Dynamic Plastic Behavior Research Articles

Theoretical, experimental and numerical investigation on the behaviour of tubular shells under internal blast loading

Explosive loading of closed cylindrical structures is one of the most complicated types of high rate loadings that can be applied on fully closed structure. Considering the complexities and unknown factors that affect the dynamic-plastic behaviour of a fully closed tubular shell under internal blast loading, the main objective of this article is to achieve a better understanding of the deformation of such a structure through different theoretical, empirical and also numerical approaches. Based on some simplifying assumptions, a new pressure–time profile for the internal explosive loading of cylindrical shells whose length is shorter than its diameter would be introduced in this manuscript. Afterwards, the fundamental equations of motion would be solved by the use of the aforementioned profile so that a practical formula for the calculation of maximum radial deformation of shell would be obtained. Comparison between the theoretical values and the results of the experimental tests conducted on several pieces of aluminium shells shows that the accuracy of the new theory is approximately 82%. Furthermore, this problem will be also modelled by the use of LS-DYNA module. Considering three separate meshing zones on the explosive charge, conveying medium and also the shell body which were connected to each other on overlapping surfaces, the numerical results for the maximum transverse displacement of the shell would be obtained from the software. Comparison between the finite element method and experimental results shows an average error of around 24%.

Damage prediction of RC containment shell under impact and blast loading

There is world wide concern for safety of nuclear power installations after the terrorist attack on World Trade Center in 2001 and several other civilian structures in the last decade. The nuclear containment structure in many countries is a double shell structure (outer shell a RCC and inner a prestressed concrete). The outer reinforced concrete shell protects the inner shell and is designed for external loading like impact and blast. A comparative study of non-linear response of reinforced concrete nuclear containment cylindrical shell subjected to impact of an aircraft (Phantom) and explosion of different amounts of blast charges have been presented here. A material model which takes into account the strain rate sensitivity in dynamic loading situations, plastic and visco-plastic behavior in three dimensional stress state and cracking in tension has been developed earlier and implemented into a finite element code which has been validated with published literature. The analysis has been made using the developed software. Significant conclusions have been drawn for dissimilarity in response (deflections, stresses, cracks etc.) of the shell for impact and blast loading.

Dynamic plastic behaviour of annular plates with transverse shear effects

The dynamic response of a rigid-plastic annular plate clamped at the outer edge and free at the inner edge is considered. The plate is subjected to initial impulsive loading so that at the initial moment of time all points of the plate have the uniform transverse velocity. It is assumed that the behaviour of a rigid perfectly plastic material is controlled by a cubic yield condition and the associated flow law in the space of bending moments and the transverse shear force. Theoretical predictions are developed and compared with an upper bound solution.

Plastic response of a circular cylindrical shell to dynamic loadings

The dynamic plastic behaviour of a circular cylindrical shell subjected to an initial impulsive loading is studied. It is assumed that the thin walled tube is clamped at the left end and simply supported at the right-hand end. The behaviour of the rigid, perfectly plastic material is controlled by a cubic yield condition which retains the axial bending moment, circumferential membrane force as well as the transverse shear force. Theoretical predictions are presented for a wide range of geometrical and material parameters of the shell.

Dynamic plastic behavior of a free–free beam striking the mid-span of a clamped beam with shear and membrane effects considered

