{'fraction_non_alphanumeric': 0.014590932777488274, 'fraction_numerical': 0.008858780614903595, 'mean_word_length': 5.254071661237785, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Design of HIC compliant aircraft bulkheads and cabin class divider panels

Abstract The need for head injury protection has been addressed with the inclusion of the Head Injury Criteria, (HIC), in the dynamic seat certification requirements specified in paragraph 562 of the Federal Aviation Regulations Part 23, 25, 27, and 29. Compliance with the HIC poses a significant problem for many segments of the aircraft industry. The certification requires engineers to demonstrate that a head strike into any one of several cabin furnishing complies with a HIC threshold of 1000. The problem encountered in the certification of 16G seats, referred to as the front row HIC problem, occurs for seats located behind bulkheads and cabin class dividers. These structures are typically stiff and hence produce unacceptably large HIC values. This paper deals with the design and fabrication of a bulkhead for HIC attenuation, meeting the industry's appearance and aesthetic requirements as well. This paper addresses the study conducted on various honeycomb materials for HIC attenuation. MADYMO biodynamic simulations, supported by simple quasi-static tests, were developed for the design of HIC compliant bulkheads which effectively attenuated HIC below the injury levels. The validated MADYMO models were utilized for a parametric study of the effects of stiffness and strength of the bulkhead on HIC levels and to develop design heuristics for the fabrication of HIC compliant bulkheads. New bulkhead designs and materials were derived, statically tested for the loaddeflection properties and the results were compared with design curves. The compliance of the new bulkheads for HIC was then assessed by conducting full-scale dynamic sled tests on these structures at both small and large seat setback distances. A detailed methodology for the design and development of HIC compliant bulkheads is also explained in this paper.