Impact Force of a Rigid-Plastic Missile

1984 ◽  
Vol 51 (1) ◽  
pp. 102-106 ◽  
Author(s):  
M. P. White
Keyword(s):  
Critical Velocity ◽  
Contact Force ◽  
Impact Force ◽  
Plastic Material ◽  
The Other ◽  
Rigid Plastic ◽  
Impact Process ◽  
Rigid Plastic Material ◽  
Time Variations ◽  
The Impact

A cylindrical missile, assumed to be of a rigid-plastic material strikes a nonyielding target normally and end-on. Above a certain (critical) velocity the nose of the missile disintegrates or spatters, and below that velocity the nose flattens to a mushroom form. The contact force decreases with decreasing velocity during impact but experiences a jump as the critical velocity is passed during slowdown. This paper gives a method of calculating the critical velocity and the contact force as function of time, as well as the time variations of the other parameters of the impact process.

The permanent deformation of a cantilever struck transversely at its tip

1955 ◽  
Vol 228 (1175) ◽  
pp. 462-476 ◽  
Keyword(s):  
Plastic Material ◽  
Permanent Deformation ◽  
Rigid Plastic ◽  
Accurate Definition ◽  
Special Cases ◽  
Rigid Plastic Material ◽  
The One ◽  
Definition Of ◽  
Falling Weight ◽  
The Impact

An analysis is given for the deformation of a cantilever made from a rigid-plastic material struck transversely at its tip by a moving mass. Two special cases are found to be of interest: mass of striker large, and mass of striker small. Experiments were carried out on model mildsteel cantilevers under these two extreme conditions: in the one case the striker was a falling weight, in the other a rifle bullet. The theoretical and experimental results are compared, and it is shown that there is good agreement at points remote from the impact, but that prediction of local damage depends on accurate definition of the conditions of striking.

Stamping Rectangular Plates into Doubly-Curved Dies

1984 ◽  
Vol 198 (2) ◽  
pp. 109-125 ◽  
Author(s):  
T X Yu ◽  
W Johnson ◽  
W J Stronge
Keyword(s):  
Plastic Material ◽  
Rectangular Plates ◽  
Rigid Plastic ◽  
Punch Force ◽  
Plate Buckling ◽  
Rigid Plastic Material ◽  
Force Contact ◽  
Curvature Distribution ◽  
Doubly Curved ◽  
Deformation Modes

Shallow spheroidal shell segments have been press formed from rectangular plates by stamping between a die and matching punch that have two degrees of curvature. Experiments on mild steel, copper and aluminium plates that were not clamped in the die have measured the punch force, contact regions and final curvature distribution; and have observed plate buckling for a range of die curvature ratios and plate sizes. An analysis based on a rigid/plastic material idealization and decoupled in-plane forces and bending moments has been correlated with these experiments. The sequence of deformation modes has been identified; initially these are bending but in later stages, in-plane forces predominate.

ANALYSIS OF ELASTIC IMPACT ON THIN SHELL STRUCTURES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1349-1354 ◽  
Author(s):  
SHIUH-CHUAN HER ◽  
CHING-CHUAN LIAO
Keyword(s):  
Differential Equation ◽  
Contact Force ◽  
Thin Shell ◽  
Time History ◽  
Dynamic Responses ◽  
Low Velocity Impact ◽  
Integro Differential Equation ◽  
Impact Process ◽  
Non Linear ◽  
The Impact

In this paper, a solution method for the response of a thin shell structure subjected to low velocity impact by a sphere is presented. The governing equation of the impact process is obtained by simultaneously solving the equations of motions for the sphere and shell. The derivation is based on the explicit expression of the displacement of the mid-surface of the shell under a single impulse load acting normal to apex of the shell. Incorporating the theory of convolution and Hertz contact law, a non-linear integro-differential equation in terms of the indentation of the contact, for the impact process is derived. The non-linear integro-differential equation is solved by the numerical scheme of Runge-Kutta method to obtain the time history of the contact force at the impact point of the shell. The contact force is then applied on the apex of the shell, the dynamic responses of the shell including the displacement and stress are obtained by the finite element method. The results are validated with the experimental test and numerical calculation published in the literatures. The effects of the radius and velocity of the impactor on the impact response is investigated through parametric study.

