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.

Structural Performance of Fiber-Reinforced Polymer Honeycomb Sandwich Panels: Evaluation of Size Effect and Wrap Strengthening

2003 ◽  
Vol 1845 (1) ◽  
pp. 191-199 ◽  
Author(s):  
Ondrej Kalny ◽  
Robert J. Peterman ◽  
Guillermo Ramirez ◽  
C. S. Cai ◽  
Dave Meggers
Keyword(s):  
Carrying Capacity ◽  
Ultimate Load ◽  
Sandwich Panels ◽  
Fiber Reinforced Polymer ◽  
Load Carrying Capacity ◽  
Flexural Capacity ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Honeycomb Sandwich ◽  
Ultimate Load Carrying Capacity

Stiffness and ultimate load-carrying capacities of glass fiber-reinforced polymer honeycomb sandwich panels used in bridge applications were evaluated. Eleven full-scale panels with cross-section depths ranging from 6 to 31.5 in. (152 to 800 mm) have been tested to date. The effect of width-to-depth ratio on unit stiffness was found to be insignificant for panels with a width-to-depth ratio between 1 and 5. The effect of this ratio on the ultimate flexural capacity is uncertain because of the erratic nature of core-face bond failures. A simple analytical formula for bending and shear stiffness, based on material properties and geometry of transformed sections, was found to predict service-load deflections within 15% accuracy. Although some factors influencing the ultimate load-carrying capacity were clearly identified in this study, a reliable analytical prediction of the ultimate flexural capacity was not attained. This is because failures occur in the bond material between the outer faces and core, and there are significant variations in bond properties at this point due to the wet lay-up process, even for theoretically identical specimens. The use of external wrap layers may be used to shift the ultimate point of failure from the bond (resin) material to the glass fibers. Wrap serves to strengthen the relatively weak core–face interface and is believed to bring more consistency in determining the ultimate load-carrying capacity.

Blast loading influence on load carrying capacity of I-column

2015 ◽  
Vol 104 ◽  
pp. 107-115 ◽  
Author(s):  
Lukasz Mazurkiewicz ◽  
Jerzy Malachowski ◽  
Pawel Baranowski
Keyword(s):  
Carrying Capacity ◽  
Blast Loading ◽  
Load Carrying Capacity ◽  
Load Carrying

Implication of Anisotropy of Face-Sheets and Core Layer Materials on the Load Carrying Capacity of Advanced Sandwich Panels: Linear and Nonlinear Responses

2000 ◽  
Author(s):  
Liviu Librescu
Keyword(s):  
Carrying Capacity ◽  
Sandwich Structure ◽  
Sandwich Panels ◽  
Core Layer ◽  
Anisotropic Materials ◽  
Load Carrying Capacity ◽  
The Core ◽  
Load Carrying ◽  
The Face ◽  
Sandwich Shells

Abstract This paper deals with a comprehensive geometrically nonlinear theory of shallow sandwich shells that includes also the effect of the initial geometric imperfections. It is assumed that the face-sheets of the sandwich structure are built-up from anisotropic materials layers, whereas the core layer from an orthotropic material. As a result of its features the structural model can provide important information related to the load carrying capacity of sandwich structures in the pre- and postbuckling ranges. Moreover, by using the directionality properties of face-sheets materials, possibilities of enhancing the load carrying capacity of sandwich shells/plates are reached. Selected numerical illustrations emphasizing these features are presented and pertinent conclusions on the beneficial implications of anisotropy of face-sheets and core layer materials upon the load-carrying capacity of sandwich panels are emphasized. Under the present study, the sandwich structure consists of a thick core-layer bonded by the face-sheets that consist of composite anisotropic materials, symmetrically laminated with respect to the mid-surface of the core-layer. The initial geometric imperfection consisting of a stress free initial transversal deflection, will be also incorporated in the study. The loads under which the nonlinear response will be analyzed consist basically of uniaxial/biaxial compressive edge and lateral loads.

Structural Behaviour of Precast Lightweight Foamed Concrete Sandwich Panel (PLFP) with Double Shear Truss Connectors under Eccentric Load: Preliminary Result

2013 ◽  
Vol 795 ◽  
pp. 414-418
Author(s):  
I. Ahmad ◽  
W.I. Goh ◽  
S. Samsuddin ◽  
N. Mohamad ◽  
M.H.A. Rahman ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Sandwich Panel ◽  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Structural Behaviour ◽  
Eccentric Load ◽  
Double Shear ◽  
Load Carrying ◽  
Foamed Concrete ◽  
Ultimate Load Carrying Capacity

Recent years in Malaysia, precast concrete sandwich panel gained its popularity in building industries due to its economic advantages, superior thermal and structural efficiency. This paper studied the structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with double shear truss connectors under eccentric load. Preliminary results were analysed and studied to obtain the ultimate load carrying capacity, load-deflection profiles and strain distribution across the panel thickness at mid depth. The achieved ultimate load carrying capacity of PLFP due to eccentric load from the experimental work was compared with values calculated from classical formulas (if it is more than 1 comparison) developed by previous researchers. Preliminary results showed that, the use of double shear truss connectors in PLFP was able to improve its ultimate load carrying capacity to sustain eccentric load and achieve certain compositeness reaction in between the wythes.

