Analytical Solution for Pin-Supported Metal Foam Core Sandwich Beam with Local Denting

2011 ◽  
Vol 462-463 ◽  
pp. 639-644
Author(s):  
Qing Hua Qin ◽  
Jian Xun Zhang ◽  
Tao Wang ◽  
Tie Jun Wang
Keyword(s):  
Carrying Capacity ◽  
Metal Foam ◽  
Sandwich Beam ◽  
Structural Response ◽  
Metallic Foam ◽  
Foam Core ◽  
Load Carrying Capacity ◽  
Rigid Plastic ◽  
Load Carrying ◽  
Axial Stretching

Structural response of pin-supported metallic foam core sandwich beam is theoretically investigated. Effects of local denting and core strength and interaction of bending and axial stretching are considered in analysis. A rigid-plastic beam-on-foundation is employed to consider local denting deformation. The local denting continues during the overall deformation of sandwich beam. It is shown that upon neglecting the effect of local denting, the load-carrying capacity and energy absorption of sandwich beam may be overestimated, and the normal axial (membrane) force associated with plastic stretching substantially stiffens the sandwich beams.

A Yield Criterion for Hybrid Asymmetric Metal Sandwich Structures and its Application

2016 ◽  
Vol 08 (01) ◽  
pp. 1650001 ◽  
Author(s):  
Chao Yuan ◽  
Qinghua Qin ◽  
T. J. Wang
Keyword(s):  
Carrying Capacity ◽  
Yield Criterion ◽  
Sandwich Beam ◽  
Large Deflections ◽  
Load Carrying Capacity ◽  
Flat Punch ◽  
Element Analysis ◽  
Load Carrying ◽  
Axial Stretching ◽  
Good Agreement

In this paper, a yield criterion for hybrid asymmetric metal sandwich structure is proposed including the combined effects of geometrical and physical asymmetries. Taking account of the interaction of bending and axial stretching and using the yield criterion, we obtain an analytical solution for large deflections of fully clamped hybrid asymmetric sandwich beam transversely loaded by a flat punch at mid-span. Moreover, finite element analysis is performed and good agreement is achieved between numerical results and analytical predictions. It is shown that the well-designed hybrid asymmetric sandwich beam may have higher load-carrying capacity than the conventional geometrically or physically asymmetric counterpart in large deflections.

Large Deflection of a Pin-Supported Slender Geometrically Asymmetric Sandwich Beam under Transverse Loading

2013 ◽  
Vol 535-536 ◽  
pp. 405-408
Author(s):  
Jian Xun Zhang ◽  
Qing Hua Qin ◽  
Wei Long Ai ◽  
Zheng Jin Wang ◽  
Tie Jun Wang
Keyword(s):  
Sandwich Structure ◽  
Large Deflection ◽  
Metal Foam ◽  
Yield Criterion ◽  
Sandwich Beam ◽  
Structural Response ◽  
Foam Core ◽  
Transverse Loading ◽  
Flat Punch ◽  
Axial Stretching

The objective of this work is to study the large deflection of a pin-supported slender geometrically asymmetric metal foam core sandwich beam under transverse loading by a flat punch. Based on the yield criterion for geometrically asymmetric metal foam core sandwich structure, analytical solution for the large deflection of a pin-supported slender sandwich beam is obtained, in which the interaction of bending and stretching induced by large deflection is considered. The finite element results confirm the accuracy of the analytical solutions. The effects of asymmetric factor and boundary condition on the structural response of the asymmetric sandwich beam are discussed in detail. It is shown that the axial stretching induced by large deflection plays an important role in the load-carrying and energy absorption capacities of geometrically asymmetric sandwich structure.

LOAD-CARRYING CAPACITIES FOR CIRCULAR METAL FOAM CORE SANDWICH PANELS AT LARGE DEFLECTION

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6218-6223 ◽  
Author(s):  
W. HOU ◽  
Z. WANG ◽  
L. ZHAO ◽  
G. LU ◽  
D. SHU
Keyword(s):  
Finite Element ◽  
Velocity Field ◽  
Large Deflection ◽  
Metal Foam ◽  
Yield Criterion ◽  
Metallic Foam ◽  
Foam Core ◽  
Element Simulation ◽  
Load Carrying ◽  
Good Agreement

This paper is concerned with the load-carrying capacities of a circular sandwich panel with metallic foam core subjected to quasi-static pressure loading. The analysis is performed with a newly developed yield criterion for the sandwich cross section. The large deflection response is estimated by assuming a velocity field, which is defined based on the initial velocity field and the boundary condition. A finite element simulation has been performed to validate the analytical solution for the simply supported cases. Good agreement is found between the theoretical and finite element predictions for the load-deflection response.

