scholarly journals Numerical study on LDLT decomposition-based damage locating vector method for truss structures

Author(s):  
Yonghui An ◽  
Bartłomiej Błachowski ◽  
Jinping Ou
2016 ◽  
Vol 38 (3) ◽  
pp. 153-166
Author(s):  
Nguyen Minh Nhan ◽  
Dinh Cong Du ◽  
Vo Duy Trung ◽  
Tran Viet Anh ◽  
Nguyen Thoi Trung

The paper presents a new indicator called normalized energy index (nei) in damage locating vector method (DLV) for detecting multiple damaged positions in beam and truss structures. In the DLV method, a set of load vectors, which is extracted from the change in flexibility matrix between an undamaged structure and a damaged one, is applied as static loads to the undamaged structure which are evaluated via the finite element modeling.  Then, the nei values are computed for each element by using the displacements. In order to verify the accuracy and efficiency of a proposed  indicator, a cantilevered beam and a 14-bay planar truss are considered


2020 ◽  
Author(s):  
Yong-chuan Duan ◽  
Hai-di Qiao ◽  
Fang-fang Zhang ◽  
Yu Liu ◽  
Le Tian ◽  
...  

Abstract The online derivation of material yield is important for consistency control of product quality. Compare with other deformation, bending deformation is more suitable for online identification. The transition portion of bending force stroke curve is related to the yield strength of material, but for a wide set of materials with different thickness and properties, its longer transition curve shows higher identification scattering. In this paper, the yield characteristics strengthening method and the new anti-dispersion identification method are studied to reduce the scattering. It is found that the yield characteristics are comprehensively affected by several factors. The higher yield strength, together with thinner thickness, can weaken the yield characteristics. The thicker material with wider die span can strengthen the yield characteristics. Window vector method (WV) and standardized fitting residual method (SFR) are proposed. Through the numerical study found that the yield load obtained by WV method shows a most accurate correlation with yield strength. A novel piecewise correlation equation is proposed and added a thickness variable to eliminate partial dispersion from varied thickness. Furthermore, this paper uses the experimental data to extract the generalization error of new correlation model fitted by yield loads from WV method, maximum error is below 12%. This method can improve the accuracy and efficiency of online ranking materials.


1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.


2013 ◽  
Author(s):  
Pancheewa Benjamasutin ◽  
◽  
Ponthong Rijana ◽  
Phongchayont Srisuwan ◽  
Aussadavut Dumrongsiri

2013 ◽  
Author(s):  
Artchapong Hassametto ◽  
Preerawadee Chaiboontun ◽  
Chattraporn Prajuabwan ◽  
Laphatrada Khammuang ◽  
Aussadavut Dumrongsiri

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