RTRI ratio

The load ratio is sometimes difficult to be applied for in-situ monitoring, because the maximum stress experienced is not readily estimated. Instead, the RTRI ratio has been proposed (Luo et al. 2002). 

The RTRI ratio is defined as in the following procedure the onset of AE activity is estimated from any measured parameters of stress/load, strain/deformation and so forth, and then the ratio is obtained as the ratio of the parameter s value corresponding to the onset of the AE activity to the maximum value (or peak value) during the whole inspection period instead of the maximum stress of which the structure has experienced. 

As given in Chapter 4, combination of the calm ratio and the RTRI ratio is known to be effective to estimate the stmctural damage in railway struc-... 

Fig. 14.22. Damage quantification with the calm ratio and the RTRI values. Dotted lines show the criteria for damage qualification. Labels H, 1 and M show heavy damage (H), intermediate damage (1) and minor damage (M), respectively.

Table 4 gives some experimentally determined yalucs of the radius of interaction R as compared with the radius of the primary particles, ft, for rapid coagulations. With a London-Van Der Waals constant of 1 or 2 R is expected to be 3 or 4 Experimentally the ratio Rtri is found between 2 and 3 showing that there is an attraction with a range of about one particle radius though perhaps somewhat smaller than the calculated one. 

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