Recently Yu et al. (Int. J. Solids Struct. 38 (2001) 261) made a study on the dynamic behavior of a flying free–free beam striking the tip of a cantilever beam using the rigid, perfectly plastic (r-p-p) material model. Later, also based on the r-p-p material model Yang and Yu (Mech. Struct. Mach. 29 (2001) 391) analyzed another impact problem of a free rotating hinge beam striking a cantilever beam. Both of these studies ignored the finite deflection effects on the plastic behavior of the colliding beams. However if the free–free beam strikes a clamped beam, the influence of finite-deflections, or, geometric changes, must be retained in the governing equation if the maximum permanent transverse displacement of the clamped beam exceeds the corresponding beam thickness. The problem becomes more interesting since the deformation mechanisms of the beam system and the partitioning of energy dissipation in the beams are significantly different from those predicted by ignoring the influence of membrane forces. Accordingly the failure modes of the structure are different. In the present paper, a theoretical model based on the r-p-p material idealization is proposed to simulate the dynamic behavior when the mid-point of a translating free–free beam impinging on the mid-span of a clamped beam with the beam axes perpendicular to each other. The plastic behavior of the beam system is explored with shear sliding and finite deflection effects taken into account. The final deflection, the dissipation of energy within the two beams after impact and the influence of the structural and material parameters are discussed. It is shown that membrane force plays an important role during the response process, especially when the deflection is of the same order as the thickness of the clamped beam.

Dynamic plastic behaviour of a notched free–free beam subjected to step-loading at one end

A rigid perfectly plastic model is developed to study the initial, small deflection response of a free–free beam with an initial notch along its span under a concentrated step-loading suddenly applied at one end of the beam. Complete solutions are obtained for various combinations of the magnitude of the load, the location of the notch and its defect-severity. The partitioning of the initial energy dissipation rates is discussed for some typical situations. It is concluded that: (i) the different initial deformation mechanisms and the initial energy dissipation rate of the beam depend not only on the magnitude of the load but also on the defect-severity and location of the notch; (ii) because of the influence of the notch, the structural response of the beam is far more complicated than that of the un-notched free–free beam; and (iii) for some cases the maximum rate of energy dissipation in plastic hinges will be more than 1/3 of the total input energy rate, while for an un-notched free–free beam, it has been demonstrated that the plastic dissipated energy is always less than 1/3 of the input energy [Int. J. Impact Engng 21 (1998) 165].

Mechanical Behavior of Engineering Materials, Volume 2: Dynamic Loading and Intelligent Material Systems

11R11. Mechanical Behavior of Engineering Materials, Volume 2: Dynamic Loading and Intelligent Material Systems. - YM Haddad (Mech Eng, Univ of Ottawa, Canada). Kluwer Acad Publ, Dordrecht, Netherlands. 2000. 484 pp. ISBN 0-7923-6355-8. $225.00.Reviewed by YA Rossikhin (Dept of Theor Mech, Voronezh State Univ of Architec and Civil Eng, ul Kirova 3-75, Voronezh, 394018, Russia).The book under review is the second volume of the two-volume monograph Mechanical Behavior of Engineering Materials. This volume is devoted to the evaluation of the engineering materials properties under dynamic loading. However, due to the wide scope of topics covered and its popular presentation, this book is not a monograph, it can be classified as a tutorial on dynamic behavior of engineering materials. In each chapter, a review of well-known results in particular aspects of dynamic loading is given, which paves the way for a person inexperienced in the field for perceiving the current state of the art in the development of mechanics of materials. Having read this book, a reader will be ready to embark on in-depth study of the subject. The second volume begins with Chapter 9. The previous eight chapters, devoted to static and quasi-static loading of linear and nonlinear elastic, viscoelastic, and elastic-plastic continuum media, are contained in Volume 1 (an interested reader is referred to the review of Volume 1 by J-C Roegiers published in AMR, July 2002, p B61). Chapter 9 introduces the subject of the response of metallic materials to dynamic loading both under high and low rates. Behavior of the materials within the plastic range, with due account for plastic instability and localization effects, is reviewed in Chapter 10. Chapter 11 presents brief information concerning elastic bulk and plane wave propagation in unbounded and semi-infinite elastic media, as well as surface waves. It is worth noting that aspects of dynamic behavior of rods and plates are discussed rather weakly and superficially. Dynamic plastic behavior of engineering materials, as well as plastic shock wave propagation, are presented in Chapter 12. Linear viscoelastic properties of materials under dynamic loading are discussed in Chapter 13, and linear and nonlinear viscoelastic wave propagation is considered in Chapter 14. The dynamic behavior of fiber-reinforced composite materials is presented in Chapter 16. Chapter 17 gives an introduction into the concept of intelligence in engineering materials, as well as a review of different models, control algorithms, and analyses developed by various researchers. Pattern recognition and classification methodology for the characterization of material response states is discussed in the last chapter, 18. Each chapter ends with a list of main references, as well as the references for further reading, but this reviewer should note that only a few of them, excluding those of the author, were published during the last 10 years. Chapters 10, 11, 14, and 15 contain problems for student self-checking. Volume 2 concludes with a subject index and cumulative subject index. This reviewer can recommend Mechanical Behavior of Engineering Materials, Volume 2 only for undergraduate students of civil engineering and mechanical engineering departments as an introductory course in dynamic behavior of engineering materials.

