CPA Help Pages
				Help for Aspect Ratio
		Aspect Ratio: The aspect ratio determines the efficiency of the load transfer from the matrix to the fiber. The larger the aspect ratio, the more efficient is the load transfer. In most applications, the reinforcement phase (fibers and fillers) can be idealized as an ellipsoidal inclusion. The aspect ratio is therefore defined as the ratio to major or minor axis or, alternatively, the effective length to diameter of the inclusion. The range of aspect ratio for various types of reinforcements are summarized below:
		This definition is most appropriate for single filament reinforcement which are characteristic of injection and transfer molded compounds. In sheet molding compounds, however, individual filaments agglomerate into coherent bundles. At high volume fractions, contact and compaction of the rovings may produce marked "swirling." In both cases, the aspect ratio is defined as an effective length to fiber bundle diameters. The effective length is defined by partitioning the microstructure into domains exhibiting parallel filaments. Prior to detailed examination of the microstructure, the user should employ the program to investigate the sensitivity of the thermoelastic properties over a realistic range of aspect ratios. The influence of aspect ratio on some of the predicted properties may not be significant. In the event that the inclusions exhibit a size distribution, the aspect ratio entered into the program should correspond to the root-mean-square, average of the effective aspect ratio distribution.