Experimental investigations on the sandwich composite beams and panels with elastomeric foam core

2017 ◽  
Vol 21 (3) ◽  
pp. 865-894 ◽  
Author(s):  
AR Nazari ◽  
H Hosseini-Toudeshky ◽  
MZ Kabir
Keyword(s):  
Carrying Capacity ◽  
Sandwich Structures ◽  
Failure Mechanisms ◽  
Composite Beams ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Beams ◽  
Load Carrying Capacity ◽  
The Core ◽  
Load Carrying

In this paper, the load-carrying capacity and failure mechanisms of sandwich beams and panels with elastomeric foam core and composite laminate face sheets are investigated. For this purpose, the flexural behavior of laminated composite beams and panels (applied as face sheets) is firstly investigated under three-point bending and central concentrated loads, respectively. Then, the same examination is conducted for the sandwich beams and panels, in which the proposed elastomeric foam is utilized as the core material. It is shown that the failure mechanisms which are associated to the core in the sandwich structures with crushable foams are not considered in the examined sandwich structures. The collapse of the sandwich specimens, examined here, is observed due to the failure of the skins in some steps. By multi-step collapse of these specimens via separately failure of the top and bottom skins, a considerable amount of energy is absorbed between these steps. Due to non-brittle behavior of the core material under loading, a large compression resistance is observed after failure of the top skin which led to the recovery of the load-carrying capacity in the sandwich beams. A similar behavior for the sandwich panels led to the increase of the ultimate strength after appearance of the failure lines on the top skin. The general outcomes of this investigation promise a good influence for the application of elastomeric foam as core material for sandwich structures.

DYNAMICS AND BUCKLING OF SANDWICH PANELS WITH STEPPED FACINGS

2011 ◽  
Vol 11 (04) ◽  
pp. 697-716 ◽  
Author(s):  
CODY H. NGUYEN ◽  
RAMANJANEYA R. BUTUKURI ◽  
K. CHANDRASHEKHARA ◽  
VICTOR BIRMAN
Keyword(s):  
Carrying Capacity ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Structural Response ◽  
Blast Loading ◽  
Attractive Alternative ◽  
Equal Weight ◽  
Load Carrying Capacity ◽  
Structural Problems ◽  
Load Carrying

Sandwich panels have been developed to either produce lighter structures capable of carrying prescribed loads or increase the load-carrying capacity subject to limitations on weight. In these panels, facings carry bending and in-plane loads while the core functions similarly to the web of a beam, mostly resisting transverse shear. Improvements in the load-carrying capacity of sandwich panels can be achieved through modifications in their geometry, boundary conditions, and material distribution. One of the methods recently considered by the authors is based on using facings with a step-wise variable thickness that increases at the critical region of the structure.1 It was illustrated that the strength of a sandwich panel can be considerably enhanced using such stepped facings, without a detrimental increase of the weight. The present paper expands the study of the feasibility of the stepped-facing sandwich panel concept concentrating on three structural problems, i.e. a possible improvement in stability, changes in the natural frequencies, and forced dynamic response to the explosive blast. It is illustrated that the stepped-facing design can improve stability of the panel and its response to blast loading. However, fundamental frequencies of stepped-facing panels decrease compared to those in their conventional equal-weight counterparts. Such decrease is detrimental in the majority of engineering applications representing a limitation of stepped-facing panels. Nevertheless, the usefulness of the stepped-facing design is proven in the problems of bending, stability, and blast loading. Numerous examples presented in the paper validate our suggestion that the combination of a relatively simple manufacturing process and an improved structural response of sandwich panels with stepped facings may present the designer with an attractive alternative to conventional sandwich structures.

