scholarly journals Analytical Analysis of Distribution of Bending Stresses in Layers of Plywood with Numerical Verification

2019 ◽  
Vol 70 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Andrzej Makowski
Keyword(s):  
Bending Strength ◽  
Plate Theory ◽  
Load Capacity ◽  
Bending Test ◽  
Accurate Estimation ◽  
Numerical Verification ◽  
Classical Plate Theory ◽  
Bending Load ◽  
Bending Stresses ◽  
Distribution Of Stresses

The study presents methods for accurate estimation of bending stresses in the 3-point flexural bending test of plywood, i.e. a wood-based laminate with an alternate crosswise ply configuration. The characteristic bending strength (MOR) and mean modulus of elasticity (MOE) of standard beech plywood was determined using European Standard bending tests EN 310. Correlations were determined between empirically determined bending moduli of the plywood and material moduli of the veneer layer. Calculations were conducted based on the classical plate theory for thin panels comprising the theory of elasticity including the Kirchhoff-Love hypothesis. Rigidity of individual layer was established theoretically in the axial configuration of transformed rigidity matrix values. Numerical laminate models were developed and simulation tests were conducted. Results of experimental and analytical studies were verified using the Finite Element Method (FEM). Analyses were performed in two plywood cross-band arrangement variants. An analysis of the distribution of stresses in individual layers of plywood used an analytical and numerical method assuming the plywood specimen to be a rhombic-anisotropic material. It was found that the bending load capacity of plywood depends on the configuration of individual layers (veneers). Values of stresses originating from bending do not only depend on the distance of the considered plywood layer from the middle layer but also on stiffness in the direction of operating stresses. Bending strength varies in individual directions of the plywood panel. Therefore, the distribution of stresses in individual layers differs from that resulting from the stress distribution for homogeneous isotropic materials. Results are presented in the form of tables, bitmaps, graphs and photographs. The tests were conducted based on the BFU-BU-18 standard beech plywood thickness of 18 mm.

scholarly journals Numerical investigation of the cold-formed I-beams bending strength with different web shapes

2021 ◽  
Vol 16 (59) ◽  
pp. 153-171
Author(s):  
Nadia Kouider ◽  
Yazid Hadidane ◽  
Mohammed Benzerara
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Load Capacity ◽  
Effective Width ◽  
Large Span ◽  
Finite Element Software ◽  
Bending Load ◽  
New Process ◽  
Corrugated Web ◽  
Better Than

The wide use of cold-formed sections (CFS) in the field of steel constructions, favored by the multiple advantages they offer (lightness, ease of installation, etc.), has led us to reflect on a new process for manufacture of metal beams allowing the design of very large span hangars and a reduction in instability problems. This paper presents a study of the theoretical and numerical behavior of a large span CFS beam with different webs, a solid web, a triangular corrugated web, and a trapezoidal corrugated web. These beams are stressed by a concentrated bending load at mid-span. Numerical modeling was done using the finite element software ABAQUS. The results were validated with those theoretically found, based on the effective width method adopted in standard EN1993-1-3. The load capacity and failure modes of the beams were discussed. According to numerical and analytical analysis, corrugated web beams perform better than all other sections.

scholarly journals Retrofitting of Reinforced Concrete Beams Using a Fiberglass Jacketing System

2021 ◽  
Vol 4 (1) ◽  
pp. 44
Author(s):  
Titik P. Artiningsih ◽  
Lirawati L. ◽  
Navi Helmi
Keyword(s):  
Experimental Testing ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Building Collapse ◽  
Load Factors ◽  
Bending Load ◽  
Loading System ◽  
Earthquake Load ◽  
Bending Loads

Building collapse that occurred mostly caused by structure failure in containment earthquake load. Factors that lead to the failure of the beam, among others is beam planning that does not calculate ductility or restraint, resulting decline of beams performance. One way to improve beam strength and ductility are to retrofit the beam by wrapping beams using fiberglass. Research aims to discover the increase amount of bending load capacity from concrete beam that has been retrofitted using jacketing fiberglass. Experimental testing was carried out on beam specimens with a cross section size of 150x200 mm and a length of 1400 mm. Three beam specimens were subjected to bending loads with a three point loading system, with different levels of damage, namely BL1 with collapse at level-1, BL2 at level-2, and BL0 at level-5 as a comparison. Then the BL1 and BL2 were retrofitted by being coated with 2 layers of fiberglass which were glued using epoxy resin. Beams BL-1 and BL-2 are then subjected to a bending test again until they reach level-5 collapse. The test results showed that retrofitted beams were able to increase flexural strength, BL-1 increased 115.15% from the original load and BL-2 increased 52.27% from the original load.

