A final study that was explored focused on the importance of finite element analysis for analyzing the effects of composite patching on CCT. According to [S3], FE analysis is helpful because it leads to a direct computation of both the SIF and stress-distribution field. This study used 2024-T3 aluminum with a glass and epoxy composite patch. Cyclic stress was applied to patched and unpatched aluminum specimens, and the Mindlin FE Approach was used to analyze the resulting data. Results showed that crack growth was greatly reduced in the patched specimens, although crack growth will accelerate rapidly if it manages to extend beyond the patch. Interestingly, these experimental results showed that dis-bonding of the patch occurs following crack
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For instance, composites, although more prominent and researched than ever, don’t have as many reliable testing methods as other materials, such as metals. This makes it difficult to do proper safety checks on composite airplane components. Damage of composites is also not observable by the naked eye and is easily missed. In order to actually determine if a composite’s structure has been compromised, further testing and equipment is required, which makes the whole situation easy to overlook or ignore. Human error and material selection are two other areas that pose significant threats. Although composite patching is more straightforward than traditional mechanical patching, there are still a number of steps involved in which the user applying the patch can make a mistake. This is compounded by the fact that the world of composite patching is ever-changing, leading to a lack of standardized, repeatable practices and techniques that workers can follow. Care must be taken when performing the patch application procedure, and this goes hand in hand with material selection. If the user selects a composite that has not been properly vetted for the job, the least that will have to be done is replacement of the current composite. Oftentimes, the first composite is then mixed with a different composite in order to satisfy the mechanical properties that are needed. At worst, the original composite’s inadequacies go unchecked, and it is applied, leading to potential disaster.
For instance, composites, although more prominent and researched than ever, don’t have as many reliable testing methods as other materials, such as metals. This makes it difficult to do proper safety checks on composite airplane components. Damage of composites is also not observable by the naked eye and is easily missed. In order to actually determine if a composite’s structure has been compromised, further testing and equipment is required, which makes the whole situation easy to overlook or ignore. Human error and material selection are two other areas that pose significant threats. Although composite patching is more straightforward than traditional mechanical patching, there are still a number of steps involved in which the user applying the patch can make a mistake. This is compounded by the fact that the world of composite patching is ever-changing, leading to a lack of standardized, repeatable practices and techniques that workers can follow. Care must be taken when performing the patch application procedure, and this goes hand in hand with material selection. If the user selects a composite that has not been properly vetted for the job, the least that will have to be done is replacement of the current composite. Oftentimes, the first composite is then mixed with a different composite in order to satisfy the mechanical properties that are needed. At worst, the original composite’s inadequacies go unchecked, and it is applied, leading to potential disaster.