Numerical Investigation of Post Buckling Strength and Failure Modes in Advanced Grid Stiffened Structure under Thermal-Mechanical Loads

2007 ◽  
Vol 334-335 ◽  
pp. 613-616
Author(s):  
Rui Xiang Bai ◽  
Bo Chen ◽  
Cheng Yan ◽  
Lin Ye ◽  
Ze Cheng Li ◽  
...  
Keyword(s):  
Failure Modes ◽  
Mechanical Load ◽  
Progressive Failure ◽  
Shear Deformation Theory ◽  
Failure Behavior ◽  
Linear Deformation ◽  
Failure Characteristics ◽  
Buckling Strength ◽  
Stiffened Structures ◽  
Post Buckling

This work investigated the post buckling strength and failure behavior of advanced grid stiffened structures (AGS) under thermal-mechanical load using a finite element method. Based on the first order shear deformation theory (FSDT), Von Karman non-linear deformation assumption, and a progressive failure criterion, the buckling, large deformation，local failure modes in the AGS were studied. The thermal effect was also analyzed. By some numerical examples, the failure characteristics of the AGS were discussed.

scholarly journals Crack Initiation, Propagation, and Failure Characteristics of Jointed Rock or Rock-Like Specimens: A Review

2019 ◽  
Vol 2019 ◽  
pp. 1-31 ◽  
Author(s):  
Ri-hong Cao ◽  
Ping Cao ◽  
Hang Lin ◽  
Xiang Fan ◽  
Chunyang Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Crack Initiation ◽  
Failure Modes ◽  
Failure Process ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Failure Behavior ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Natural Rock

Rock masses are heterogeneous materials containing a large number of discontinuities, and the failure of the natural rock mass is induced by the crack propagation and coalescence of discontinuities, especially for the rock mass around tunnel or underground space. Because the deformation or failure process of jointed rock mass exhibits strongly nonlinear characteristics, it is also very difficult to predict the strength and failure modes of the rock mass. Therefore, it is very necessary to study the failure mechanisms of jointed rock mass under different stress conditions. Apart from the stress condition, the discontinuities geometry also has a significant influence on the mechanical behavior of jointed rock mass. Then, substantial, experimental, and numerical efforts have been devoted to the study of crack initiation, propagation, and coalescence of rock or rock-like specimens containing different kinds of joints or fissures. The purpose of this review is to discuss the development and the contribution of the experiment test and numerical simulation in failure behavior of jointed rock or rock-like specimens. Overall, this review can be classified into three parts. It begins by briefly explaining the significance of studying these topics. Afterwards, the experimental and numerical studies on the strength, deformation, and failure characteristics of jointed rock or rock-like materials are carried out and discussed.

scholarly journals 3-D Numerical Study on Progressive Failure Characteristics of Marbles under Unloading Conditions

2020 ◽  
Vol 10 (11) ◽  
pp. 3875 ◽  
Author(s):  
Yongjun Zhang ◽  
Sijia Liu ◽  
Miaomiao Kou ◽  
Zaiquan Wang
Keyword(s):  
Failure Modes ◽  
Numerical Study ◽  
Progressive Failure ◽  
Numerical Results ◽  
Failure Characteristics ◽  
Geometric Conditions ◽  
Confining Pressures ◽  
Ultimate Failure ◽  
Unloading Rate ◽  
Scientists And Engineers

3-D particle-based discrete element method (PB-DEM) was employed to numerically study the mechanical and progressive failure characteristics of pre-fissured marble specimens under conventional triaxial unloading conditions. The microscopic parameters of PB-DEM for marble materials were calibrated using comparison with the previous experimental data. To systematically investigate the mechanical properties and the progressive failure characteristics of pre-fissured marble specimens under the unloading conditions, a series of numerical specimens were simulated. The effects of fissure geometric conditions, initial confining pressures, and unloading rates on the mechanical and failure behaviors were explored via simulations. The present numerical results indicate that peak strength increased as the initial confining pressures increased or the unloading rate decreased. Crack coalescence types and the ultimate failure modes in the pre-fissured marble specimens were significantly affected by the unloading stress paths. The present numerical results provide a better understanding of unloading mechanical and failure characteristics to scientists and engineers in rock mechanics and rock engineering.

