Compression behavior and failure modes of wood-based lattice core sandwich structure with improved relative density

2021 ◽  
pp. 073168442110093
Author(s):  
Lifeng Wang ◽  
Yingcheng Hu ◽  
Shuai Li ◽  
Gaoyuan Ye ◽  
Zelong Li
Keyword(s):  
Relative Density ◽  
Sandwich Structure ◽  
Failure Modes ◽  
High Strength ◽  
Test Results ◽  
Plate Structures ◽  
Compression Behavior ◽  
Potential Applications ◽  
Shear Buckling ◽  
Lattice Core

In response to growing interest in lightweight, high-strength wood-based engineering materials, a lattice core sandwich structure made of plywood and birch dowels with improved relative density in its core was designed and fabricated. Flatwise and edgewise compressive experiments were performed to investigate the mechanical behavior of the sandwich structure. The effect of relative density on the mechanical properties and failure mode of the structure under flatwise compression was discussed. The theoretical and experimental flatwise compression test results showed good agreement. The results of the edgewise compressive tests of the sandwich structure indicated that face sheet wrinkling, crushing, and macro-shear buckling of the core were the main failure modes. The wood-based lattice sandwich structure has potential applications in the construction industry as beam and plate structures for buildings.

Study on Transverse Shear Behavior of CFRP Sandwich Structure with M-Pattern Folded Core

2014 ◽  
Vol 670-671 ◽  
pp. 173-176 ◽  
Author(s):  
Li Xin Cong ◽  
Yu Guo Sun
Keyword(s):  
Relative Density ◽  
Sandwich Structure ◽  
Failure Modes ◽  
Pure Shear ◽  
Shear Loading ◽  
Bonding Performance ◽  
The Face ◽  
Folded Core ◽  
Shear Buckling ◽  
Failure Loads

In order to solve the problem of the face/core bonding performance of the sandwich structure, this paper proposed a M - pattern folded sandwich structure. Structural performance in direct (pure) shear was investigated for sandwich structure. FE-Analytical of sandwich structure strength under shear loading condition was presented for possible failure modes. Panels with core of different thickness were tested for different failure modes and the mechanical properties. In general, the measured failure loads showed good agreement with the FE-analytical predictions.The results shown that failure modes of the sandwich structure with low relative density were shear buckling and fracture of thin-walled of cores, respectively. For the sandwich structure with high relative density, the dominant failure mode was interfacial debonding of face/cores, and the initiating failure along the ends of the specimens.

scholarly journals Optimization and Mechanical Properties of Fabricated 2D Wood Pyramid Lattice Sandwich Structure

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 607
Author(s):  
Dongxia Yang ◽  
Changsheng Fan ◽  
Yingcheng Hu
Keyword(s):  
Mechanical Properties ◽  
Sandwich Structure ◽  
Failure Modes ◽  
High Strength ◽  
Test Results ◽  
Element Analysis ◽  
Compression Performance ◽  
Truss Core ◽  
Unit Cells ◽  
Better Than

In order to obtain a lightweight, high strength, and large design space wooden sandwich structure to meet the needs of modern wooden buildings, the mechanical properties of a fabricated 2D wooden pyramid lattice sandwich structure were studied. In this paper, the mechanical and compressive properties of the specimens with different arrangement of Lattice Sandwich unit cells are studied. The upper and lower panels and core materials are made into a single unit cell by inserting glue, and the prefabricated 2D wooden pyramid lattice truss core sandwich structure is prepared by the mortise tenon splicing method. The results show that the arrangement of the unit cells in the specimen has a significant effect on the bearing capacity, energy absorption, and failure mode of the specimen, and the flat compression performance of the panel-reinforced specimen is better than that of the specimen with unreinforced veneer. The results of finite element analysis are consistent with the test results. The main failure modes are core fracture and panel cracking. These results provide a theoretical basis for the system design of wood-based lattice sandwich structure in the future.

Compressive effect of jute fiber corrugated lattice sandwich structure

2019 ◽  
Vol 39 (5-6) ◽  
pp. 209-218
Author(s):  
Shuguang Li ◽  
Runsheng Hu ◽  
Jin Cheng ◽  
Yingcheng Hu
Keyword(s):  
Sandwich Structure ◽  
Failure Modes ◽  
Shear Failure ◽  
Jute Fiber ◽  
Factors Affecting ◽  
Specific Strength ◽  
Out Of Plane ◽  
Theoretical Predictions ◽  
Shear Buckling ◽  
The Cost

A lattice sandwich structure mainly consisting of jute fiber and resin epoxy was prepared. Two configurations were established, and six out-of-plane compression experiments were conducted to identify the factors affecting the mechanical properties of the samples. The specific strength of the 2D corrugated lattice truss with the struts at 30° (I1) was 3 times stronger than that of the sample with sandwich struts at 45°. The specific strength of I1 was 3.9 times stronger than that of the Kagome structure prepared using Cu–2%Be. The cost performance with respect to the specific strength of the structure I1 was 161.7 times higher than that of the Kagome structure prepared using Cu–2%Be. Three failure modes were considered, and theoretical predictions were made separately. The failure modes in the experiment were mainly shear failure and shear buckling failure in sandwich struts.

