Elastic Rebound of a Blast Door Under Explosion Loadings

2018 ◽  
Vol 18 (10) ◽  
pp. 1871011
Author(s):  
Qiushi Yan ◽  
Dong Guo
Keyword(s):  
Aspect Ratio ◽  
Shear Force ◽  
Plastic Range ◽  
Dynamic Shear ◽  
Load Duration ◽  
Rebound Effects ◽  
Elastic Rebound ◽  
Conventional Weapons ◽  
Plastic Stage ◽  
Elastic Stage

Rebound effects can be caused for a blast door under explosion loadings of conventional weapons. Such effects reaching a certain extent can lead to severe reversed stresses and even destroy the hinge and lock system before the door leaf. In this study, an analytical model for the elastic rebound of a blast door under explosion loadings was proposed and analyzed. Based on the calculations, the effects of aspect ratio and load duration on the rebound behavior were analyzed. Furthermore, for extension of the analysis from the elastic to plastic range, comparison of the solutions with the analytical ones was made. The results showed that the positive and negative dynamic shear force peaks of the blast door deceased gradually with the aspect ratio, whereas the rebound strength was inversely proportional to the load duration. For blast doors entering into the plastic stage, the rebound behavior was similar to the elastic stage, implying that the design of a blast door can be based on its characteristics in elastic stage.

scholarly journals ANALISIS GAYA GEMPA PADA BANGUNAN RUMAH TINGGAL DI WILAYAH GEMPA TINGGI

2018 ◽  
Vol 7 (2) ◽  
pp. 57-64
Author(s):  
Alfian Wiranata Zebua
Keyword(s):  
Structural Analysis ◽  
Shear Force ◽  
Structure Model ◽  
Dynamic Shear ◽  
Earthquake Loads ◽  
Story Drift ◽  
Loads Analysis ◽  
Support Reactions ◽  
Static Shear

Abstract : Four stories building was used as structure model. Static earthquake loads distribution were determined according to SNI 1726:2012. The effect of dynamic earthquake loads also considered. The result of structural analysis determined using ETABS. It were static shear force 1.082,64 KN and dynamic shear force, Fx = 1.057 KN and Fy = 983,5 KN. Colomn and beam forces were also determined. Support reactions and joint displacements were determined through structural analysis. Mass modal participation has been reached over 90% at mode 5. Story drift was still smaller than the allowable story drift.Keywords : earthquake loads analysis, residential building.Abstrak:Model struktur yang dianalisis yaitu gedung beraturan lantai 4 untuk rumah tinggal. Distribusi beban gempa statik diperoleh sesuai dengan SNI 1726:2012. Pengaruh beban gempa dinamik juga diperhitungkan. Hasil analisis struktur diperoleh antara lain besaran gaya geser statik 1.082,64 KN dan gaya geser dinamik, Fx = 1.057 KN dan Fy = 983,5 KN. Besaran gaya elemen kolom dan balok juga diperoleh. Reaksi tumpuan serta perpindahan titik buhul dapat diketahui dari hasil analisis yang dilakukan. Pada mode 5, partisipasi massa model yang dianalisis sudah mencapai 90%.Simpangan antar lantai yang terjadi pada model struktur tidak melebihi simpangan yang diijinkan.Kata kunci : analisis gaya gempa, bangunan rumah tinggal.

