Response and Failure of Ductile Circular Plates Struck by a Mass

1997 ◽  
Vol 119 (3) ◽  
pp. 332-342 ◽  
Author(s):  
N. Jones ◽  
S.-B. Kim ◽  
Q. M. Li
Keyword(s):  
Theoretical Analysis ◽  
Mild Steel ◽  
Aluminium Alloy ◽  
Reasonable Agreement ◽  
Failure Mechanisms ◽  
Experimental Studies ◽  
Experimental Results ◽  
Steel Plates ◽  
Circular Plates ◽  
Plastic Response

A theoretical analysis is presented in this paper to predict the dynamic plastic response of aluminium alloy and mild steel circular plates when struck normally by blunt solid cylindrical masses at the center. Reasonable agreement is obtained with experimental results for the permanent transverse displacements. Different failure mechanisms, which have been found in previous experimental studies on aluminium alloy and mild steel plates, are also illustrated by the proposed theory.

A Rudimentary Analysis of Improving Fatigue Life of Metals by Shot-Peening

1990 ◽  
Vol 57 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Y. F. Al-Obaid
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Theoretical Analysis ◽  
Shot Peening ◽  
Reasonable Agreement ◽  
Experimental Results ◽  
Single Shot ◽  
Repeated Impact ◽  
Entire Surface ◽  
Complicated Process

In this paper, a rudimentary analysis of improving fatigue life of metals is presented. The process is viewed as one of repeated impact of a stream of hard shots on to a target. The model considers first a single shot impinging upon a target and, on bouncing, it leaves a residual stress below the surface of the target. The problem is then generalized to consider the effect of a stream of shots by assuming their effect to be uniformly distributed over the entire surface. The analysis is highly simplified and it mainly aims at understanding the mechanics of this complicated process. Although rudimentary, the theoretical analysis is seen to be in reasonable agreement with experimental results performed with shots on targets of various materials.

The Effect of Inclined Loads on the Large Deflection Behaviour of Elastoplastic Work-Hardening Straight and Pre-Bent Cantilevers

1995 ◽  
Vol 209 (2) ◽  
pp. 87-96 ◽  
Author(s):  
J H Liu ◽  
A G Atkins ◽  
A J Pretlove
Keyword(s):  
Elastic Modulus ◽  
Theoretical Analysis ◽  
Work Hardening ◽  
Reasonable Agreement ◽  
Large Deflection ◽  
Plastic Region ◽  
Experimental Results ◽  
Modulus Ratio ◽  
Inclined Loads

A theoretical analysis is presented to examine the effect of inclined tip load on the large deflection behaviour of an elastoplastic cantilever with linear work hardening. The cantilever is either initially straight or pre-bent to a tip angle of ø (see Fig. 1). When the load is large enough, the overall deformation of a pre-bent cantilever is smaller than that of an initially straight one as a result of the influence of the guided end. The maximum plastic region spm in the cantilever increases with the force angle ø and the plastic-elastic modulus ratio α, but decreases as the beam flexibility parameter β increases. Some unstable deformation may occur in the initially straight cantilever when ø > π/2 and this depends on the value of α and β. Reasonable agreement is obtained between the theoretical analysis and experimental results.

The Effect of Joints on the Transverse Vibration of a Simple Structure

1990 ◽  
Vol 204 (1) ◽  
pp. 37-42 ◽  
Author(s):  
F P E Dunne ◽  
M Heppenstall
Keyword(s):  
Mild Steel ◽  
Compressive Stress ◽  
Transverse Vibration ◽  
Reasonable Agreement ◽  
Simple Structure ◽  
Natural Frequencies ◽  
Theoretical Models ◽  
Experimental Results ◽  
Predicted Values ◽  
Vibration Tests

Transverse vibration tests were carried out on a cold-drawn mild steel tubular beam containing annular metal-to-metal joints. The tests were also carried out on an unjointed beam of the same dimensions. An axial compressive preload was applied giving a compressive stress in the range of 0–80 N/mm2. Joints between rough turned surfaces, between ground surfaces and mixed joints between both types of surface were used. Dynamic bending stiffnesses of the joints over the range of compressive stress were determined. Stiffness of the turned and mixed joints was found to be proportional to preload. Stiffness of ground joints increased with preload, but not proportionally. Theoretical models were developed to determine joint bending siffness and natural frequencies of transverse vibration of the jointed beams. Predicted values of joint bending stiffness for ground and turned joints were in reasonable agreement with the experimental results.