Bending Properties of Five-Layer Biaxial Weft Knitted Fabric Reinforced Composite Materials

2011 ◽  
Vol 391-392 ◽  
pp. 359-363 ◽  
Author(s):  
Wei Geng ◽  
Ye Xiong Qi ◽  
Jia Lu Li
Keyword(s):  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Test Method ◽  
Bending Test ◽  
Bending Properties ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Bending Load

Five-layer biaxial weft knitted (FBWK) fabric is one kind of multilayered biaxial weft knitted (MBWK) fabric. FBWK fabric is made of carbon fiber as inserted yarns and stitched with polyester yarns, and it has been impregnated with epoxy via resin transfer molding (RTM) technique to manufacture the composite plates. The bending properties of the FBWK fabric reinforced composite are studied with the three-point bending test method. The bending properties of the FBWK fabric reinforced composite materials with different fiber volume fraction have been investigated. The results show that the relationship between bending load and deflection is obviously linear before reaching the maximum load. Within a certain range, the bending strength of this kind of composites increases with the fiber volume fraction increasing. When the fiber volume fraction is 57%, the bending strength is 1051.4 MPa.

Surface Crack in a Clamped Circular Plate Subjected to Uniform Lateral Pressure

1980 ◽  
Vol 102 (1) ◽  
pp. 8-13
Author(s):  
H. Abe´ ◽  
M. Ogiwara
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Circular Plate ◽  
Surface Crack ◽  
Flexural Rigidity ◽  
Plate Theory ◽  
Crack Depth ◽  
Classical Plate Theory ◽  
Bending Stresses

The bending of a clamped circular plate containing a surface crack along its edge is discussed. An approximate method of solution, which is based on the classical plate theory, is proposed to obtain the asymptotic behavior of bending stresses along the tip of the crack. The flexural rigidity of the plate is reduced by the crack. The distribution of bending stresses is therefore changed. A plate of nonuniform thickness is introduced which has the equivalent of the flexural rigidity of the cracked plate under consideration. The bending stress intensity factor is evaluated with the aid of the equivalent plate. It is found that the stress intensity factor increases with the crack depth for shallow cracks, and it decreases when the depth exceeds a certain value.

Measuring orthotropic bending stiffness components of Pinus pinaster by the virtual fields method

2018 ◽  
Vol 53 (8) ◽  
pp. 556-565 ◽  
Author(s):  
José Xavier ◽  
Fabrice Pierron
Keyword(s):  
Pinus Pinaster ◽  
Plate Theory ◽  
Mechanical Tests ◽  
Bending Test ◽  
Material Parameter Identification ◽  
Classical Plate Theory ◽  
Full Field ◽  
Reflective Coating ◽  
Identification Approach ◽  
Heterogeneous Plate

Orthotropic stiffness components of Pinus pinaster Ait. wood are simultaneously determined by means of a heterogeneous plate bending test. The proposed inverse identification approach couples full-field slope measurements provided by deflectometry with the virtual fields methods. Wooden plates oriented in the longitudinal–radial and longitudinal–tangential material planes were manufactured. A procedure was implemented to allow suitable specular reflective coating of the wooden plates, required in the deflectometry technique. Reconstructed curvature fields, applied load and plate dimensions were input in virtual fields methods for material parameter identification, assuming Kirchhoff–Love classical plate theory. Several virtual fields and load cases were analysed to address the identifiability of the method. The values of the orthotropic elastic constants obtained from the proposed approach were found in good agreement with regard to reference ones for the same species and determined from classical tensile, compression and shear mechanical tests.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
AMIR SYAFIQ SAMSUDIN ◽  
MOHD HISBANY MOHD HASHIM ◽  
SITI HAWA HAMZAH ◽  
AFIDAH ABU BAKAR
Keyword(s):  
Reinforced Concrete ◽  
Bending Strength ◽  
Steel Fibre ◽  
Concrete Slab ◽  
Future Application ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Conventional Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Bending Load

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.

scholarly journals Experimental Investigation on the Influence of Fiber Path Curvature on the Mechanical Properties of Composites

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2602
Author(s):  
Huaqiao Wang ◽  
Jihong Chen ◽  
Zhichao Fan ◽  
Jun Xiao ◽  
Xianfeng Wang
Keyword(s):  
Tensile Strength ◽  
Path Planning ◽  
Composite Laminates ◽  
Bending Strength ◽  
High Strength ◽  
Bending Test ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Fiber Path ◽  
Path Curvature

Automated fiber placement (AFP) has been widely used as an advanced manufacturing technology for large and complex composite parts and the trajectory planning of the laying path is the primary task of AFP technology. Proposed in this paper is an experimental study on the effect of several different path planning placements on the mechanical behavior of laminated materials. The prepreg selected for the experiment was high-strength toughened epoxy resin T300 carbon fiber prepreg UH3033-150. The composite laminates with variable angles were prepared by an eight-tow seven-axis linkage laying machine. After the curing process, the composite laminates were conducted by tensile and bending test separately. The test results show that there exists an optimal planning path among these for which the tensile strength of the laminated specimens decreases slightly by only 3.889%, while the bending strength increases greatly by 16.68%. It can be found that for the specific planning path placement, the bending strength of the composite laminates is significantly improved regardless of the little difference in tensile strength, which shows the importance of path planning and this may be used as a guideline for future AFP process.