Validation of Magnetic Resonance Elastography by Dynamic Shear Testing in the Shear Wave Regime

2010 ◽  
Author(s):  
Ruth J. Okamoto ◽  
Erik H. Clayton ◽  
Kate S. Wilson ◽  
Philip V. Bayly
Keyword(s):  
Magnetic Resonance ◽  
Shear Modulus ◽  
Shear Wave ◽  
Shear Force ◽  
Magnetic Resonance Elastography ◽  
Dynamic Shear ◽  
Complex Shear Modulus ◽  
Shear Testing ◽  
Complex Shear ◽  
Propagating Shear

Magnetic resonance elastography (MRE) is a novel experimental technique for probing the dynamic shear modulus of soft biological tissue non-invasively and in vivo. MRE utilizes a standard MRI scanner to acquire images of propagating shear waves through a specimen that is subject to external harmonic mechanical actuation; commonly at frequencies in excess of 200Hz. At steady state, the wavelength of the propagating shear wave can be used to estimate the shear modulus of the tissue. Dynamic shear testing (DST) is also used to characterize soft biomaterials. Thin samples of the material are subject to oscillatory shear strains. Shear force is measured, and converted to shear stress — analysis of this data of a range of frequencies gives a complex shear modulus. The data analysis method assumes that the shear displacement is linear and shear strain is constant through the thickness of the sample. In soft tissues, very thin samples are typically used to avoid inertial effects at higher frequencies. As the thickness of the sample decreases, it is more difficult to cut samples of uniform thickness and to maintain structural integrity of the sample. Thus in practice, measurements of brain tissue properties using DST without inertial correction are limited to low frequencies. In this work, we bridge the frequency regimes of DST and MRE by testing thick samples using DST over a range of frequencies that generates a shear wave in the sample, with a corresponding peak in the measured shear force. The frequency and magnitude of this peak give additional information about the complex shear modulus of the material being tested, and these DST results are interpreted using a finite element (FE) model of the sample. Using this method, we can obtain an estimate of shear modulus in an intermediate frequency regime between that of standard DST and MRE.

Nonlinear Analysis of Steel and Concrete Composite Beams Strengthened with Prestressed FRP Bars

2012 ◽  
Vol 256-259 ◽  
pp. 775-778
Author(s):  
Jia Yang
Keyword(s):  
Nonlinear Analysis ◽  
Composite Beam ◽  
Composite Beams ◽  
Deformation Curve ◽  
Shear Connectors ◽  
Plastic Stage ◽  
The Moment ◽  
Analysis Mode ◽  
Frp Bars ◽  
Elastic Stage

Steel and concrete composite beam is a kind of composite beam which the steel and the concrete are connected by shear connectors. Now, many experts and scholars have carried out many experimental research and theoretical analysis about it. But, steel and concrete composite beams strengthened with prestressed FRP bars have not been studied. Based on the structure, the nonlinear analysis mode of steel and concrete composite beams strengthened with prestressed FRP bars is proposed, the calculating program is researched. The relationships between moment and curvature, also between load and deformation of steel and concrete composite beams strengthened with prestressed FRP bars are obtained. The results show that the moment-curvature curve and load-deformation curve of steel and concrete composite beams strengthened with prestressed FRP bars can be separated to elastic stage, elastic-plastic stage and plastic stage.

scholarly journals Transition zone in Bearing Capacity Problem from Plasticity Method, Discrete Element Method and Laboratory tests

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Yungming Cheng
Keyword(s):  
Discrete Element Method ◽  
Bearing Capacity ◽  
Transition Zone ◽  
Laboratory Tests ◽  
Friction Angle ◽  
Discrete Element ◽  
Element Approach ◽  
Plastic Stage ◽  
Elastic Stage ◽  
The Continuum

<p>In this paper, the classical bearing capacity problem and the logspiral transition zone are re-considered from a continuum plasticity approach as well as discrete element approach. In the discrete element approach, the bearing capacity problem is considered from the elastic stage, plastic stage to the final rupture stage. It is found that there are noticeable differences in the failure mechanism between the continuum and discontinuum analyses, and the well-known logspiral transition zone is also not apparent in both the discrete element approach, plasticity approach as well as the laboratory tests. With the increase in the friction angle of soil, the transition zone is becoming more like a wedge zone than a logspiral zone as found from the present study. </p>

scholarly journals THE ELASTOPLASTIC CALCULATION OF FRAMES USING THE DISPLACEMENT METHOD