Dynamic plastic behavior of 63 wt% Sn 37 wt% Pb eutectic solder under high strain rates

Dynamic plastic behavior of 63 wt% Sn 37 wt% Pb eutectic solder under high strain rates

DYNAMIC PLASTIC BEHAVIOR OF A FREE-ROTATING HINGED BEAM STRIKING A CANTILEVER BEAM1*

A study was made of the dynamic plastic response of two deformable beams colliding with each other. The driving beam, which was a free-rotating hinged beam with a tip mass at the free end, strikes at the tip mass of a target cantilever beam, which was stationary. Complete solutions based on the rigid, perfectly plastic material idealization were obtained for various deformation mechanisms during the dynamic response process of the two plastic beams. Typical numerical examples are presented to demonstrate [[1]] the dynamic plastic behavior of the system after collision between two rectangular beams, as well as between an Ishaped beam and a rectangular beam; and [[2]] the influence of the tip mass ratio on the plastic deformation of the driving and target beams. *Communicated by F. Ziegler.

Dynamic behavior of double cantilever beams subjected to impact

The dynamic plastic behavior of a double cantilever beam system subjected to impact by a rigid mass at their tips is studied. Three approaches are adopted: a rigid, perfectly plastic (r.p.p) complete solution, a mode solution, and an elastic, perfectly plastic (e.p.p) solution based on non-linear beam theory using the Dyna3D finite element code. In the complete solution based on the r.p.p idealization, the dynamic response of the system comprises three successive phases, which are characterized by different sets of plastic hinges in the system and expressed in closed analytical forms. The mode solution based on the r.p.p idealization is presented in a much simpler form. Particular attention is paid to the partitioning of the dissipation of the total input energy between the two beams. Numerical examples are given to demonstrate the influence of some of the structural parameters on the energy partitioning. In particular, the results obtained from the three approaches are compared, and the validity of the r.p.p models in predicting the energy partitioning between the two beams is examined.

Deformable body impact: dynamic plastic behaviour of a moving free–free beam striking the tip of a cantilever beam

A theoretical model based on the rigid, perfectly plastic material idealization is proposed to simulate the dynamic behaviour of two deformable beams colliding with each other. The mid-point of a moving free–free beam is assumed to impinge on the tip of a cantilever beam with the beam axes perpendicular to each other. Complete solutions are obtained for various deformation mechanisms during the dynamic response process for the two deformed beams, and plastic shear sliding is taken into account. Attention is focused on the partitioning of the input energy between the two deformed beams after impact. A deformation map in a governing parameter plane is constructed to permit the calculation of the energy partitioning for a range of the beams’ parameters. This consists of nine regions corresponding to various deformation mechanisms. Typical numerical results are presented to demonstrate the influence of structural and geometrical parameters such as the ratios of the fully plastic bending moments of the two beams, of their fully plastic shear forces, of their masses per unit length and their length, on the energy partitioning after impact. Finally, the severance limit is given for the case of both beams having rectangular cross-sections. This indicates that shear sliding failure may happen in either of the beams if the initial kinetic energy is sufficiently large.