Compliant Impact Generator for Required Impact and Contact Force

2008 ◽  
Author(s):  
Burak Demirel ◽  
Mu¨min Tolga Emirler ◽  
Ahmet Yo¨ru¨kog˘lu ◽  
Nebahat Koca ◽  
U¨mit So¨nmez
Keyword(s):  
Contact Force ◽  
Impact Force ◽  
Flexible Beam ◽  
Crank Angle ◽  
Length Width ◽  
Force Impact ◽  
Force Generator ◽  
The Impact ◽  
Maximum Contact ◽  
Novel Design

A novel design of compliant slider crank mechanism is introduced and utilized as an impact force generator and contact force generator. This class of compliant slider mechanisms incorporates an elastic coupler which is an initially straight flexible beam and buckles when it hits the stopper. The elastic pin-pin coupler (a buckling beam) behaves as a rigid body prior to the impact pushing the rigid slider. At a certain crank angle the slider hits a stopper generating an impact force. Impact force can be changed by changing the angular velocity of the crank, therefore; achieving a desired velocity of the slider. Moreover, after the impact when the vibrations die out the maximum contact force can also be predetermined by designing the coupler dimensions (length, width, thickness and the amount of compression). Contact duration (crank angle) can also be changed and adjusted in this mechanism by changing the adjustable location of the impacted object.

Theory of compression of a compressible rigid-plastic material

1974 ◽  
Vol 10 (3) ◽  
pp. 323-326
Author(s):  
I. S. Degtyarev ◽  
V. L. Kolgomorov
Keyword(s):  
Plastic Material ◽  
Rigid Plastic ◽  
Rigid Plastic Material

Response of a Rigid-Plastic Ring to Impulse Loading

1967 ◽  
Vol 34 (2) ◽  
pp. 329-336 ◽  
Author(s):  
G. B. Cline ◽  
W. E. Jahsman
Keyword(s):  
Incident Energy ◽  
Plastic Material ◽  
Maximum Magnitude ◽  
Impulse Loading ◽  
Rigid Plastic ◽  
Plastic Ring ◽  
Stress Mode ◽  
Rigid Plastic Material ◽  
Impulse Load ◽  
Final Deformation

Formulas are derived which describe the dynamic response of a ring of rigid-plastic material which is subjected to an arbitrarily distributed impulse load. When the impulse is distributed over half the ring in a cosine fashion, the final deformation is proportional to the square of the maximum magnitude of the applied impulse. Although the predominant deformation is in a bending or “ovaling” mode, one half of the incident energy is dissipated in the “membrane” or direct stress mode. The remainder is divided equally between bending (plastic work at the hinges) and kinetic energy.

Rigid-Plastic Meshfree Method for Metal Forming Simulation

2003 ◽  
Author(s):  
Young H. Park
Keyword(s):  
Metal Forming ◽  
Plastic Material ◽  
Meshfree Method ◽  
Large Plastic Deformation ◽  
Rigid Plastic ◽  
Mesh Distortion ◽  
Forming Simulation ◽  
Rigid Plastic Material ◽  
Plastic Analysis ◽  
Main Variable

In this paper, material processing simulation is carried out using a meshfree method. With the use of a meshfree method, the domain of the workpiece is discretized by a set of particles without using a structured mesh to avoid mesh distortion difficulties which occurred during the course of large plastic deformation. The proposed meshfree method is formulated for rigid-plastic material. This approach uses the flow formulation based on the assumption that elastic effects are insignificant in the metal forming operation. In the rigid-plastic analysis, the main variable of the problem becomes flow velocity rather than displacement. A numerical example is solved to validate the proposed method.

Pressbrake Bending in the Punch-Sheet Contact Region—Part 1: Modeling Nonuniformities

1988 ◽  
Vol 110 (2) ◽  
pp. 124-130 ◽  
Author(s):  
F. Pourboghrat ◽  
K. A. Stelson
Keyword(s):  
Shear Stress ◽  
Simple Model ◽  
Stress Distribution ◽  
Plastic Material ◽  
Contact Region ◽  
Rigid Plastic ◽  
Material Models ◽  
Rigid Plastic Material

A simple model of pressbrake bending in the punch-sheet contact region is presented. The pressure and shear stress at the punch-sheet interface cause the stress distribution in the sheet to change as a function of angle. In Part 1 of this paper, a model to predict nonuniformities as a function of the geometry and the frictional conditions is presented. In Part 2, the model will be used to predict the formation of a gap between the sheet and the punch. Elastic and rigid-plastic material models of the sheet are considered, and are shown to produce remarkably similar results.

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