The objective of the book is to present the practical fundamentals for the analysis of composites. For the most part, these aspects are relatively consistent among companies (though each company has differences in their approaches). Using the presented principles in the book, the reader can then develop specific methods for higher-level structures such as fuselage frames, actual skin-stringer configurations, etc. Test data is an integral aspect to developing a validated analysis method for final analysis, so the reader must have relevant test data from these higher-level configurations (function of the company resources and other factors). See Section 2.4 of the book (also in the book sample).

As discussed in Section 2.4 (and shown in Figure 2.2), (see the sample), a validated analysis method requires test data and is inherently semi-empirical. This is especially true for the static analysis of composites (metals usually require less test data for static analysis). “Pure” analytical solutions for composites do not currently exist, espeically for damage scenarios.

For higher level structures (fuselage frames, actual skin-stringer configurations, etc.), the approaches between companies start to diverge to a greater degree compared to the lower level aspects of analysis (details such as notched strength, joint analysis, basic stability analysis, etc.). This is because of the increased number of variables such as the available test data, fidelity of the analysis, history of use, level of conservatism, specific configurations (i.e. mechanically fastened versus cocured skin-stringer configurations), manufacturing methods and available tools, type of material (glass versus carbon versus hybrids), unique failure modes for composites, subtle but important design distinctions, etc. For higher level structures, semi-empirical correction factors are required to validate the approach (for the aircraft industry requirements). This is especially true for the damage tolerance requirements (various damage categories) since there is no way to predict the residual strength for some of these scenarios via analytical solutions. Since each company may have a different testing approach, test resources, design criteria, and analytical strategies, the analysis methods (and associated correction factors) are unique to the available resources and the specific configuration. Attempting to present specific “cook book” methods for higher level structures has the potential to be limiting, misleading, and in conflict with each company’s strategy.

That said, it is still possible to discuss higher level structures in a general manner. For example, there are typical checks that often size each type of structure and each structure has unique aspects to consider. Some of these aspects are discussed in the book and a later edition may further expand upon this. However, for the reasons previously discussed, later editions are not expected to provide “cook book” solutions for higher level aircraft composite structures.