By a News Reporter-Staff News Editor at Journal of Technology -- Data detailed on Solids Research have been presented. According to news reporting originating in Pisa, Italy, by VerticalNews journalists, research stated, "The paper presents a mechanical model for predicting the cohesive failure of a periodic array of integrated circuit (IC) chips adhesively bonded to a stretched substrate. A unit cell of the layered structure consisting of the IC chips, adhesive layer, and substrate is modeled as an assembly of two elastic Timoshenko beams, representing the chip and substrate, connected by an elastic interface, representing the adhesive."
The news reporters obtained a quote from the research from the University of Pisa, "Accordingly, the stresses and energy release rate (ERR) in the adhesive layer - responsible for the premature cracking of the adhesive and debonding of the IC chips - are identified with the corresponding quantities computed for the elastic interface. Expressions for the adhesive stresses and ERR are given in terms of geometrical dimensions and material properties, combined with integration constants obtained numerically via the multi-segment analysis method. For comparison, the stresses in the adhesive are also computed based on a finite element model, and the ERR is evaluated using the virtual crack-closure technique (VCCT). The analytical predictions and numerical results match fairly well, considering the effects of key factors, such as the distance between adjacent chips, the chip size, the material properties of adhesive and substrate. The interaction between the chips is shown to have relevant effects on the adhesive stresses."
According to the news reporters, the research concluded: "In particular, only the mode II contributes to the ERR which increases with the ratio of the chip size to the distance between the chips and with the compliance of the adhesive and substrate layers."
For more information on this research see: Cohesive failure analysis of an array of IC chips bonded to a stretched substrate. International Journal of Solids and Structures, 2013;50(22-23):3528-3538. International Journal of Solids and Structures can be contacted at: Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England. (Elsevier - www.elsevier.com; International Journal of Solids and Structures - www.elsevier.com/wps/product/cws_home/297)
Our news correspondents report that additional information may be obtained by contacting Z.X. Liu, University of Pisa, Dept. of Civil & Ind Engn, I-56126 Pisa, Italy. Additional authors for this research include P.S. Valvo, Y.A. Huang and Z.P. Yin.
Keywords for this news article include: Pisa, Italy, Europe, Solids Research
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