Plastic Analysis of Metal Foam Core Sandwich Beam Transversely Loaded by a Flat Punch: Combined Local Denting and Overall Deformation

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
Qing Hua Qin ◽  
T. J. Wang
Keyword(s):  
Metal Foam ◽  
Sandwich Beam ◽  
Plastic Behavior ◽  
Foam Core ◽  
Sandwich Beams ◽  
Low Velocity ◽  
Flat Punch ◽  
Rigid Plastic ◽  
Energy Impact ◽  
Impact Problems

The objective of this work is to investigate the quasi-static plastic behavior of a fully clamped metal foam core sandwich beam transversely loaded by a flat punch. A rigid-plastic beam-on-foundation model is extended to study the local denting deformation of a metal foam core sandwich beam. The effects of local denting and core strength on the overall deformation are incorporated in the analysis. Analytical solutions are derived for three different regimes of post-yield deformation mechanisms. Additionally, finite element results are obtained. Comparisons of the present analytical predictions with numerical, previous experimental, and analytical results are presented, respectively. It is shown that local denting has a significant effect on the finite deflection response of the metal foam core sandwich structure. The load-carrying and energy absorption capacities of sandwich beams may be overestimated if the effect of local denting is neglected in analysis. It is demonstrated that the present analytial model can reasonably predict the behaviors of post-yield deformation of sandwich beams. Moreover, the present analytical method can be extended to predict the low velocity/energy impact problems of sandwich structures.

Analytical Solution for the Large Deflection of Fully Clamped Metallic Foam Sandwich Beam

2008 ◽  
Vol 33-37 ◽  
pp. 559-566 ◽  
Author(s):  
Qing Hua Qin ◽  
Tie Jun Wang
Keyword(s):  
Analytical Solution ◽  
Large Deflection ◽  
Yield Criterion ◽  
Sandwich Beam ◽  
Metallic Foam ◽  
Concentrated Load ◽  
Core Strength ◽  
Load Carrying ◽  
Axial Stretching ◽  
Geometrical Dimensions

A unified yield criterion is proposed in this paper, which is valid for the metallic sandwich sections with various core strength and geometrical dimensions and can reduce to the classical yield criteria for solid monolithic section and sandwich section with weak core, respectively. Then, the unified yield criterion is used to derive the analytical solution for the large deflection of fully clamped metallic sandwich beam subject to a transversely concentrated load, in which the interaction of bending and stretching is considered. Comparisons of the present solutions with experimental results are carried out and good agreements are found. It is seen that the axial stretching induced by large deflection has a significant effect on the deflection of sandwich structure in the post-yield regime, and the load carrying capacity of metallic foam core sandwich beam may be underestimated as the core strength is neglected in analysis.

Investigation of elastomeric foam response applied as core for composite sandwich beams through progressive failure of the beams

2017 ◽  
Vol 21 (2) ◽  
pp. 604-638
Author(s):  
AR Nazari ◽  
MZ Kabir ◽  
H Hosseini Toudeshky
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Progressive Failure ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Beams ◽  
Load Carrying Capacity ◽  
Composite Sandwich ◽  
The Core ◽  
Load Carrying

In this paper an elastomeric foam is applied as core for the composite sandwich beams and load carrying capacity, load–deflection response, and progressive failure are examined through experimental and finite element studies. The objective of this study is to assess the efficiency of elastomeric foam-cored sandwich (EFCS) beams relative to crushable foam-cored sandwich (CFCS) beams. The experimental program consists of two phases. In the first phase, some characterization tests are conducted on the constituent materials of the sandwich beams such as tension, compression, and shear tests on the foam and bending test on the composite beams utilized as skins. Then in the second phase, the performance of the sandwich beams is examined under bending conditions. The load carrying behavior of the sandwich beams is considered dependent on two main features of the constituent materials: (1) the hyperelastic behavior of the foam core and (2) the progressive damage of the composite skins. These characteristics are simulated by the finite element models. Due to elastomeric rather than crushable deformation of the applied foam as the core, the conventional damage modes of the CFCS beams associated to the brittleness of the core material are omitted through load carrying capacity of the EFCS beams. So in the recent sandwich beams by omission of the core failure modes and utilization of compressive residual strength of the top composite skin, considerable energy is absorbed prior to failure of the bottom composite skin. By simulation of the test specimens using FE models, the response of the foam applied as core for the sandwich beams through progressive failure of the beams is investigated. The results show that the elastomeric foam core can provide superior features for the sandwich components especially for the cases in which high energy absorption capacity is required.

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