النتائج (
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Fiber reinforced composite materials have been increasingly used in various structural components in the aerospace,marine, automotive and wind energy sectors. Although manufacturing and investment costs of composite materials are high when compared to conventional materials (primarily metals), their higher strength per unit weight and fewer required machining and fastening operations increase the popularity of composite materials day by day. The direction-dependent mechanical properties of composite materials can also be advantageous in some applications where strength is only required in a specific direction.In the processing of composite materials, the final shape of the composite parts is not the same as the mould shape after the process due to process induced distortions. The basic reason behind the distortion is the process induced residual stresses occurring during the manufacturing process.The nonuniform distribution of residual stresses inside the composite materials results in deformation, matrix cracking, and even delamination. These distortions are represented by spring-in in curved parts and by warpage in flat parts. Problems occur during and after the assembly of parts due to poor contact between mating surfaces unless the magnitude of these distortions are predicted within the tolerances. The assembly of aerostructures especially rigid structures requires matching of smaller sub-components like shims in the assembly phase.Using the sub-components causes the assembly of composite structures to remain a labor-intensive task. On the manufacturing floor, a trial and error approach is preferred to compensate geometrical variations like spring-in angle, but this method is very expensive and time consuming when manufacturing of large components. If the distortions are predicted closely in advance, the investment to the trial and error modification and labor-intensive task during assembly phase can be prevented.
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