scholarly journals Natural Silkworm Cocoon Composites with High Strength and Stiffness Constructed in Confined Cocooning Space

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1214 ◽  
Author(s):  
Lan Cheng ◽  
Xiaoling Tong ◽  
Zhi Li ◽  
Zulan Liu ◽  
Huiming Huang ◽  
...  
Keyword(s):  
High Performance ◽  
High Strength ◽  
Homogeneous Layer ◽  
Dense Layer ◽  
Test Results ◽  
Young’S Moduli ◽  
Layer Structures ◽  
Potential Applications ◽  
Silkworm Cocoon ◽  
Strength And Stiffness

In this study, using round paper tubes (PTs) and rectangular cardboard boxes (CBs) as external constraints to control the size of the cocooning space, we fabricated a series of modified silkworm cocoons (PT cocoons and CB cocoons). Their microstructures, morphologies, compositions, and mechanical properties were characterized and compared with normal silkworm cocoons. These two kinds of modified silkworm cocoons exhibit dense and homogeneous layer structures. Tensile test results indicate that above a size limit of cocooning space, their tensile strengths, Young’s moduli, and strain energy densities increase with the decrease in cocooning space. Especially in comparison with the normal cocoons, the tensile strength and Young’s modulus of the PT-14 cocoon increase by 44% and 100%, respectively. Meanwhile, PT cocoons and CB cocoons, except PT-12, also possess better peeling resistance than normal cocoons. Owing to the dense structure and low porosity, the modified cocoons form robust fiber networks that result in high strength and toughness. This study provides a green and efficient method to fabricate mechanically enhanced silkworm cocoons with special shapes and dense layer structures. The method can be easily subjected to further modification processes and has potential applications in the production of high-performance green cocoon composites and biomimetic materials.

Seismic behavior of normal-strength concrete-filled precast high-strength concrete centrifugal tube columns

2019 ◽  
Vol 23 (4) ◽  
pp. 614-629
Author(s):  
Shaohua Zhang ◽  
Xizhi Zhang ◽  
Shengbo Xu ◽  
Xingqian Li
Keyword(s):  
Axial Compression ◽  
High Strength Concrete ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Concrete Strength ◽  
High Strength ◽  
Test Results ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength

This study reports the cyclic loading test results of normal-strength concrete-filled precast high-strength concrete centrifugal tube columns. Seven half-scale column specimens were tested under cyclic loads and axial compression loads to investigate their seismic behavior. The major parameters considered in the test included axial compression ratio, filled concrete strength, and volumetric stirrup ratio. The structural behavior of each specimen was investigated in terms of failure modes, hysteresis behavior, bearing capacity, dissipated energy, ductility, stiffness degradation, drift capacity, and strain profiles. Test results revealed that the concrete-filled precast high-strength concrete centrifugal tube column exhibited good integral behavior, and the failure modes of all columns were ductile flexural failures. Lower axial compression ratio and higher volumetric stirrup ratio resulted in more satisfactory ductile performance. In contrast, the filled concrete strength has a limited influence on the structural behavior of concrete-filled precast high-strength concrete centrifugal tube columns. Based on the limit analysis method, the calculation formula for the bending capacity of the concrete-filled precast high-strength concrete centrifugal tube column was developed, and the results predicted from the formulas were in good agreement with the experiment results.

scholarly journals Castellated Steel Beams-A Torsional Analysis

2020 ◽  
Vol 9 (5) ◽  
pp. 536-540
Keyword(s):  
Failure Modes ◽  
Weight Ratio ◽  
High Strength ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Moment Capacity ◽  
Flexure Mechanism ◽  
Shear Buckling ◽  
Castellated Beam

Practice of castellated beams (CBs) or perforated beams for several structures speedily gaining petition. This is because of the increased depth in the segment, high strength to weight ratio, light in weight, easy to erect, economical, and stronger. The principal advantages of the castellated beam are an attractive provision, an increase in vertical bending stiffness, & ease of service provision. The CBs is prepared from its virgin sections i.e. I beam by cutting it in a zigzag or any suitable cutting pattern and again rejoined it by welding therefore depth of the resulting section increases. The load-carrying capacity of the parent I section is increased with the same quantity of material and weight, due to an increase in depth of beams. Web post-buckling and lateral-torsional buckling failure occur when these beams are subjected to loading, this is the effect of an increase in depth of the castellated beams. There are five basic failure modes associated with castellated steel beams that need to be taken care of 1) Development of flexure mechanism. 2) Lateral-torsional buckling 3) Vierendeel mechanism 4) rupture of the welded joint in a web post 5) shear buckling of a web post. Therefore, in this research paper, an effort has been made to estimate the torsional moment capacity castellated beam for hexagonal or honeycomb opening with 300, 450, 600 & sinusoidal opening with different fillet radii.

