Failure of a linear Voussoir arch: a laboratory and numerical study

1992 ◽  
Vol 29 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. Stimpson ◽  
M. Ahmed
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Load Capacity ◽  
Failure Process ◽  
Physical Models ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Underground Openings ◽  
Physical Model Tests ◽  
Discrete Crack

The design of underground openings in horizontally layered strata on the basis of classical linear arching theory assumes the ultimate load capacity of the roof is limited by crushing or compressional failure at the centre of the arch or at the abutments. In this study, physical model tests on limestone, granite, and potash beams revealed a progressive failure mechanism dominated by discrete tensile fracturing, a quite different failure process to that assumed by classical theory. Subsequently, discrete crack propagation finite element analysis successfully simulated the failure mechanisms observed in the physical models. Key words : rock mechanics, underground design, roof stability, Voussoir arch, fracture.

Low-order mixed finite element analysis of progressive failure in pressure-dependent materials within the framework of the Cosserat continuum

2017 ◽  
Vol 34 (2) ◽  
pp. 251-271 ◽  
Author(s):  
Hongxiang Tang ◽  
Yuhui Guan ◽  
Xue Zhang ◽  
Degao Zou
Keyword(s):  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Mixed Finite Element ◽  
Failure Process ◽  
Cosserat Continuum ◽  
Element Analysis ◽  
Content Type ◽  
Engineering Problems ◽  
Low Order

Purpose This paper aims to develop a finite element analysis strategy, which is suitable for the analysis of progressive failure that occurs in pressure-dependent materials in practical engineering problems. Design/methodology/approach The numerical difficulties stemming from the strain-softening behaviour of the frictional material, which is represented by a non-associated Drucker–Prager material model, is tackled using the Cosserat continuum theory, while the mixed finite element formulation based on Hu–Washizu variational principle is adopted to allow the utilization of low-order finite elements. Findings The effectiveness and robustness of the low-order finite element are verified, and the simulation for a real-world landslide which occurred at the upstream side of Carsington embankment in Derbyshire reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved. Originality/value The permit of using low-order finite elements is of great importance to enhance computational efficiency for analysing large-scale engineering problems. The case study reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved.

Influence of the Opening’s Position on Seismic Performance of Autoclaved Aerated Concrete Composite Wall with Core Columns

2012 ◽  
Vol 446-449 ◽  
pp. 767-770
Author(s):  
Hui Ge Wu ◽  
Ji Hua Chen ◽  
Jie Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Performance ◽  
Load Capacity ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Finite Element Software ◽  
Autoclaved Aerated Concrete ◽  
Composite Wall ◽  
Aerated Concrete

To study the seismic performance of autoclaved aerated concrete (AAC) block masonry composite wall with reinforced concrete (RC) columns, a non-linear finite element analysis has been carried out for the walls with openings using the finite element software ABAQUS. First results of finite element analysis were verified with experiment results of full-scale specimen. And then the effect of the opening’s position on seismic performance was studied with finite element analysis. The result indicates that the ultimate load capacity and ultimate displacement are both increased with the upward and outward movement of the openings.

scholarly journals Finite Element Analysis of Cracked One-Way Bubbled Slabs Strengthened By External Prestressed Strands

2021 ◽  
Vol 27 (1) ◽  
pp. 45-65
Author(s):  
Falah Hassan Ibrahim ◽  
Ali Hussein Ali
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
The Other ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Line Load ◽  
External Prestressing ◽  
Service Charge ◽  
External Strengthening ◽  
Initial Capacity

Bubbled slabs can be exposed to damage or deterioration during its life. Therefore, the solution for strengthening must be provided. For the simulation of this case, the analysis of finite elements was carried out using ABAQUS 2017 software on six simply supported specimens, during which five are voided with 88 bubbles, and the other is solid. The slab specimens with symmetric boundary conditions were of dimensions 3200/570/150 mm. The solid slab and one bubbled slab are deemed references. Each of the other slabs was exposed to; (1) service charge, then unloaded (2) external prestressing and (3) loading to collapse under two line load. The external strengthening was applied using prestressed wire with four approaches, which are L1-E, L2-E, L1-E2, and L2-E2, where the lengths and eccentricities of prestressed wire are (L1=1800, L2=2400, E1=120 and E2=150 mm). The results showed that each reinforcement approach restores the initial capacity of the bubbled slab and improves it in the ultimate load capacity aspect. The minimum and maximum ultimate strength of strengthened cracked bubbled slab increased by (17.3%-64.5%) and (25.7%-76.3%) than solid and bubbled slab, respectively. It is easier to improve behavior with an increased eccentricity of the prestressed wire than to increase its length.