2019 ◽  
Vol 15 (3) ◽  
pp. 120-130
Author(s):  
Alexander Potapov
Keyword(s):  
Lower Boundary ◽  
Displacement Method ◽  
Margin Of Error ◽  
Limiting Load ◽  
Plastic Stage ◽  
Plastic Zones ◽  
Two Stages ◽  
Previous Loading ◽  
Incremental Equations ◽  
Elastic Stage

We proposed a method for calculating statical indeterminacy frames taking into account plastic defor­mations, which is based on the use of a schematized diagram of material with hardening. Two types of standard beams with supports are used during the implementation of the displacement method (DM) and the elastic solu­tion of the problem: “fixed” - “pinned” and “fixed” - “fixed”, but unlike the elastic solution, standard beams con­tain plastic zones (PZs). So as the stresses in these zones did not exceed the limit of yielding in the nonlinear frame calculation, we took measures to transform the PZs into equal strength plastic zones (ESPZ). The calcula­tions were made for both types of beams for all single and load impacts. The frame calculation consists of two stages (elastic and plastic). At the elastic stage, we determine an elastic moment diagram and the corresponding load. For a practical use of the DM in a nonlinear frame calculation, we introduced a simplifying prerequisite sup­plementing the well-known hypotheses of the classical version of the method, and formulated a Statement of the limiting load. According to the Statement, each length of the PZ can correspond to the lower boundary of the lim­iting load. The plastic stage of the calculation is performed at a given length of the PZ using the method of se­quential loadings. At each loading stage, incremental equations are written using the DM equations, which estab­lish relations between incremental moments and the incremental load, that allows you to get the resulting moment diagram. This diagram represents a sum of the elastic diagram and the diagrams of incremental moments at all previous loading stages. According to the resulting diagram, we calculate the length of the PZ, together with the limiting load. The calculation is considered complete if the length of the PZ does not exceed the specified value within the margin of error.

Flexural Behavior of Concrete-Filled FRP-Steel Composite Circular Tubes

2011 ◽  
Vol 243-249 ◽  
pp. 1316-1320 ◽  
Author(s):  
Yang Wei ◽  
Gang Wu ◽  
Zhi Shen Wu ◽  
Dong Sheng Gu
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Concrete Beams ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Composite Tube ◽  
Circular Tubes ◽  
Steel Composite ◽  
Plastic Stage ◽  
Elastic Stage

Three large-scale concrete-filled FRP-steel composite circular tubes and a control steel tube were tested to investigate flexural behavior. The effects of FRP and composite with different types of FRP with various ultimate strains were investigated. The study demonstrated the important effect of FRP, and showed that the load-displacement curves of FRP-steel composite tube beams could be divided into four stages: elastic stage, plastic stage, hardening stage and residual stage. An additional decline stage was gained for multi-fiber with different ultimate strains and steel composite tube concrete beams. FRP could increase the ultimate bearing capacity and bring the hardening stage after steel tube yielding, and a certain degree of stiffness would be achieved to avoid the “zero stiffness”. The composite of a variety of FRP could relax fracture failure for the FRP-steel composite steel concrete beams, realized the successive rupture of fiber in batches and changed the failure modes.

scholarly journals Soil Interaction of Building Frame Resting on Clayey Soil: Effect of Change of Aspect Ratio

2019 ◽  
Vol 8 (2) ◽  
pp. 2875-2881
Keyword(s):  
Numerical Analysis ◽  
Aspect Ratio ◽  
Shear Force ◽  
Clayey Soil ◽  
Bending Moment ◽  
Column Height ◽  
Building Frame ◽  
Aspect Ratios ◽  
Conventional Analysis ◽  
Percentage Difference

