scholarly journals Time-History Analysis of Composite Materials with Rectangular Microstructure under Shear Actions

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6439
Author(s):  
Marco Colatosti ◽  
Nicholas Fantuzzi ◽  
Patrizia Trovalusci

It has been demonstrated that materials with microstructure, such as particle composites, show a peculiar mechanical behavior when discontinuities and heterogeneities are present. The use of non-local theories to solve this challenge, while preserving memory of the microstructure, particularly of internal length, is a challenging option. In the present work, composite materials made of rectangular rigid blocks and elastic interfaces are studied using a Cosserat formulation. Such materials are subjected to dynamic shear loads. For anisotropic media, the relative rotation between the local rigid rotation and the microrotation, which corresponds to the skewsymmetric part of strain, is crucial. The benefits of micropolar modeling are demonstrated, particularly for two orthotropic textures of different sizes.

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .


2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.


Author(s):  
Fatemeh Jalayer ◽  
Hossein Ebrahimian ◽  
Andrea Miano

AbstractThe Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.


Author(s):  
Fan Bu ◽  
Caifu Qian

In this paper, two finite element models are established for a super-large storage tank with or without a floating roof on the medium level. Time-history analysis with consideration of fluid-solid coupling for the deformation of tank wall and medium sloshing during or after an earthquake is performed with the emphasis on the effects of the floating roof. It is found that the upper part of tank is more sensitive to the earthquake action than the lower part. The wind girders and the reinforcing rings play a big role in limiting the radial deformation of the upper part of the tank wall. The floating roof has little effect on the tank wall deformation, but it is effective in suppressing the medium sloshing during the earthquake. After the earthquake, the radial deformation of the tank wall attenuates quickly, but the sloshing attenuation of the medium presents a slow progress and the floating roof inhibits the sloshing attenuation of the medium.


2012 ◽  
Vol 594-597 ◽  
pp. 886-890 ◽  
Author(s):  
Gan Hong ◽  
Mei Li ◽  
Yi Zhen Yang

Abstract. In the paper, take full account of energy dissipation operating characteristics. Interlayer shear-frame structure for the analysis of the Wilson-Θmethod ELASTOPLASTIC schedule, the design of a nonlinear dynamic time history analysis procedure. On this basis, taking into account the restoring force characteristics of the energy dissipation system, the inflection point in the restoring force model treatment, to avoid a result of the calculation results of distortion due to the iterative error. A frame structure seismic response time history analysis results show that: the framework of the energy dissipation significantly lower than the seismic response of the common framework, and its role in the earthquake when more significant.


2016 ◽  
Vol 858 ◽  
pp. 145-150
Author(s):  
Yu Liang Zhao ◽  
Zhao Dong Xu

This paper discussed an elastic-plastic time-history analysis on a structure with MR dampers based on member model, in which the elastoplastic member of the structure is assumed to be single component model and simulated by threefold line stiffness retrograde model. In order to obtain better control effect, Linear Quadratic Gaussian (LQG) control algorithm is used to calculate the optimal control force, and Hrovat boundary optimal control strategy is used to describe the adjustable damping force range of MR damper. The effectiveness of the MR damper based on LQG algorithm to control the response of the structure was investigated. The results from numerical simulations demonstrate that LQG algorithm can effectively improve the response of the structure against seismic excitations only with acceleration feedback.


2013 ◽  
Vol 756-759 ◽  
pp. 4482-4486
Author(s):  
Chun Gan ◽  
Xue Song Luo

In recent years, frequent earthquakes have caused great casualties and economic losses in China. And in the earthquake, damage of buildings and the collapse is the main reason causing casualties. Therefore, in the design of constructional engineering, a seismicity of architectural structure is the pressing task at issue. Through time history analysis method, this paper analyzes the time history of building structural response and then it predicts the peak response of mode by response spectrum analysis. Based on this, this paper constructs a numerical simulation model for the architecture by using finite element analysis software SATWE. At the same time, this paper also calculates the structure seismic so as to determine the design of each function structure in architectural engineering design and then provides reference for the realization of earthquake-resistant building.


Author(s):  
Chi Woong Ra ◽  
Eun-Ho Lee ◽  
Chang Kyun Lee ◽  
JinWoo Im ◽  
No-Cheol Park

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