Methodology for multiscale design and optimization of lattice core sandwich structures for lightweight hopper railcars

2020 ◽  
Vol 234 (21) ◽  
pp. 4224-4238 ◽  
Author(s):  
Danial Molavitabrizi ◽  
Jeremy Laliberte
Keyword(s):  
Sandwich Structure ◽  
Sandwich Panel ◽  
Failure Modes ◽  
Minimum Weight ◽  
Strength Properties ◽  
Optimized Design ◽  
Design And Optimization ◽  
Floor Panel ◽  
Octet Truss ◽  
Lattice Core

This research is focused on developing new lightweight structures for railcars based on a pre-selected material, i.e. Al 2099. The goal is to design a new sandwich structure with an octet truss lattice core for a floor panel of a hopper freight railcar designed to meet North American standards. For that, mesoscale to macroscale design of the sandwich panel was performed. In mesoscale design, relative density, elastic properties, strength properties, and failure criterion of the lattice unit cell were investigated. In the next step, these properties were used as inputs for macroscale design, i.e. design of the whole sandwich structure. Multiple failure modes associated with the lateral loading of a sandwich panel were analyzed. These equations in conjunction with the minimum weight target led to an optimization problem, and the minimum required thicknesses were obtained. Finally, the new optimized design was validated by comparing different finite element simulations with the exact analytical equations. By using this type of structure, a 53% weight reduction was achieved on the floor panel which ultimately led to an estimated 12.5% reduction in the weight of the whole freight railcar body.

Influence of Freeze-Thaw Cycles on Bonded Interface Performance between CFRP and High Strength Concrete

2014 ◽  
Vol 638-640 ◽  
pp. 1516-1520 ◽  
Author(s):  
Lei Hong ◽  
Run Min Duo ◽  
Su Yan Wang ◽  
Lu Xi Li
Keyword(s):  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Bonded Joints ◽  
Test Results ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Reinforced Polymer

The bonded joints between carbon fiber reinforced polymer (CFRP) and high strength concrete subjected to different freeze-thaw cycles were studied and the results were analyzed. The test results indicate that with the increase of freeze-thaw cycles, effective bond length, ultimate bond load and ultimate global slip response will decrease. But it has little effects on initial stripping load. The failure modes change from adhesive debonding to shear failure of concrete.

scholarly journals Clogging of pervious concrete pile caused by soil piping: an approximate experimental study

2018 ◽  
Vol 55 (7) ◽  
pp. 999-1015 ◽  
Author(s):  
Xinzhuang Cui ◽  
Jiong Zhang ◽  
Darhao Chen ◽  
Shucai Li ◽  
Qing Jin ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Relative Density ◽  
Conductivity Measurement ◽  
High Strength ◽  
Test System ◽  
Pervious Concrete ◽  
Laboratory Simulation ◽  
Sand Particle ◽  
Test Results ◽  
Potential Disadvantage

Due to their high permeability and high strength, pervious concrete piles (PCPs) can improve ground bearing capacity. However, clogging of pervious concrete in practice is a potential disadvantage. To investigate the clogging mechanism of PCPs due to sand piping, a series of laboratory simulation tests is conducted on a developed hydraulic conductivity test system. This testing demonstrates the effects of pervious concrete porosity, grading of fine movable particles, mix ratio of skeleton particles to movable particles, relative density of soil, and distance between PCPs on PCP clogging. The experimental test results show that the hydraulic conductivity of PCP decreases for approximately 70 min and then becomes relatively stable. In addition, it is observed that PCP clogging rarely occurs in cases of low pervious concrete porosity, small movable sand particle size, high sand relative density, and large pile distance. The results also show that measurement of electrical conductivity can be an alternative method of hydraulic conductivity measurement. Based on the test results, preliminary clogging models are proposed.

Composite Solutions for Deck Catamarans

2018 ◽  
Vol 55 (1) ◽  
pp. 1-4
Author(s):  
Elena Felicia Beznea ◽  
Ionel Chirica ◽  
Adrian Presura ◽  
Ionel Iacob
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sandwich Structure ◽  
High Strength ◽  
Total Weight ◽  
External Loading ◽  
Strength Analysis ◽  
Allowable Stress ◽  
The Finite Element Method ◽  
Inland Navigation

The paper is treating the strength analysis of the main deck structure of an inland navigation catamaran for 30 passengers. The main deck should have high stiffness and high strength to resist to external loading and endure high stresses from combined bending and torsion loads. Different materials for sandwich structure of the deck have been analysed by using the Finite Element Method in order to determine the solution which accomplish better designing criteria regarding allowable stress and deformations and total weight.

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