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.

scholarly journals Fiber Reinforced Polymer Culvert Bridges—A Feasibility Study from Structural and LCC Points of View

2021 ◽  
Vol 6 (9) ◽  
pp. 128
Author(s):  
Reza Haghani ◽  
Jincheng Yang ◽  
Marte Gutierrez ◽  
Christopher D. Eamon ◽  
Jeffery Volz
Keyword(s):  
Carrying Capacity ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Attractive Alternative ◽  
Load Carrying Capacity ◽  
Fiber Reinforced ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Composite Bridges

Soil–steel composite bridges (SSCB) have become increasingly popular for short-span bridges as an alternative to concrete slab bridges mainly due to their low initial cost, rapid manufacture, simplified construction, and geometrical adaptability. SSCBs have a variety of applications and can be used over waterways or roadways. While conventional bridges tend to lose their load-carrying capacity due to degradation, SSCBs gain strength because of backfill soil consolidation. However, the load carrying capacity and integrity of such structures highly depends on the condition and load-carrying capacity of the steel arch element. A major drawback of SSCBs, especially those located on waterways or with poor drainage, is corrosion and subsequent loss of cross-sectional capacity. Unfortunately, the inspection of such bridges is not straightforward and any damage/collapse will be very costly to repair/replace. Fiber reinforced polymer (FRP) composites offer an attractive alternative to replace the steel in these types of bridges. FRP composites have significantly improved durability characteristics compared to steel, which will reduce maintenance costs and improve life-cycle costs (LLCs). This paper presents a new concept to use glass FRP as a construction material to construct soil–FRP composite bridges (SFCB). Various aspects of design and manufacturing are presented along with results and conclusions from a case study involving alternative bridge designs in steel and FRP composites.

Effect of Core Thickness on Load Carrying Capacity of Sandwich Panel Behavior Beyond Yield Limit

2011 ◽  
pp. 171-181
Author(s):  
Salih N. Akour ◽  
Hussein Maaitah ◽  
Jamal F. Nayfeh
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Carrying Capacity ◽  
Sandwich Panel ◽  
Core Material ◽  
Load Carrying Capacity ◽  
Yield Limit ◽  
The Core ◽  
Load Carrying ◽  
Core Thickness

Sandwich Panel has attracted designer’s interest due to its light weight, excellent corrosion characteristics and rapid installation capabilities. It has been implemented in many industrial application such as aerospace, marine, architectural and transportation industry. Its structure consists of two face sheets and core. The core is usually made of material softer than the face sheets. The current investigation unveils the effect of core thickness on the behavior of Sandwich Panel beyond the yield limit of core material. The core thickness is investigated by utilizing univariate search optimization technique. The load is applied in quasi–static manner (in steps) till face sheets reach the yield limit. Simply supported panel from all sides is modeled using a finite element analysis package. The model is validated against numerical and experimental cases that are available in the literature. In addition, experimental investigation has been carried out to validate the finite element model and to verify some selected cases. The finite element results show very good agreement with the previous work and the experimental investigation. The study presents that the load carrying capacity of the panel increases as the core material goes beyond the yield point. Also, increasing core thickness to a certain limit delays the occurrence of core yielding and gives opportunity to face sheets to yield first.

scholarly journals Experimental and Numerical Analysis of Nonlinear Flexural Behaviour of Lattice-Web Reinforced Foam Core Composite Sandwich Panels

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jiye Chen ◽  
Hai Fang ◽  
Weiqing Liu ◽  
Yujun Qi ◽  
Lu Zhu
Keyword(s):  
Numerical Analysis ◽  
Carrying Capacity ◽  
Sandwich Panels ◽  
Foam Core ◽  
Load Carrying Capacity ◽  
Flexural Behaviour ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Load Carrying ◽  
The Face

This paper conducted experimental and numerical analysis of the nonlinear flexural behaviour of lattice-web reinforced foam core composite sandwich panels. Composite sandwich panels composed of a polyurethane (PU) foam core with glass fibre-reinforced polymer (GFRP) composites as the face sheets and lattice webs were fabricated through the vacuum infusion moulding process (VIMP). The flexural behaviour of these composite sandwich panels were experimentally investigated under both uniformly distributed and concentrated loading scenarios. The results showed that reinforced lattice webs can significantly increase the flexural stiffness and load-carrying capacity of sandwich panels and effectively postpone the onset of interfacial debonding failure between the face sheets and core. The effects of the lattice-web height and spacing on the ductility and load-carrying capacities of the sandwich panels were also analysed. Several numerical simulations on lattice-web reinforced foam core composite sandwich panels under concentrated loadings were also conducted. The effectiveness of the finite element (FE) model was validated by the experimental work. Parametric studies indicated that thicker face sheets and lattice webs can remarkably increase the load-carrying capacity. Moreover, the load-carrying capacity and midspan deflection were hardly affected by the foam density.

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