A Study on the Large Ductile Deformations and Perforation of Mild Steel Plates Struck by a Mass—Part I: Experimental Results

1997 ◽  
Vol 119 (2) ◽  
pp. 178-184 ◽  
Author(s):  
N. Jones ◽  
S.-B. Kim
Keyword(s):  
Mild Steel ◽  
Empirical Equation ◽  
Longitudinal Axis ◽  
Experimental Results ◽  
Steel Plates ◽  
Ductile Deformation ◽  
Circular Boundary ◽  
Mass Part ◽  
The Impact ◽  
Made In

An experimental study is reported on the ductile deformation and perforation of plates struck at the center by solid cylindrical projectiles having the longitudinal axis normal to the plate surface. The plates, which are made from 4 to 8-mm-thick mild steel sheet, are fully clamped around a circular boundary and are struck by projectiles having blunt ends and traveling with impact velocities within the range 7.7–118.9 m/s. Comparisons are made in Part II with the static perforation behavior and with previously published experimental results and several empirical equations for the impact case. A new empirical equation, which retains the influence of the impact velocity on the perforation energy, is also proposed in Part II.

New dimensionless numbers for deformation of circular mild steel plates with large strains as a result of localized and uniform impulsive loading

2016 ◽  
Vol 234 (2) ◽  
pp. 231-245
Author(s):  
Hashem Babaei ◽  
Tohid Mirzababaie Mostofi
Keyword(s):  
Mild Steel ◽  
Empirical Analysis ◽  
Impulsive Loading ◽  
Empirical Models ◽  
The Other ◽  
Steel Plates ◽  
Dimensionless Number ◽  
Circular Plates ◽  
Dimensionless Numbers ◽  
Decomposition Procedure

This study introduces an empirical analysis approach to assess mechanical behavior of thin circular mild steel plates subjected to uniform and localized impulsive loading. The empirical models have been derived by singular values decomposition procedure to predict midpoint deflection of circular plates. The essence of empirical analysis is based on dimensionless numbers. For this, Jones’s dimensionless number λ is considered as a dimensionless number for both uniform and localized loading. This number has some features such as considering plate geometries, mechanical properties of material, and loading conditions. The well-known Cowper–Symonds constitutive equation has been used to investigate the potential influence of material strain rate sensitivity where the constant parameters in this equation are considered as a function of plate thickness. In localized impulsive loading, two other dimensionless numbers are appended to investigate the effects of changing load ratio and standoff distance. The results of empirical models are compared to the other experimental and theoretical studies which have been performed by different researchers. Also, the obtained results show that the presented models have much less root mean square error than the other ones. Hence, these models are suitable to predict midpoint deflection of thin circular plates subjected to both uniform and localized impulsive loading.

On dimensionless numbers for the dynamic plastic response of quadrangular mild steel plates subjected to localized and uniform impulsive loading

2016 ◽  
Vol 231 (5) ◽  
pp. 939-950 ◽  
Author(s):  
Hashem Babaei ◽  
Tohid Mirzababaie Mostofi ◽  
Ehsan Armoudli
Keyword(s):  
Mild Steel ◽  
Rate Sensitivity ◽  
Impulsive Loading ◽  
The Other ◽  
Steel Plates ◽  
Maximum Deflection ◽  
Plastic Response ◽  
Effective Parameters ◽  
Dimensionless Numbers ◽  
Singular Value Decomposition Method

This paper studies the dynamic plastic response of thin quadrangular mild steel plates subjected to uniform and localized impulsive loading. For this, two new dimensionless numbers based on dimensionless governing equation of plates have been suggested. Four different effective parameters such as plate geometry, inertia of applied load, mechanical properties of material and strain rate sensitivity have been considered in suggested dimensionless numbers. The unknown coefficients of these numbers have been calculated by using singular value decomposition method. In order to illustrate the ability of empirical constitutive equations for predicting the maximum deflection, these equations are compared with different sets of experimental results that have been performed by various researchers. The comparison between the results of present empirical equations and the other theoretical and experimental ones shows that these models are more accurate than the other ones and are suitable to use for predicting the maximum deflection of all quadrangular mild steel plates subjected to uniform and localized loading.

