterministic SDOF model is embedded within a reliability framework to evaluate the failure probability as a function of the maximal avalanche pressure reached during the loading. Several reliability methods are implemented and compared, suggesting that non-parametric methods provide significant results at a moderate level of computational burden. The sensitivity to material properties, such as tensile and compressive strengths, steel reinforcement ratio, and wall geometry is investigated. The effect of the avalanche loading rate is also underlined and discussed. Finally, the obtained fragility curves are compared with respect to the few proposals available in the snow avalanche engineering field. This approach is systematic and will prove useful in refining formal and practical risk assessments. It could be applied to other similar natural hazards, which induce dynamic pressure fields onto the element at risk (e.g., mudflows, floods) and where potential inertial effects are expected and for which fragility curves are also lacking.

scholarly journals Experimental study on static response of prefabricated concrete bulb-tee bridge girder flange-to-flange connections

2021 ◽  
Author(s):  
Siyin Tu
Keyword(s):  
Experimental Study ◽  
Bridge Deck ◽  
Ultimate Load ◽  
Load Capacity ◽  
Wheel Load ◽  
Ultimate Load Capacity ◽  
Yield Line Theory ◽  
Line Theory ◽  
Bridge Girder ◽  
Ultimate Load Carrying Capacity

Prefabricated concrete Deck Bulb-Tee (DBT) bridge girder system requires precast girder flanges to be connected and formed bridge deck at site. In this study, a new bridge deck slab flange to flange connection system for precast DBT girders has been investigated. Two types of moment transferring connection and another two types of intermittent bolted connection were developed. A total of four full-scale bridge DBTgirders for the developed connection details were fabricated and then tested to collapse under simulated wheel load. This thesis reports on an experimental study on static behavior and ultimate load carrying capacity of bridge Deck Bulb-Tee girders jointed with proposed connection detail and technology. structural behavior, including stress and strain, crack formation and propagation, deflection, failure mode, and ultimate load capacity, has been identified. Experimental results are compared to those obtained using the Yield-Line Theory and the available Punching Shear Equations.

scholarly journals Behavior of Offshore Pile in Calcareous Sand—Case Study

2021 ◽  
Vol 9 (8) ◽  
pp. 839
Author(s):  
Tarek N. Salem ◽  
Nadia M. Elkhawas ◽  
Ahmed M. Elnady
Keyword(s):  
Load Capacity ◽  
High Stress ◽  
Embedment Depth ◽  
Shear Stresses ◽  
Northern Coast ◽  
Compression Tests ◽  
Calcareous Sand ◽  
Element Analysis ◽  
Mixing Ratios

The erosion of limestone and calcarenite ridges that existed parallel to the Mediterranean shoreline forms the calcareous sand (CS) formation at the surface layer of Egypt's northern coast. The CS is often combined with broken shells which are considered geotechnically problematic due to their possible crushability and relatively high compressibility. In this research, CS samples collected from a site along the northern coast of Egypt are studied to better understand its behavior under normal and shear stresses. Reconstituted CS specimens with different ratios of broken shells (BS) are also investigated to study the effect of BS ratios on the soil mixture strength behavior. The strength is evaluated using laboratory direct-shear and one-dimensional compression tests (oedometer test). The CS specimens are not exposed to significant crushability even under relatively high-stress levels. In addition, a 3D finite element analysis (FEA) is presented in this paper to study the degradation offshore pile capacity in CS having different percentages of BS. The stress–strain results using oedometer tests are compared with a numerical model, and it gave identical matching for most cases. The effects of pile diameter and embedment depth parameters are then studied for the case study on the northern coast. Three different mixing ratios of CS and BS have been used, CS + 10% BS, CS + 30% BS, and CS + 50% BS, which resulted in a decrease of the ultimate vertical compression pile load capacity by 8.8%, 15%, and 16%, respectively.

Progressive failure analysis of scarf-repaired composite laminate based on damage constitutive model

2016 ◽  
Vol 233 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Laminate ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Three Dimensional ◽  
Zone Model ◽  
State Variables ◽  
Element Analysis

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.

Modeling and experimental research on engaging characteristics of wet clutch

2019 ◽  
Vol 71 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Yanzhong Wang ◽  
Yuan Li ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Contact Surface ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Lubricating Oil ◽  
Centrifugal Effect ◽  
Element Analysis ◽  
Content Type ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Engagement Process

PurposeTo gain in-depth understandings of engaging characteristics, the purpose of this paper is to improve the model of wet clutches to predict the transmitted torque during the engagement process.Design/methodology/approachThe model of wet clutch during the engagement process took main factors into account, such as the centrifugal effect of lubricant, permeability of friction material, slippage factor of lubricant on contact surface and roughness of contact surface. Reynolds’ equation was derived to describe the hydrodynamic lubrication characteristics of lubricant film between the friction plate and the separated plate, and an elastic-plastic model of the rough surfaces contact based on the finite element analysis was used to indicate the loading force and friction torque of the contact surface.FindingsThe dynamic characteristics of wet clutch engagement time, relative speed, hydrodynamic lubrication of lubricating oil, rough surface contact load capacity and transfer torque can be obtained by the wet clutch engagement model. And the influence of the groove shape and depth on the engaging characteristics is also analyzed.Originality/valueThe mathematical model of the wet clutch during the engagement process can be used to predict the engaging characteristics of the wet clutch which could be useful to the design of the wet clutch.

ELASTO-PLASTIC PROPERTIES OF Mo-MODIFIED Ti DEDUCED FROM INDENTATION TESTS AND FINITE ELEMENT ANALYSIS

2019 ◽  
Vol 26 (07) ◽  
pp. 1850225
Author(s):  
YONG MA ◽  
ZHAO YANG ◽  
SHENGWANG YU ◽  
BING ZHOU ◽  
HONGJUN HEI ◽  
...  
Keyword(s):  
Finite Element ◽  
Surface Treatment ◽  
Load Capacity ◽  
Indentation Test ◽  
Element Analysis ◽  
Plastic Properties ◽  
Polynomial Expression ◽  
Indentation Tests ◽  
Graded Material ◽  
Micro Indentation

The aim of this paper is to establish an approach to quantitatively determine the elasto-plastic parameters of the Mo-modified Ti obtained by the plasma surface alloying technique. A micro-indentation test is conducted on the surface under 10[Formula: see text]N. Considering size effects, nanoindentation tests are conducted on the cross-section with two loads of 6 and 8[Formula: see text]mN. Assuming nanoindentation testing sublayers are homogeneous, finite element reverse analysis is adopted to determine their plastic parameters. According to the gradient distributions of the elasto-plastic parameters with depth in the Mo-modified Ti, two types of mathematical expressions are proposed. Compared with the polynomial expression, the linear simplified expression does not need the graded material to be sectioned and has practical utility in the surface treatment industry. The validation of the linear simplified expression is verified by the micro-indentation test and corresponding finite element forward analysis. This approach can assist in improving the surface treatment process of the Mo-modified Ti and further enhancing its load capacity and wear resistance.

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