Qiaoyang Zhang¹, Zhiyao Liang^1,*, Zhiping Cai²

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 457-471, 2019, DOI:10.32604/cmc.2019.03758

Abstract Wearable devices are becoming more popular in our daily life. They are usually used to monitor health status, track fitness data, or even do medical tests, etc. Since the wearable devices can obtain a lot of personal data, their security issues are very important. Motivated by the consideration that the current pairing mechanisms of Bluetooth Low Energy (BLE) are commonly impractical or insecure for many BLE based wearable devices nowadays, we design and implement a security framework in order to protect the communication between these devices. The security framework is a supplement to the Bluetooth… More >

Tongyan Yue^1,2, Magd Abdel Wahab^3,4,*

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 405-432, 2019, DOI:10.32604/cmc.2019.04253

Abstract Fretting wear is a material damage in contact surfaces due to micro relative displacement between them. It causes some general problems in industrial applications, such as loosening of fasteners or sticking in components supposed to move relative to each other. Fretting wear is a complicated problem involving material properties of tribo-system and working conditions of them. Due to these various factors, researchers have studied the process of fretting wear by experiments and numerical modelling methods. This paper reviews recent literature on the numerical modelling method of fretting wear. After a briefly introduction on the mechanism More >

Yanwei Li¹, Yugui Li¹, Peisheng Han¹, Shun Wang¹, Zhengyi Jiang^1,2, Xiaogang Wang^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.1, pp. 109-123, 2018, DOI:10.31614/cmes.2018.04077

Abstract This study developed a new technology for preparing high-chromium cast iron (HCCI)/low-carbon steel (LCS) wear-resistant composite plates by hot rolling at a 1050 °C and a rolling speed of 0.2 m/s. The effects of different rolling reductions (30%, 45%, and 60%) on the microstructure (interface and HCCI layer) and mechanical properties (bonding strength, hardness, and wear resistance) of the composite plate were studied. SEM images showed that when the reduction was increased, no impurities and interlayers were found between the microscopic interfaces after hot rolling, and the bonding interface exhibited a wave-like shape. EDS analysis… More >

Isabel Patrícia Fernandes¹, Mariana Barbosa¹, Joana Soares Amaral², Vera Pinto³, José Luís Rodrigues³, Maria José Ferreira³, Maria Filomena Barreiro^1*

Journal of Renewable Materials, Vol.4, No.1, pp. 47-56, 2016, DOI:10.7569/JRM.2015.634126

Abstract Among the wide variety of materials employed in the manufacture of shoes, thermoplastic polyurethanes (TPUs) are one of the most widely used. Given its widespread use, and associated waste management problems, the development of more biodegradable and evironmentally compatible solutions is needed. In this work, a polyester-based TPU used in the footwear industry for outsoles production was modifi ed by compounding with lignin, starch and cellulose at content of 4% (w/w). The biodegradability was evaluated by using agar plate tests with the fungi Aspergillus niger ATCC16404, the Gram-negative bacteria Pseudomonas aeruginosa ATCC9027 and an association More >

L. Rodríguez-Tembleque¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 183-210, 2014, DOI:10.3970/cmes.2014.102.183

Abstract This work presents new contact constitutive laws for friction and wear modelling in fiber-reinforced plastics (FRP). These laws are incorporated to a numerical methodology which allows us to solve the contact problem taking into account the anisotropic tribological properties on the interfaces. This formulation uses the Boundary Element Method for computing the elastic influence coefficients. Furthermore, the formulation considers micromechanical models for FRP that also makes it possible to take into account the fiber orientation relative to the sliding direction, the fiber volume fraction, the aspect ratio of fibers, or the fiber arrangement. The proposed More >

Y.J. Chen¹, N. Huber^1,2

CMC-Computers, Materials & Continua, Vol.29, No.1, pp. 1-14, 2012, DOI:10.3970/cmc.2012.029.001

Abstract Gear transmission is important in engineering due to its high efficiency in transferring both power and motion. As a surface phenomenon, wear may change the gear geometry, cause a non-uniform gear rate and increase dynamic effects, all of which can lead to reduced efficiency and even severe tooth failure. In numerical predictions of wear, the conventional method, where the contact pressure over the slip distance is integrated, will cause a computation bottle-neck. To obtain an accurate integration of the wear within the small, fast moving contact area, the finite element model needs to be meshed… More >

L. Rodríguez-Tembleque¹, R. Abascal¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.2, pp. 127-156, 2012, DOI:10.3970/cmes.2012.087.127

Abstract A boundary element based formulation is proposed to simulate 3D fretting wear under gross-sliding and partial slip conditions, assuming anisotropic friction and wear laws. Contact problem is based on an Augmented Lagrangian formulation, and restrictions fulfilment is established by a set of projection functions. The boundary element method reveals to be a very suitable numerical method for this kind of problems, where the degrees of freedom involved are those on the solids surfaces, and a very good approximation on contact tractions is obtained with a low number of elements. The present boundary element anisotropic fretting More >

Metin Kök^1,2, Erdogan Kanca³

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 213-236, 2010, DOI:10.3970/cmc.2010.018.213

Abstract In this investigation, a new model was developed to predict the wear rate of Al2O3 particle-reinforced aluminum alloy composites by Genetic Expression Programming (GEP). The training and testing data sets were obtained from the well established abrasive wear test results. The volume fraction of particle, particle size of reinforcement, abrasive grain size and sliding distance were used as independent input variables, while wear rate (WR) as dependent output variable. Different models for wear rate were predicted on the basis of training data set using genetic programming and accuracy of the best model was proved with More >

Chen Y J^1,2, Huber N^2,3

CMC-Computers, Materials & Continua, Vol.16, No.1, pp. 1-24, 2010, DOI:10.3970/cmc.2010.016.001

Abstract An efficient wear integration algorithm is crucial for the simulation of wear in complex transient contact situations. By rewriting Archard's wear law for two dimensional problems, the wear integration can be replaced by the total contact force. This avoids highly resolved simulations in time and space, so that the proposed method allows a significant acceleration of wear simulations. All quantities, including the average contact velocity, slip rate and total contact force, which are required for the pressure-force transformation, can be determined from geometric and motion analysis, or alternatively, from Finite Element simulations. The proposed CForce More >

Peter J. Ireman, Anders Klarbring¹, Niclas Strömberg

CMES-Computer Modeling in Engineering & Sciences, Vol.52, No.2, pp. 125-158, 2009, DOI:10.3970/cmes.2009.052.125

Abstract In this paper finite element approaches for fretting fatigue are proposed on the basis of a non-local model of continuum damage coupled to friction and wear. The model is formulated in the frame-work of a standard material. In a previous paper this was done in the spirit of Maugin, where an extra entropy flux is introduced in the second law in order to include the gradient of the internal variable in a proper manner. In this paper we follow instead the ideas of Frémond and others, where this extra entropy flux is no longer needed,… More >