Recent Studies on the Dynamic Plastic Behavior of Structures

1989 ◽  
Vol 42 (4) ◽  
pp. 95-115 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Brittle Fracture ◽  
Dynamic Loads ◽  
Large Impact ◽  
Plastic Behavior ◽  
Impact Loads ◽  
Plastic Strains ◽  
Review Of The Literature ◽  
Rigid Plastic ◽  
Plastic Buckling ◽  
Fracture Transition

This article contains a review of the literature, which has been published recently, on the dynamic plastic behavior of simple structures. The dynamic loads cause large plastic strains which dominate material elastic effects. Thus, the accuracy of various refinements of simple rigid-plastic methods are discussed, together with the phenomena of pseudoshakedown under repeated loads, dynamic plastic buckling, and dynamic progressive buckling. Recent studies are also reported on similitude under large impact loads, and on the ductile-brittle fracture transition due to the changes in the physical dimensions of a structure.

Recent Studies on the Dynamic Plastic Behavior of Structures - An Update

1996 ◽  
Vol 49 (10S) ◽  
pp. S112-S117 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Air Transportation ◽  
Transportation Systems ◽  
Dynamic Loads ◽  
Plastic Behavior ◽  
Structural Members ◽  
Applied Mechanics ◽  
Review Of The Literature ◽  
Plastic Response ◽  
Energy Absorbing ◽  
Inelastic Strains

This article contains a brief review of the literature, published since the previous Applied Mechanics Reviews article in 1989 [1], on the dynamic plastic response of basic structural members made from ductile metallic type materials. The external dynamic loads cause large inelastic strains in the structural members which dominate material elastic effects. Thus, the external dynamic energy is absorbed plastically and, generally speaking, produces large permanent deformations. This field of research is of interest for the structural crashworthiness and collision protection of land, sea and air transportation systems, as well as the design of energy absorbing systems, and provides vital input into safety calculations and hazard assessments throughout industry.

Some Recent Studies on Plastic Behavior of Plates Subjected to Large Impact Loads

2002 ◽  
Vol 124 (3) ◽  
pp. 125-131 ◽  
Author(s):  
Ge Wang
Keyword(s):  
Steel Plates ◽  
Large Impact ◽  
Plastic Behavior ◽  
Complex Object ◽  
Impact Loads ◽  
Complex Interactions ◽  
Analytical Formulas ◽  
Membrane Stretching ◽  
The Many ◽  
Deformation Patterns

This paper reviews some recent studies on the plastic behavior of steel plates subjected to large impact loads. This is an important topic for risk assessments and safety evaluations because of the ever heightened public concern about safety of marine structures and potential harm to the environment due to marine accidents. Emphasis is given to the complex plastic deformation patterns recently identified, including plate punching, plate tearing, and local denting of web girders. Descriptions are given of the complex interactions of the many mechanisms involved in these deformation patterns, including membrane stretching, local plastic bending, complex object geometry, rupture, cracking and friction. Advanced analytical formulas that can be used to describe these behavior mechanisms are introduced. These formulas are based on the advanced structural crashworthiness methodology.

Prediction of the Absence of Brittle Failure Risk for Ferritic Steel Piping Components in the Brittle-Ductile Region

2011 ◽  
Author(s):  
S. Marie ◽  
J. Schwab ◽  
S. Vidard
Keyword(s):  
Brittle Fracture ◽  
Fracture Risk ◽  
Brittle Failure ◽  
Risk Evaluation ◽  
Critical Stress ◽  
Ferritic Steel ◽  
Loading Condition ◽  
Maximum Principal Stress ◽  
Fracture Transition ◽  
Secondary Loop

This paper deals with the brittle fracture risk evaluation for a C-Mn piping component in the upper shelf of the brittle to ductile fracture transition temperature range, with the main objective to validate a predictive criteria, able to demonstrate the complete absence of brittle fracture risk. The criteria is based one a critical stress and the volume around the crack were the maximum principal stress exceed this critical stress. The model is calibrated on notched tensile specimens and CT specimens. A four-points bending pipe test has then been designed using this criterion to insure that no brittle fracture will occurs at a temperature that all CT specimens failed by cleavage. The material is a French secondary loop Tu42C ferritic steel and the pipe dimensions for the test are the same than the size of the principal secondary loop pipes. The results of the pipe test confirm the prediction with the model and the interpretation lead to define an equivalence between the loading conditions (based on the J parameter) of the pipe and the loading condition of a CT specimen.

scholarly journals Investigating the Pre-Damaged PZT Sensors under Impact Traction

2018 ◽  
Vol 6 (4) ◽  
pp. 142 ◽  
Author(s):  
Sakineh Fotouhi ◽  
Mohamad Fotouhi ◽  
Ana Pavlovic ◽  
Nenad Djordjevic
Keyword(s):  
Sandwich Panel ◽  
Piezoelectric Sensors ◽  
Dynamic Loads ◽  
Impact Loads ◽  
Elastic Plates ◽  
Factors Affecting ◽  
Reliable Performance ◽  
Vibration Impact ◽  
Static And Dynamic Loads ◽  
Marine Applications

Ships are usually under vibration, impact, and other kinds of static and dynamic loads. These loads arise from water flow across the hull or surfaces, the propeller cavitation, and so on. For optimal design purposes and reliable performance, experimental measurements are necessary. These sensors are often used under or near the water, working conditions that improve the risk of sensor damage. This paper aims at investigating, by the use of finite elements, the behavior of damaged piezoelectric sensors under traction and impact loads. The numerical method was calibrated using results available in the literature regarding piezoelectric and elastic plates with a central crack. After calibration, the simulation was used on two types of Lead-Zirconium-Titanium oxide (PZT) sandwich panel structures reinforced by aluminum skins. The results proved that the damage size and impact energy are important factors affecting the response of piezoelectric sensors; therefore, special attention might be considered when using these sensors for marine applications.