In General the framed structures are analyzed by considering that their bases are totally rigid (or) hinged. However, depending on relative rigidities of soil foundation and super structure the foundation undergoes deformation. In structural design the designers ignore the settlement response of the framed structure. The distribution of load on column and moment in framed structure transmitted to the foundation in the substructure has a crucial role in structural stiffness. Hence the analysis of the single bay single storied building frame resting on soil (CLAYEY SOIL) is taken for present study. The numerical analysis is carried out using ANSYS R16.0 by assuming that the base of the frame is resting on Soil (CLAYEY SOIL). The constant column height of 3M, while beam length varies of 6M,12M, &18M and their respective aspect ratio’s of 2,4&6. And for each aspect ratio the modulus of sub-grade reaction for clayey soil varies from 0.01 to 0.050N/mm3 . The conventional analysis which assumes that the frame is resting on rigid support is carried out using ANSYS R16.0 by assuming the fixed base for the columns in the building frame when modulus of sub grade reaction varies from 0.01 to 0.050 N/mm3 . The following conclusions have been drawn from the study, The percentage difference of shear force and bending moment in the beam, The axial load, shear force and, bending moment values in the column, and The bending moment values (Mx)&(Mz) in the shell and footing settlements in the shell for various aspect ratios of the frame obtained from both conventional and finite element analysis are not having considerable difference. Comparing numerical analysis which considers soil interaction with the conventional method, the conventional analysis is shown higher values SF and B.M in the beam, footing and columns. In conventional analysis it is assumed that the footings are resting on a rigid medium so footing settlements are zero. While observing the footing settlements in reality they undergo with some settlement therefore these settlement values are observed for numerical analysis which are used for the design to satisfy codal requirements.

Performance Comparison of Beams with Different Stirrups

2012 ◽  
Vol 598 ◽  
pp. 539-542
Author(s):  
Hai Tao Wan ◽  
Li Li
Keyword(s):  
Bearing Capacity ◽  
High Strength ◽  
Performance Comparison ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Practical Application ◽  
Loading Test ◽  
Plastic Stage ◽  
Elastic Stage ◽  
Better Than

High strength concrete and high strength reinforcement technology have been quite mature,but there are still less in practical application of china.CRB550 grade reinforcement is formed by HPB235 reinforcement through cold-working, which strength is much improved,but ductility did not change much. 6 reinforced concrete beams with different stirrups are designed for low cyclic loading test. Contrasting the test results, in the elastic stage, beam with CRB550 stirrups and beam with HPB235 stirrups is very similar in bearing capacity and deformation performance.However, in the elastic-plastic stage, beam with CRB550 stirrups in bearing capacity and deformation performance is better than beam with HPB235 stirrups.Therefore, it is proved that CRB550 reinforcement can replace HPB235 reinforcement as stirrups in RC beams.

Design Capacity of T-Strut Subject to Compressive Force

2010 ◽  
Vol 163-167 ◽  
pp. 550-556
Author(s):  
Xiao Li Xiong ◽  
Li Bin Jin ◽  
Hui Wang
Keyword(s):  
Residual Stress ◽  
Compressive Force ◽  
Buckling Analysis ◽  
Plastic Range ◽  
Shear Center ◽  
Nonlinear Buckling ◽  
Design Capacity ◽  
Axis Of Symmetry ◽  
Nonlinear Buckling Analysis ◽  
Elastic Stage

T-struts subject to centroid compression buckle flexural-torsionally about their axis of symmetry. When the force is applied at the shear center of the section, T-struts buckle either flexurally or torsionally without coupling of flexure with twisting. Although the buckling load of shear center loading is greater than that of centroid loading, i.e. T-struts in elastic stage provide larger resistance to buckling about their axis of symmetry when the compression is applied at the shear center in lieu of the centroid of the section, T-struts with defect such as fabrication error, load eccentricity and residual stress always buckles in the elastic-plastic range actually, and the design capacity decrease by shifting the working line of a T-section compression chord to the shear center. That peculiarity is verified by the nonlinear buckling analysis of T-struts models in ANSYS.

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