Comparative Numerical Study between /Steel Fiber Reinforced Concrete and SIFCON on Beam-Column Joint Behavior

2021 ◽  
Vol 1021 ◽  
pp. 138-149
Author(s):  
Ali Wathiq Abdulghani ◽  
Abdulkhaliq A. Jaafer
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Failure ◽  
Ultimate Load ◽  
Numerical Study ◽  
Load Capacity ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Steel Fiber Reinforced Concrete ◽  
Element Analysis

This paper presents a nonlinear finite element analysis of RC beam-column joints. A numerical study carried out through a simulation on beam-column joints failed in flexure presented by experimental study. A verification procedure was performed on two joints by finite element analysis with ANSYS APDL. The verification with the experimental work revealed a good agreement through the load-displacement relationship, ultimate load, and displacement, and crack pattern. Also, the parametric study was implemented which including strengthening the concrete members by a variable ratio of steel fibers with normal ratios (0.5%, 1%, 1.5%, and 2%) and ratios of slurry infiltrated fiber concrete SIFCON (steel fibers up to 4%, 6%, and 8%) in addition to using of partial and full strengthening with and without stirrups. The test results revealed that steel fibers enhanced the flexural strength and ductility of the tested joint. Increase the ratio of steel fibers increased the flexural capacity by (101%, 153%, 177%, and 193%) for the four normal ratios of steel fibers respectively. SIFCON concrete ratios (4%, 6%m and 8%) enhanced ultimate strength by (521%, 802%, and 906%) respectively. The use of steel fibers reinforcement instead of steel rebar enhanced the ultimate load capacity by (101%) with large displacement. Full strengthening method by use of SIFCON presented pure flexural failure with cracks spread in the joint region but use the SIFCON concrete as a partial strengthening changed the failure mode to the shear failure.

scholarly journals Experimental and Numerical Study on the Seismic Performance of Prefabricated Reinforced Masonry Shear Walls

2018 ◽  
Vol 8 (10) ◽  
pp. 1856 ◽  
Author(s):  
Weifan Xu ◽  
Xu Yang ◽  
Fenglai Wang ◽  
Bin Chi
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Compression Ratio ◽  
Numerical Study ◽  
Load Capacity ◽  
Damping Ratio ◽  
Shear Walls ◽  
Inelastic Behavior ◽  
Element Analysis ◽  
Lateral Drift

The seismic performance of prefabricated reinforced concrete block masonry shear walls (PRMSWs) was studied. Five PRMSWs were tested under cyclic loading to evaluate the effect of the axial compression ratio and the distribution of the vertical rebar on the inelastic behavior. Based on the experimental results, the lateral load capacity, failure mode, lateral drift, ductility, stiffness degradation, energy dissipation, and the seismic performance stability of the specimens were analyzed. The finite element analysis of the specimens was conducted with ABAQUS, which agreed quite well with the laboratory findings. Relevant results showed that PRMSW exhibited favorable ductility and energy dissipation. The increase of the compression ratio led to stiffer, but more brittle, inelastic behavior of the specimens that had higher flexural strength. The shear walls that had concentrated vertical rebar at the sides exhibited relatively higher load capacity and less ductility compared to the walls that had evenly distributed rebar. The inelastic lateral drift limit of the PRMSW could be assigned 1/120. The equivalent viscous damping ratio of the PRMSW was 9–13% at ultimate load. These results provide a technical basis for the design and application of the PRMSW structures.

Failure Analysis of Laminate on Influence of the Hole

2012 ◽  
Vol 450-451 ◽  
pp. 590-593
Author(s):  
Yin Huan Yang
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Parametric Design ◽  
Numerical Study ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Failure Process ◽  
Laminated Composite ◽  
Progressive Failure Analysis ◽  
Ultimate Failure

Failure process of laminated composites is performed by progressive failure analysis method. A modified form of Hashin’s failure criterion by Shokrieh is used to investigate the failure, where a sudden degradation model is proposed to reduce engineering material constants. The numerical study of laminated composites is implemented in ANSYS Parametric Design Language (APDL). The initiation and propagation of local damage and response of laminated composite structures from initial loading and ultimate failure are predicted. The model has been validated by comparing numerical results with existing experimental results. And then failure analysis of specimen fabricated from M40J/Ag80 on influence of the hole has been performed by the proposed model.

scholarly journals Finite Element Analysis of Cracked One-Way Bubbled Slabs Strengthened By External Prestressed Strands

2021 ◽  
Vol 27 (1) ◽  
pp. 45-65
Author(s):  
Falah Hassan Ibrahim ◽  
Ali Hussein Ali
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
The Other ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Line Load ◽  
External Prestressing ◽  
Service Charge ◽  
External Strengthening ◽  
Initial Capacity

