CAI strength

Fig. 8.8. Correlation of residual compression-after-impact (CAI) strength with resin flexural strain to...

Probably the most serious case, and the most discussed, is that of B VID and its effect on CAI strength. It is discussed by literally hundreds of studies [1,2]. Several types of damage, initiating failure in compression, are sketched in Figure 9.5. 

These results imply that both CAI strength and the fatigue Unfit of impact-damaged laminates will be dependent on the Gic static toughness values for comparable impact damage levels. 

Figure 6.53 Effect of the impact energy on the CAI strength of the sandwich structure. Source [47] Reproduced with permission from lOP Publishing...

Tang, Y., Ye, L., Zhang, Z., Friedrich, K., 2013. Interlaminar fracture toughness and CAI strength of fibre-reinforced composites with nanoparticles—a review. Composites Science and Technology 86, 26—37. 

A. Jones Yes, I didn t show all the data. Most of the data is from the literature. Polystyrene data and polyisobutylene data at two field strengths can be accounted for by these lattice models based upon the three bond jump. Some recent data by Dr. Bovey on the polybutene was more difficult to fit with regard to the frequency dependence. (F. C. Schilling, R. E. Cais and F. A. Bovey, Macromolecules ]A, 325 (19T8).) Frequency dependent data I think is important information to acquire when trying to understand the dynamics. 

As can be seen from the results, the composite formed from monomer/-polymer 114a with Celion G30-500 8HS fabric exhibited excellent mechanical properties [28], To a first approximation it would appear that the inherent fracture toughness of the matrix resin has been carried over to the composite panels. The CAI (compressive strength after impact) and OHC (open hole compression) tests are a direct measurements of the toughness of the composite part, the value of 332 MPa for the CAI compares very favorably to the value of 300 MPa typical for the thermoplastic composites. The OHC values under hot-wet test conditions would seem to indicate that the composite has very good retention of its mechanical properties at both 177°C and 203 °C. 

Lest the above discussion of the WB model for rims sound too negative, there are many strengths of their model. Rims must have formed in multiple stages, and the general trace element enrichment in rims over the host CAIs is an important constraint that must be addressed. It is also likely that the multilayered aspect must result from solid-state processes involving diffusion (eg., see MacPherson et al, 1981). 

OHT open-hole tensile OHC open-hole compression CAI compression strength after impact EDS edge delamination strength. (Adapted from Table 4 in Pilato, L.A. Michno, M.J. Advanced Composite Materials Springer-Verlag Berlin, 1994 118.)... 

Chemical agent identification sets (CAIS), which were also disposed of by burial and are frequently found, are also NSCWM.4 CAIS are kits consisting of small vials or ampules of diluted or full-strength chemical agents that were used by the U.S. Army for training troops to recognize the odor and the effects of CWM. 

Balkrishnan et al. suggested that, even though the tortuosity in the zeolite channels is increased, the observed higher selectivity toward Cj-C olefins in the methanol conversion on P-modified ZSM-5 is due more to a change in the acidity than to any steric effect. According to Cai et al., ° phosphorus affects both Bronsted and Lewis sites of various acid strength. As a result, an increased ethylene selectivity was attained. 

The relationship between the impact properties and morphology in ICP has been studied extensively. For example. Tan et al. (4) and Cai et al. (5) examined the effect of morphology on the impact strength using ICP samples with similar ethylene content, molecular weight, and molecular weight distribution. A typical SEM micrograph of fractured surface ICP specimens after the impact test at — 20°C is shown in Fig. 8.3. 

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