13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- 3.2 Results and Discussion With regard to the melting propagation of mesh segment, the variation of melting current Im and mesh resistance are shown in Fig. 4a and Fig. 4b. Note that the mesh resistance is the resistance between two mesh nodes where the external current is input and output (i.e., node (0, 0) and node (0, 9)), respectively. Two local parts (c) and (d) in Fig. 4a are enlarged in Fig. 4c and Fig.4d, respectively. In Fig. 4a and Fig. 4c, it is found that when the input current increases up to 0.225mA, the maximum temperature in one mesh segment reaches the melting point of Ag nanowire making the start point of the melting of mesh. For the following melting of the second mesh segment, the melting current decreases to the value of 0.217mA. With the melting propagation of mesh segment, the variation of melting current and voltage shows the repetition of three different trends as marked with arrows in Fig. 4c and Fig. 4d: (I) decrease of both melting current and voltage; (II) increase of both melting current and voltage; (III) decrease of melting current but increase of melting voltage. Finally, the melting of last mesh segment makes the open circuit of the mesh as shown in Fig. 4a. Here, the number of broken mesh segments nb corresponding to the open circuit of mesh is only 89, which is about one half of the number of the overall mesh segments (i.e., 180) in the intact Ag nanowire mesh. Generally, the nanowire mesh during the whole melting process in this case keeps symmetric, in which the exception is attributed to the minor error during the numerical simulation. On the other hand, the mesh resistance in Fig. 4b increases with the melting propagation of mesh segment, which is independent of the trend of melting current. Fig. 4 Numerical melting of an Ag nanowire mesh structure
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