Bubbled slabs can be exposed to damage or deterioration during its life. Therefore, the solution for strengthening must be provided. For the simulation of this case, the analysis of finite elements was carried out using ABAQUS 2017 software on six simply supported specimens, during which five are voided with 88 bubbles, and the other is solid. The slab specimens with symmetric boundary conditions were of dimensions 3200/570/150 mm. The solid slab and one bubbled slab are deemed references. Each of the other slabs was exposed to; (1) service charge, then unloaded (2) external prestressing and (3) loading to collapse under two line load. The external strengthening was applied using prestressed wire with four approaches, which are L1-E, L2-E, L1-E2, and L2-E2, where the lengths and eccentricities of prestressed wire are (L1=1800, L2=2400, E1=120 and E2=150 mm). The results showed that each reinforcement approach restores the initial capacity of the bubbled slab and improves it in the ultimate load capacity aspect. The minimum and maximum ultimate strength of strengthened cracked bubbled slab increased by (17.3%-64.5%) and (25.7%-76.3%) than solid and bubbled slab, respectively. It is easier to improve behavior with an increased eccentricity of the prestressed wire than to increase its length.

scholarly journals A Numerical Investigation on the Structural Behavior of Deficient Steel Frames Strengthened using CFRP Composite

2018 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Amir Hamzah Keykha
Keyword(s):  
Numerical Study ◽  
Load Capacity ◽  
Steel Frames ◽  
Steel Structures ◽  
Independent Study ◽  
Fiber Reinforced Polymers ◽  
Structural Behavior ◽  
Ultimate Load Capacity ◽  
Hollow Section ◽  
Cfrp Composite

Carbon fiber reinforced polymers (CFRP) is one of the materials that is used to strengthen steel structures. Most studies on CFRP strengthening steel on structures have been done on beams and steel columns. No independent study has studied the effect of CFRP strengthening on the structural behavior of steel frames having initial deficiency.The deficiency in steel structures may be created due to the errors caused by construction and others.This study aims to carry out a numerical study on the efficiency of CFRP sheet on strengthening square hollow section (SHS) steel frames having initial deficiency. Seven specimens, five of which were strengthened using CFRP sheets, were analyzed. ANSYS software was used to analyze the SHS steel frames. The results showed that the coverage length, the width, and the number of CFRP layers have a significant effect on increasing and recovering the ultimate load capacity of the SHS steel frames having initial deficiency.

Considering Catenary Action in Designing End-Restrained Steel Beams in Fire

2005 ◽  
Vol 8 (3) ◽  
pp. 309-324 ◽  
Author(s):  
H. X. Yu ◽  
J. Y. Richard Liew
Keyword(s):  
Design Method ◽  
Load Capacity ◽  
Limit State ◽  
Beam Deflection ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Catenary Action ◽  
In Fire

When a building compartment is subjected to fire attack, there are complex interactions between the fire affected members with the surrounding members. The behaviour of the steel frame members in fire can be drastically different from that of its member in isolation. This paper studies the behaviour of steel beams with the increase of temperature from beam action phase to catenary action phase and until failure. The load bearing mechanism in the catenary action phase is discussed and the failure criterion is defined. A new ultimate limit state based on 15% maximum strain of steel material at elevated temperature is proposed to determine the ultimate load capacity of beams failed in the catenary action phase. Wide ranges of beam parameters including various beam sizes and span lengths with different degrees of end restraints are studied. Comparison of results with those obtained from nonlinear finite element analysis shows that the proposed design method could enhance the critical temperature of steel beams by over 200 °C if proper attention is given to the integrity of connections to resist the catenary force. In this respect, methods to estimate the catenary force and beam deflection are provided.

scholarly journals An Experimental and Numerical Study of Repairs on Composite Substrates with Composite and Aluminum Doublers Using Riveted, Bonded, and Hybrid Joints

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2978 ◽  
Author(s):  
Pitta ◽  
Roure ◽  
Crespo ◽  
Rojas
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Numerical Study ◽  
Progressive Failure ◽  
Adhesive Bond ◽  
Element Analysis ◽  
Fea Model ◽  
Composite Substrate ◽  
Riveted Joints ◽  
Hybrid Joints

In this work, experimental and numerical analyses of repairs on carbon fiber reinforced epoxy (CFRE) substrates, with CFRE and aluminum alloy doublers typical of aircraft structures, are presented. The substrates have a bridge gap of 12.7 mm (simulated crack), repaired with twin doublers joined with riveted, adhesive bonded, and hybrid joints. The performance of the repairs using different doubler materials and joining techniques are compared under static loading. The experimental results show that riveted joints have the lowest strength, while adhesive bonded joints have the highest strength, irrespective of the doubler material. Finite element analysis (FEA) of the studied joints is also performed using commercial FEA tool Abaqus. In the FEA model, point-based fasteners are used for the rivets, and a cohesive zone contact model is used to simulate the adhesive bond. The FEA results indicate that the riveted joints have higher tensile stresses on the metal doublers compared to the composite doublers. As per the failure modes, interestingly, for hybrid joints using composite doublers, the doublers fail due to net-section failure, while, for hybrid joints using metal doublers, it is the composite substrate that fails due to net-section failure. This suggests vulnerability of the composite structures to mechanical fastener holes. Lastly, the Autodesk Helius composite tool is used for prediction of first-ply failure and ply load distribution, and for progressive failure analysis of the composite substrate.

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