On the Mechanics of Micro-Thin Foil Production

1973 ◽  
Vol 95 (3) ◽  
pp. 803-808 ◽  
Author(s):  
E. G. Thomsen ◽  
H. H. Thomsen
Keyword(s):  
Thin Foil ◽  
Large Impact ◽  
Interfacial Friction ◽  
Impact Loads ◽  
Metal Foil ◽  
Poisson Effect ◽  
Compression Process ◽  
Leaf Production ◽  
Actual Mechanism ◽  
Stretching Process

The mechanics of micro-thin foil or leaf production by hammering has been analyzed. It was found that the metal foil cannot be reduced by a compression process alone because of the large impact loads that would be required, due to interfacial friction between the foil and the separating paper sheets. It is demonstrated that a likely mechanism is a plastic stretching process of the metal combined with relatively large elastic stretching of the paper due to the Poisson effect when a blow is struck. The actual mechanism is probably a combination of stretching and slipping of the metal.

A Direct Design Procedure for FPSO Side Structures Against Large Impact Loads

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Lin Hong ◽  
Jørgen Amdahl ◽  
Ge Wang
Keyword(s):  
Heavy Traffic ◽  
Limit State ◽  
Design Procedure ◽  
Large Impact ◽  
Collapse Mechanism ◽  
Impact Loads ◽  
Element Analysis ◽  
Direct Design ◽  
Offshore Industry ◽  
The Impact

The performance and consequence of FPSOs subjected to large impact loads such as collisions from supply vessels or merchant vessels are of great concern in the offshore industry, notably when they are located close to heavy traffic lanes. Due to the lack of operation experience for ship-shaped FPSOs, direct design procedures are needed to rationalize the structural design of FPSOs, which can mitigate the consequence of collision accident and avoid possible contaminated compartment flooding. In this paper, three collision scenarios between a FPSO and a bulbous supply vessel are analyzed through explicit nonlinear finite element analysis code LS-DYNA. Thereafter, a direct design procedure is proposed for ship-shaped FPSO side structure against accidental collision forces, which follows the principle of accidental limit state. The procedure comprises the determination of the impact forces, shell plating, and stiffener framing design, and the consideration of the acceptance criterion. The proposed method is especially useful in the preliminary design phase because the design procedure for plating and stiffener is based on analytical formulas derived from plastic method and appropriate collapse mechanism. The side structure decided by the proposed design procedure also complies with the strength design principle that has been adopted in NORSOK standard. The proposed approach is demonstrated by the design of the FPSO side structure against impact loads from a 7500 tons supply vessel and verified by means of integrated collision analysis. The procedure could also be served to estimate the damage due to accidental loads.

Rigid-plastic analysis of floating ice sheets under impact loads

1981 ◽  
Vol 8 (4) ◽  
pp. 409-415
Author(s):  
John B. Kennedy ◽  
K. J. Iyengar
Keyword(s):  
Impact Load ◽  
Design Method ◽  
Yield Criterion ◽  
Ice Sheets ◽  
Contact Radius ◽  
Impact Loads ◽  
Rigid Plastic ◽  
Deformation Response ◽  
Safe Thickness ◽  
The Impact

The deformation response of floating ice sheets under high intensity, short duration loads is examined. Using a rigid-plastic theory, together with a Tresca yield criterion, expressions are derived for the total time of response and the final deformed configuration of floating ice sheets. The influence of the magnitude of the impact load and the load-contact radius on the various design quantities such as deflection profile and stress distribution is discussed. Based on the results derived, a design method is presented to find the safe thickness of a floating ice sheet to sustain a given impact load. The method is illustrated with a numerical example.

The Influence of Large Deflections on the Behavior of Rigid-Plastic Cylindrical Shells Loaded Impulsively

1970 ◽  
Vol 37 (2) ◽  
pp. 416-425 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Cylindrical Shells ◽  
Dynamic Loads ◽  
Large Deflections ◽  
Finite Deflections ◽  
Shell Material ◽  
Governing Equations ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Dynamic Analyses ◽  
Circular Cylindrical Shells

A theoretical investigation is herein undertaken in order to examine the response of circular cylindrical shells subjected to dynamic loads of an intensity sufficient to cause large permanent deformations. The shell material is assumed to be rigid, perfectly plastic and the influence of finite deflections is retained in the governing equations. It emerges clearly from the study that geometry changes influence markedly the shell behavior even for quite small deflections and, therefore, they should be retained in any dynamic analyses of cylindrical shells with axial restraints.

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