Martínez-Rubin de Celis E¹, E Rivas-Robles², L Martínez-Corral³, J Frías-Ramírez¹, J Orozco-Vidal¹, M Fortis-Hernández¹, MA Segura Castruita¹

Phyton-International Journal of Experimental Botany, Vol.80, pp. 189-192, 2011, DOI:10.32604/phyton.2011.80.189

Abstract Soil compaction or increase of soil bulk density (Da) as a result of applied loads is expressed as an increase in soil bulk density and soil resistance to penetration. Factors in soil compaction due to vehicular traffic include: the amount of load, soil moisture content and the number of passes over the land. Soil compaction results in the formation of layers that can limit or delay (1) the aeration process; (2) root penetration and infiltration; (3) absorption capacity and soil water retention; (4) nutrient movement; (5) heat transfer, and (6) seedling emergency. At the same… More >

Zhang YG, HY Dai

Phyton-International Journal of Experimental Botany, Vol.80, pp. 119-125, 2011, DOI:10.32604/phyton.2011.80.119

Abstract The photosynthetic and morphological characteristics, and microstructure of roots and shoots, were studied between columnar apple and standard apple trees derived from the crosses of ‘Fuji’ × ‘Telamon’ and ‘Gala’ × ‘Telamon’. The results showed that chlorophyll A, chlorophyll B, the content of chlorophyll A+B, and leaf area index were higher in columnar apple trees than in standard apple trees. In a day cycle, the net photosynthetic (Pn) and transpiration rates (Tr) were higher in the columnar apple trees than in standard apple trees. The daily variations of Pn and Tr were of a double… More >

Clyde K Coelho, Cristobal Hiche, Aditi Chattopadhyay

Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 65-82, 2011, DOI:10.3970/sdhm.2011.007.065

Abstract Low velocity impacts on composite plates often create subsurface damage that is difficult to diagnose. Fiber Bragg grating (FBG) sensors can be used to detect subsurface damage in composite laminates due to low velocity impact. This paper focuses on the prediction of impact loading in composite structures as a function of time using a support vector regression approach. A time delay embedding feature extraction scheme is used since it can characterize the dynamics of the impact using the sensor signals. The novelty of this approach is that it can be applied on complex geometries and… More >

S.M.O. Tavares¹, S.M. Häusler², P.M. Baiz³, P.M.S.T. de Castro¹, P. Horst² , M.H. Aliabadi³

Structural Durability & Health Monitoring, Vol.7, No.3, pp. 191-210, 2011, DOI:10.3970/sdhm.2011.007.191

Abstract This article is the second part of a two parts paper which presents, compares and discusses the different crack growth simulation models which were introduced for fatigue crack growth assessment during the DaToN project. In the first part, different simulation approaches were applied to determine a calibration of the stress intensity factors as a function of the crack length for a two stiffeners panel with a central crack. Due to the residual stress field promoted by the different manufacturing processes, its influence was included in the numerical models to determine the stress intensity factors. In… More >

S. Atobe¹, H. Fukunaga¹, N. Hu²

CMC-Computers, Materials & Continua, Vol.26, No.1, pp. 67-90, 2011, DOI:10.3970/cmc.2011.026.067

Abstract This paper presents a method for identifying the location and force history of an impact force acting on CFRP structures such as laminated plates and stiffened panels. The identification method is an experimental one without using any analytical model of the structure. Here, experimental transfer matrices, which relate the impact force to the corresponding responses of PZT sensors, are used to identify the impact force. The transfer matrices are preliminarily constructed from the measured data obtained by impact tests with an impulse hammer. To identify the impact location, the arrival times of the flexural waves More >

Xiuqin Zhang¹, Simon Wang^2*, Yingshun Zhang³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.4, pp. 121-122, 2011, DOI:10.3970/icces.2011.017.121

Abstract A B-spline finite strip model is developed in the context of a layer-wise plate theory for analysing the geometrically non-linear transient response of laminated composite plates subjected to transverse low-velocity impact. To simplify the complicated contact analysis, a Hertz-type contact law has been incorporated into the finite strip (FS) model for accounting for the contact behaviour. The model includes the geometrical non-linearity through use of von Karman's non-linear strain-displacement relationship. The resulting non-linear dynamic problem is solved using the Newmark time-stepping scheme together with Newton-Raphson iteration. Several numerical applications are described and a close comparison More >

Liu Bingfei, Dui Guansuo, Zhu Yuping

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.3, pp. 73-74, 2011, DOI:10.3970/icces.2011.017.073

Abstract Several constitutive models with different yield functions for porous shape memory alloy (SMA) are compared with the experimental date. Different approaches such as upper bound theory and lower bound theory have been adopted and a new correction formula of the yield function is proposed in this work to study the behavior of porous SMAs. Numerical results are compared with the experimental date by Zhao et al (2005). It shows that the researches using upper bound and lower bound are nearly the same and the new correction formula is much closer to the experimental data than More >

Dr John Dear (Lead Author)

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.2, pp. 37-38, 2011, DOI:10.3970/icces.2011.017.037

Abstract This key-note lecture is a contribution to: ICCES’11 SPECIAL SYMPOSIUM ON MODERN EXPERIMENTAL METHODS IN MECHANICS, ENGINEERING, AND THE SCIENCES (Organizing Committee Co-Chairs: Fu-Pen Chiang (USA), YiIan Kang (China), Huimin Xie (China), Xiaoyuan He (China))
Presented, in this keynote lecture, are experimental data relating to composite sand wich materials subjected to different rates of loading including explosive blast. The composite sandwich materials are manufactured using a variety of different skin and core materials. Experimental results are described for quasi-static, high-rate and explosive blast loading using DIC to identify failures processes.
An important benefit of… More >

Qiao Hua, Wei-Qiu Chen, Qingda Yang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.2, pp. 37-38, 2011, DOI:10.3970/icces.2011.020.037

Abstract Predicting arbitrary delamination in laminar composites remains a significant numerical challenge in composite engineering [1,2]. Currently the major technical difficulty is to predict accurately when (at what load level) and where (in which interface) should delamination occur within a pristine composite laminates upon loading. Linear-elastic-fracture-mechanics (LEFM) based methods have limits because 1) requirement of known or assumed initial flaws of finite size, and 2) unknown crack-tip singularity functions for interfaces that bond non-orthogonal plies. Numerical tools based on LEFM such as virtual crack closure technique (VCCT) suffer from serious numerical problems including numerical instability and robustness.
… More >

Li Shan, Ming Cheng, Kaixin Liu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.3, pp. 87-88, 2011, DOI:10.3970/icces.2011.019.087

Abstract In the present paper, a combined scheme of discrete element method (DEM) and meshless method for numerical simulation of impact problems is proposed. Based on the basic principle of continuum mechanics, an axisymmetric DEM framework is estabilished for modeling the elastoplastic behavior of solid materials. A failure criterion is introduced to model the transformation from a continuum to a discontinuum. The friction force between contact elements is also considered after the failure appears. So our scheme can calculate not only the behavior of continuum and discontinuum, but also the transformation process from continuum to discontinuum. More >