Sinusoidal Torsional Buckling of Bars of Angle Section Under Bending Loads, as a Problem in Plate Theory

1951 ◽  
Vol 18 (3) ◽  
pp. 285-292
Author(s):  
H. J. Plass
Keyword(s):  
Infinite Series ◽  
Plate Theory ◽  
Ritz Method ◽  
Compressive Load ◽  
Series Solutions ◽  
Torsional Buckling ◽  
Bending Load ◽  
Angle Section ◽  
Bending Loads

Abstract Timoshenko has applied plate theory to each leg of an angle-section bar to determine the critical compressive load needed to cause sinusoidal torsional buckling. In this paper his idea is used to calculate the critical bending load needed to cause sinusoidal torsional buckling of an angle bar. The bending is assumed to be applied so that the extreme fibers of the angle are in compression, the vertex in tension. Approximate results are first obtained by means of the Rayleigh-Ritz method. The approximate deflection functions from which the energy terms are computed are based upon certain infinite-series solutions. After having obtained approximate results, exact values are obtained, using the approximate values as a guide to limit the amount of calculation. The results of this calculation are shown in Fig. 5, where they are compared with those predicted by bar theory. Differences between the two theories become more noticeable as the bar becomes short compared to its flange width. It is found that the critical bending load becomes larger very rapidly as the ratio of length to width of the flanges decreases. Bar theory predicts no such increase. The reason for this difference is explained.

Dynamical Behaviors of Sinusoidal Nanocomposite Plates Subjected to Thermomechanical Loads

2021 ◽  
Author(s):  
Vu Ngoc Viet Hoang ◽  
Dinh Gia Ninh
Keyword(s):  
Thermal Environment ◽  
Plate Theory ◽  
Micromechanical Model ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Sine Function ◽  
Classical Plate Theory ◽  
Wolfram Mathematica ◽  
Number Of Cycles

In this paper, a new plate structure has been found with the change of profile according to the sine function which we temporarily call as the sinusoidal plate. The classical plate theory and Galerkin’s technique have been utilized in estimating the nonlinear vibration behavior of the new non-rectangular plates reinforced by functionally graded (FG) graphene nanoplatelets (GNPs) resting on the Kerr foundation. The FG-GNP plates were assumed to have two horizontal variable edges according to the sine function. Four different configurations of the FG-GNP plates based on the number of cycles of sine function were analyzed. The material characteristics of the GNPs were evaluated in terms of two models called the Halpin–Tsai micromechanical model and the rule of mixtures. First, to verify this method, the natural frequencies of new non-rectangular plates made of metal were compared with those obtained by the Finite Element Method (FEM). Then, the numerical outcomes are validated by comparing with the previous papers for rectangular FGM/GNP plates — a special case of this structure. Furthermore, the impacts of the thermal environment, geometrical parameters, and the elastic foundation on the dynamical responses are scrutinized by the 2D/3D graphical results and coded in Wolfram-Mathematica. The results of this work proved that the introduced approach has the advantages of being fast, having high accuracy, and involving uncomplicated calculation.

Bending and flexural-buckling strength of steel members considering strain-rate-effects at elevated temperatures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fuminobu Ozaki ◽  
Takumi Umemura
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Transient State ◽  
Bending Test ◽  
Content Type ◽  
Buckling Strength ◽  
Flexural Buckling ◽  
Steel Members ◽  
Collapse Temperature

PurposeIn this study, the bending strength, flexural buckling strength and collapse temperature of small steel specimens with rectangular cross-sections were examined by steady and transient state tests with various heating and deformation rates.Design/methodology/approachThe engineering stress and strain relationships for Japan industrial standard (JIS) SN400 B mild steels at elevated temperatures were obtained by coupon tests under three strain rates. A bending test using a simple supported small beam specimen was conducted to examine the effects of the deformation rates on the centre deflection under steady-state conditions and the heating rates under transient state conditions. Flexural buckling tests using the same cross-section specimen as that used in the bending test were conducted under steady-state and transient-state conditions.FindingsIt was clarified that the bending strength and collapse temperature are evaluated by the full plastic moment using the effective strength when the strain is equal to 0.01 or 0.02 under fast strain rates (0.03 and 0.07 min–1). In contrast, the flexural buckling strength and collapse temperature are approximately evaluated by the buckling strength using the 0.002 offset yield strength under a slow strain rate (0.003 min–1).Originality/valueRegarding both bending and flexural buckling strengths and collapse temperatures of steel members subjected to fire, the relationships among effects of steel strain rate for coupon test results, heating and deformation rates for the heated steel members were minutely investigated by the steady and transient-state tests at elevated temperatures.

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