scholarly journals Fatigue Resistance and Failure Behavior of Penetration and Non-Penetration Laser Welded Lap Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xiangzhong Guo ◽  
Wei Liu ◽  
Xiqing Li ◽  
Haowen Shi ◽  
Zhikun Song
Keyword(s):  
Fatigue Resistance ◽  
Failure Modes ◽  
Plate Thickness ◽  
High Stress ◽  
Lap Joints ◽  
Failure Behavior ◽  
Passenger Cars ◽  
Plate Fracture ◽  
The Difference ◽  
Railway Passenger

AbstractPenetration and non-penetration lap laser welding is the joining method for assembling side facade panels of railway passenger cars, while their fatigue performances and the difference between them are not completely understood. In this study, the fatigue resistance and failure behavior of penetration 1.5+0.8-P and non-penetration 0.8+1.5-N laser welded lap joints prepared with 0.8 mm and 1.5 mm cold-rolled 301L plates were investigated. The weld beads showed a solidification microstructure of primary ferrite with good thermal cracking resistance, and their hardness was lower than that of the plates. The 1.5+0.8-P joint exhibited better fatigue resistance to low stress amplitudes, whereas the 0.8+1.5-N joint showed greater resistance to high stress amplitudes. The failure modes of 0.8+1.5-N and 1.5+0.8-P joints were 1.5 mm and 0.8 mm lower lap plate fracture, respectively, and the primary cracks were initiated at welding fusion lines on the lap surface. There were long plastic ribs on the penetration plate fracture, but not on the non-penetration plate fracture. The fatigue resistance stresses in the crack initiation area of the penetration and non-penetration plates calculated based on the mean fatigue limits are 408 MPa and 326 MPa, respectively, which can be used as reference stress for the fatigue design of the laser welded structures. The main reason for the difference in fatigue performance between the two laser welded joints was that the asymmetrical heating in the non-penetration plate thickness resulted in higher residual stress near the welding fusion line.

scholarly journals Analytical Investigation of Tension Loaded Deformed Rebar Anchors in Concrete

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 442-458
Author(s):  
Sandip Chhetri ◽  
Rachel A. Chicchi
Keyword(s):  
Test Data ◽  
Parametric Study ◽  
Failure Modes ◽  
Experimental Testing ◽  
Analytical Investigation ◽  
Failure Behavior ◽  
Capacity Design ◽  
Simulation Results

Experimental testing of deformed rebar anchors (DRAs) has not been performed extensively, so there is limited test data to understand their failure behavior. This study aims to expand upon these limited tests and understand the behavior of these anchors, when loaded in tension. Analytical benchmark models were created using available test data and a parametric study of deformed rebar anchors was performed. Anchor diameter, spacing, embedment, and number of anchors were varied for a total of 49 concrete breakout simulations. The different failure modes of anchors were predicted analytically, which showed that concrete breakout failure is prominent in the DRA groups. The predicted concrete breakout values were consistent with mean and 5% fractile concrete capacities determined from the ACI concrete capacity design (CCD) method. The 5% fractile factor determined empirically from the simulation results was kc = 26. This value corresponds closely with kc = 24 specified in ACI 318-19 and ACI 349-13 for cast-in place anchors. The analysis results show that the ACI CCD formula can be conservatively used to design DRAs loaded in tension by applying a kc factor no greater than 26.

scholarly journals Numerical simulation method for predicting a flood hydrograph due to progressive failure of a landslide dam

Landslides ◽  
2021 ◽  
Author(s):  
S. Takayama ◽  
S. Miyata ◽  
M. Fujimoto ◽  
Y. Satofuka
Keyword(s):  
Field Experiments ◽  
Failure Modes ◽  
Initial Conditions ◽  
Progressive Failure ◽  
Landslide Dam ◽  
Failure Model ◽  
Reservoir Water ◽  
Erosion Model ◽  
Flood Hydrograph ◽  
Overtopping Erosion

