scholarly journals CONSTITUTIVE MODEL FOR TIMBER FRACTURE USED FOR FE SIMULATION OF LVL ARCH

2018 ◽  
Vol 15 ◽  
pp. 109-113 ◽  
Author(s):  
Eliška Šmídová ◽  
Petr Kabele
Keyword(s):  
Constitutive Model ◽  
Shear Fracture ◽  
Material Model ◽  
Compact Tension ◽  
Bending Test ◽  
Yellow Poplar ◽  
Laminated Veneer Lumber ◽  
Four Point Bending ◽  
Element Simulation ◽  
Gt Element

Non-linear finite element simulation of four-point bending test of a small-size arch is described in this paper. The arch of 780mm span is made of Yellow Poplar (<em>Liriodendron tulipifera</em>) laminated veneer lumber (LVL) and it is manufactured with a through crack parallel to fibers in the middle of its crown. 2D homogeneous orthotropic constitutive model of tensile and shear fracture in timber that has been recently developed and implemented into ATENA<sup>®</sup> element software by the authors is used for the numerical calculation. Both standard and compact tension (CT) test results are used for the material model calibration. Results show that the model successfully reproduces the increasing part of the load-displacement response. Furthermore, the model can capture the most distinctive features of the crack pattern.

scholarly journals Geometry Effects in Four-Point Bending Test for Thin Sheet Studied by Finite Element Simulation

2016 ◽  
Vol 57 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Xiaolong Dong ◽  
Hongwei Zhao ◽  
Lin Zhang ◽  
Hongbing Cheng ◽  
Jing Gao
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Thin Sheet ◽  
Bending Test ◽  
Four Point Bending ◽  
Element Simulation ◽  
Four Point Bending Test ◽  
Geometry Effects

Finite element simulation of fracture toughness testing of 20MnMoNi55 steel and the effect of loading rate on reference temperature

2020 ◽  
pp. 146442072095667
Author(s):  
Swagatam Paul ◽  
Snehasish Bhattacharjee ◽  
Sanjib Kumar Acharyya ◽  
Prasanta Sahoo
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Loading Rate ◽  
Flow Characteristics ◽  
Material Model ◽  
Compact Tension ◽  
Reference Temperature ◽  
Viscoplastic Material ◽  
Element Simulation

Fracture toughness of ferritic steel in the ductile-to-brittle transition zone is scattered and probabilistic owing to embrittlement. Use of master curve along with the reference temperature ( T0) adopted in ASTM E-1921 is widely accepted for characterization of this embrittlement. Reference temperature is a measure of embrittlement in the temperature scale. Factors affecting fracture toughness like geometry and loading rate are expected to influence the reference temperature. In the present study, the role of the loading rate on the reference temperature for 20MnMoNi55 steel is assessed experimentally using compact tension C(T) and three-point bend (TPB) specimens. Finite element simulation of tests at different loading rates and cryogenic temperature are carried out using a suitable viscoplastic material model that incorporates flow characteristics of the material for varying displacement rates and cryogenic temperatures. Results from simulation studies are compared with experimental ones.

An Analysis of the Local Buckling Collapse Behavior of an Aluminum Square Tube under Concentrated Bending Moment Loads

2004 ◽  
Vol 261-263 ◽  
pp. 633-638 ◽  
Author(s):  
Sung Hyuk Lee ◽  
Nak Sam Choi
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Bending Moment ◽  
Bending Test ◽  
Aluminum Tube ◽  
Four Point Bending ◽  
Element Simulation ◽  
Steel Bars ◽  
Four Point Bending Test ◽  
Collapse Behavior

To analyze the bending collapse behavior of an aluminum square tube under the bending moment load, a finite element simulation for the four-point bending test has been performed. Using an aluminum tube beam specimen partly inserted with two steel bars, local buckling deformation near the center of the tube beam was induced. Simulated moment-rotation angle curve obtained during the post-collapse period of the aluminum tube with steel bars were in good agreement with experimental result, which was comparable to the result obtained from Kecman's theory. Using a combination of the four-point bending test and its finite-element simulation, analysis of the local buckling and the bending collapse behavior of an aluminum tube beam could be quantitatively accomplished.

Effects of Non-Associated Flow Rule on AHSS Shear Fracture

2016 ◽  
Vol 725 ◽  
pp. 465-470
Author(s):  
Hong Woo Lee ◽  
Kyung Seok Oh
Keyword(s):  
Shear Fracture ◽  
Large Strain ◽  
High Strength Steels ◽  
Material Model ◽  
Failure Criteria ◽  
Bending Test ◽  
Forming Limit ◽  
Flow Rule ◽  
Elastoplastic Material ◽  
Associated Flow Rule

Recently, advanced high strength steels (AHSSs) have been widely applied to the structural parts of vehicles thanks to their good combination of strength and ductility. When one makes parts with AHSSs, however, fractures in sharp corners of the parts are frequently observed below forming limit, which is normally defined by strain based FLC(Forming Limit Curve). This phenomenon is well-known as “Shear Fracture”. Recent researches point out that additional numerical techniques should be considered in order to predict it accurately. Kim et al. [1] suggested that shear fracture can be predictable with continuum-based finite elements rather than conventional shell elements, and more constitutive informations for large strain thermo-mechanical simulation are needed to improve accuracy. Luo and Wierzbicki [2] showed that shear fracutre in stretch-bending test can be fully characterized by proposed MMC(Modified Mohr-Coulomb). This paper shows that solid-shell approach based on hyper-elastoplastic material model enables one to properly predict shear fracture pheonomenon without any special failure criteria. Furthermore, the effects of non-associated flow rule on shear fracture will be also discussed with several numerical examples.

Constitutive Model for Timber Fracture under Tensile and Shear Loads

2015 ◽  
Vol 784 ◽  
pp. 137-144 ◽  
Author(s):  
Eliska Smidova ◽  
Petr Kabele
Keyword(s):  
Constitutive Model ◽  
Shear Fracture ◽  
Compact Tension ◽  
Radiata Pine ◽  
Inelastic Behavior ◽  
Finite Element Software ◽  
Shear Loads ◽  
Smeared Crack Approach ◽  
Smeared Crack ◽  
Small Deformations

A 2D homogeneous orthotropic constitutive model of tensile and shear fracture in timber based on fixed smeared crack approach has been developed and implemented in ATENA®finite element software. The model captures (1) elastic and inelastic behavior in small deformations range, (2) material orthotropy, both in linear and non-linear range, (3) cracking across or along fibers, and (4) behavior under unloading/reloading. In this contribution we present model validation through numerical simulations of compact tension shear (CTS) tests of Radiata Pine timber.

scholarly journals Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1701
Author(s):  
Ken Suzuki ◽  
Ryohei Nakagawa ◽  
Qinqiang Zhang ◽  
Hideo Miura
Keyword(s):  
Graphene Nanoribbons ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Bending Test ◽  
Gauge Factor ◽  
Four Point Bending ◽  
Current Voltage ◽  
Highly Sensitive ◽  
Current Voltage Relationship

In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.

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