On the Scaling of Low-Velocity Perforation of Mild Steel Plates

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Norman Jones ◽  
R. S. Birch
Keyword(s):  
Mild Steel ◽  
Scaling Laws ◽  
Experimental Results ◽  
Steel Plates ◽  
Ductile Deformation ◽  
Low Velocity ◽  
Rigid Plastic ◽  
Scale Range ◽  
Simple Equations ◽  
The Impact

Experimental results are reported for the perforation of geometrically similar fully clamped circular and square mild steel plates struck transversely by cylindrical projectiles having blunt, conical, and hemispherical noses. The striking masses are much heavier than the corresponding plate mass and travel with initial impact velocities up to about 12m∕s. The blunt projectiles perforate the plating easiest, while the hemispherical-nosed ones require the greatest energy. The perforation energy of a conical-nosed projectile is somewhat less than that for a hemispherical-nosed one. The data are used to explore the validity of the geometrically similar scaling laws over a geometric scale range of 4. The experimental results are compared to the empirical equations for the impact perforation of plates and with theoretical rigid-plastic predictions for the large ductile deformation behavior of those test specimens, which did not suffer cracking or perforation. The experimental results satisfy the requirements of geometrically similar scaling and some simple equations are presented, which are useful for design purposes.

Viscoelastic Boundary Damping of Beams and Plates

1964 ◽  
Vol 31 (1) ◽  
pp. 61-71 ◽  
Author(s):  
T. J. Mentel
Keyword(s):  
Energy Dissipation ◽  
Theoretical Analysis ◽  
Experimental Results ◽  
Elementary Level ◽  
Circular Plates ◽  
Principal Characteristics ◽  
Boundary Damping ◽  
Series Of Experiments

A series of experiments on boundary, damped beams are described which identify separately the effectiveness of axial and transverse motions of the embedded beam ends in producing energy dissipation. A comparatively elementary level of theoretical analysis is shown to be adequate in explaining most of the experimental results. A subsequent series of experiments is then described which tests the damping effectiveness of a small inset of viscoelastic adhesive at the supports of beams and plates, the inset design being motivated by the results of the first experiments. The principal characteristics of the inset design are determined experimentally and a supporting theory (for beams and circular plates) is outlined.

Paradoxes of Falsification

1996 ◽  
Vol 49 (2) ◽  
pp. 447-462 ◽  
Author(s):  
Fenna H. Poletiek
Keyword(s):  
Cognitive Psychology ◽  
Theoretical Analysis ◽  
Hypothesis Testing ◽  
Experimental Studies ◽  
Experimental Results ◽  
Testing Strategy ◽  
Confirmatory Testing ◽  
Empirical Results ◽  
Normative Principle

This paper deals with the concept of falsification in hypothesis testing research. A theoretical analysis of assumptions about falsifying behaviour and hypothesis-falsifying observations is presented, with two experimental studies. Both the theoretical analysis and the experimental results point to a number of paradoxes underlying the normative principle of falsification in cognitive psychology. First, subjects experience the falsificatory testing strategy as an impossible strategy to conduct. Obtaining falsifying results is a consequence of the quality of the hypothesis rather than of specific testing behaviour (Experiment 1 and Experiment 2). Second, under some conditions falsifying results impede rather than facilitate discovery (Experiment 2). Confirmatory testing and falsificatory testing, which have been the crucial concepts in the study of hypothesis-testing behaviour, may actually be questionable approaches to testing behaviour. The theoretical analysis is related to the standard analyses of Popper (1963) and Klayman and Ha (1987). The empirical results are discussed in relation to previous studies on falsificatory testing behaviour.

Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

2020 ◽  
pp. 17-24
Keyword(s):  
Welded Joint ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Tensile Tests ◽  
Physical Nonlinearity ◽  
Steel Plates ◽  
Optimal Parameters ◽  
Actual Problem ◽  
Numerical Research ◽  
Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

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