AbstractReducing the damage due to landslide dam failures requires the prediction of flood hydrographs. Although progressive failure is one of the main failure modes of landslide dams, no prediction method is available. This study develops a method for predicting progressive failure. The proposed method consists of the progressive failure model and overtopping erosion model. The progressive failure model can reproduce the collapse progression from a dam toe to predict the longitudinal dam shape and reservoir water level when the reservoir water overflows. The overtopping erosion model uses these predicted values as the new initial conditions and reproduces the dam erosion processes due to an overtopping flow in order to predict a flood hydrograph after the reservoir water overflows. The progressive failure model includes physical models representing the intermittent collapse of a dam slope, seepage flow in a dam, and surface flow on a dam slope. The intermittent collapse model characterizes the progressive failure model. It considers a stabilization effect whereby collapse deposits support a steep slope. This effect decreases as the collapse deposits are transported downstream. Such a consideration allows the model to express intermittent, not continuous, occurrences of collapses. Field experiments on the progressive failure of a landslide dam were conducted to validate the proposed method. The progressive failure model successfully reproduced the experimental results of the collapse progression from the dam toe. Using the value predicted by the progressive failure model, the overtopping erosion model successfully reproduced the flood hydrograph after the reservoir water started to overflow.

Fuzzy risk assessment for electro-optical target tracker

2016 ◽  
Vol 33 (6) ◽  
pp. 830-851 ◽  
Author(s):  
Soumen Kumar Roy ◽  
A K Sarkar ◽  
Biswajit Mahanty
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Linear Equations ◽  
Mode Analysis ◽  
Failure Behavior ◽  
Membership Functions ◽  
Design And Development ◽  
Effect Analysis ◽  
Content Type ◽  
Criticality Analysis

Purpose – The purpose of this paper is to evolve a guideline for scientists and development engineers to the failure behavior of electro-optical target tracker system (EOTTS) using fuzzy methodology leading to success of short-range homing guided missile (SRHGM) in which this critical subsystems is exploited. Design/methodology/approach – Technology index (TI) and fuzzy failure mode effect analysis (FMEA) are used to build an integrated framework to facilitate the system technology assessment and failure modes. Failure mode analysis is carried out for the system using data gathered from technical experts involved in design and realization of the EOTTS. In order to circumvent the limitations of the traditional failure mode effects and criticality analysis (FMECA), fuzzy FMCEA is adopted for the prioritization of the risks. FMEA parameters – severity, occurrence and detection are fuzzifed with suitable membership functions. These membership functions are used to define failure modes. Open source linear programming solver is used to solve linear equations. Findings – It is found that EOTTS has the highest TI among the major technologies used in the SRHGM. Fuzzy risk priority numbers (FRPN) for all important failure modes of the EOTTS are calculated and the failure modes are ranked to arrive at important monitoring points during design and development of the weapon system. Originality/value – This paper integrates the use of TI, fuzzy logic and experts’ database with FMEA toward assisting the scientists and engineers while conducting failure mode and effect analysis to prioritize failures toward taking corrective measure during the design and development of EOTTS.

Thermal Post-Buckling Analysis of Functionally Graded Composite Plates with Nonlinear Aerodynamic Forces

2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim
Keyword(s):  
Material Properties ◽  
Numerical Solutions ◽  
Virtual Work ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Governing Equations ◽  
Functionally Graded Composite ◽  
Post Buckling

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis

Research on the post-buckling strength of screw composite thin plate with large deflection

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 204-215
Author(s):  
Lei Zhang ◽  
Tianhua Zhou ◽  
Yanchun Li ◽  
Liurui Sang
Keyword(s):  
Thin Plate ◽  
Large Deflection ◽  
Buckling Strength ◽  
Post Buckling
Sign in / Sign up

Export Citation Format

Share Document