Dynamic plastic behavior of circular plate usingunified yield criterion

Dynamic plastic behavior of a rigid-plastic simply supported circular plate undermoderate partial uniformly distributed impulsive load is complemented by using a unified yieldcriterion which consists of a generic of convex piecewise linear yield criteria. Upper bound andlower bound plastic responses of the plate under rectangular pulse are obtained; responsebehavior of the plate with respect to the Mises criterion is derived by a proximal manner. Theinconstant circumferential moment distribution and the non-linear flow velocity distribution in theperiods corresponding to the two motion phases are suggested in this paper. Static and kinematicadmissibility of the dynamic plastic solutions is discussed and two types of moment profiles forthe plates under intense dynamic load are supposed for studying in the future.

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

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.

Notch sensitivity of circular rings subjected to impact loading

‘Notch-sensitive regions’ have been observed during a series of experimental investigations into the dynamic plastic behaviour and failure of thin-walled metallic radially notched circular rings with arc-shaped supports subjected to concentrated impact loads. The experimental results show that the exterior notches at some regions have no effect on the deformation of the rings, but do have effect at the remaining regions. The notch-sensitive region is theoretically determined by using the equivalent structures technique; fairly good agreement has been reached between the simple theory and the experimental results. Both dimensional and theoretical analyses prove that whether a plastic hinge formed or not at the notched section does not depend on the mean radius of the ring and the input kinetic energy. It depends on the weak coefficient of the notched section and the angle of the support. Generally speaking, there are mainly three failure modes for a notched circular ring with arc-shaped support under impact loading: Mode I, large inelastic deformation when the notch is outside the sensitive region, in this case the ring deforms as a normal one; Mode II, large inelastic deformation only at some part of the ring and tearing occurred at the notched sections; mode III, large inelastic deformation and total rupture occurred at the notched sections. It is believed that the present study could assist the understanding of the dynamic behaviour and failure of other kinds of nonstraight components with macroscopic imperfections under impulsive loading.

Shear and Bending Response of a Rigid Plastic Circular Plate Struck Transversely by a Mass*

ABSTRACT A theoretical analysis is presented for the dynamic plastic behavior of a fully clamped rigid, perfectly plastic circular plate struck transversely by a rigid mass at the center. It is shown that the maximum permanent transverse deformation predicted by a theoretical solution, with combined transverse shear and bending, is similar to that from a bending-only solution when the ratio of shear strength to bending capacity υ is sufficiently large. However, when the strength parameter υ is small, the transverse shear deformation dominates the response and the maximum deformation from a combined shear and bending solution increases sharply with a decrease in υ. It is also found that the transverse shear deformation becomes more important with an increase in the dimensionless mass ratio β and is sensitive to the dimensionless radius ρ0 of the impact area.

LITERATURE REVIEW analysis of the shock and vibration literature: Recent Progress in the Dynamic Plastic Behavior of Structures Part Vi

LITERATURE REVIEW analysis of the shock and vibration literature: Recent Progress in the Dynamic Plastic Behavior of Structures Part Vi

The dynamic plastic behavior of a simply supported circular plate in a damping medium with finite-deflections

A theoretical analysis is presented for the dynamic plastic behavior of a simply supported rigid, perfectly plastic circular plate in damping medium with finite-deflections subjected to a rectangular pressure pulse. Analytical solutions of every moving stage under both medium and high loads are developed.

Dynamic Damage in Certain Monolithic Ceramic Materials

In the present work, the propagation of elasto-damage longitudinal stress waves in thin rods is investigated. The material behavior is characteristic to that of certain monolithic ceramics. The damage constitutive relation that characterizes this type of materials gives rise to certain dynamic behavior which is somewhat different from dynamic plastic behavior. Plastic and damage dynamic response are compared through an example.

FEATURE ARTICLE: items of special interest, tutorials, and surveys: Recent Progress in the Dynamic Plastic Behavior of Structures, Part V

FEATURE ARTICLE: items of special interest, tutorials, and surveys: Recent Progress in the Dynamic Plastic Behavior of Structures, Part V

Recent Studies on the Dynamic Plastic Behavior of Structures

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.