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Test dummy for whole body4 (2)


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Test dummy for whole body4 (2)

  1. 1. Literature Review 1 Test Dummies for Human Whole Body Vibration Name Institution Date
  2. 2. Literature Review 2 Test Dummies for Human Whole Body Vibration Anthropomorphic test gadgets commonly referred to as “dummies” have been the most widely used devices for testing safety systems (David, Viano & Parenteau, 2012). Applied as subjects for evaluating the possible damages to human travelers in airplane, automobiles and marine aircraft, dummies have formed the subject for construction and development of safety gadgets in the travels industry (Mullin, 2007; Peters & Peters, 2002; Freeman, 2007). According to Freeman (2007) earlier dummies only focused on the determination of potential hazards or stresses associated with mechanical forces impacted on human beings during travelling. To him the design of these dummies approximated human kinematics with failure to focus on the stresses imposed on human beings (Freeman, 2007). The deficiency led to development of more biofidelity test dummies that are available commercially today. Peters & Peters (2002) also posit that the development of general purpose dummies between the years 1956 and 1963 did not effectively achieved the human kinematics desired. They stated that Mark 1 for instance, a 95th percentile dummy developed during the period attained the design of a typical human being. The assembly consisted of all parts that are observed in human skeleton. However, the joints of the ankle, elbow, knee and neck were too stiff hence calling for future adjustments to obtain a real representation of human being skeleton. In 1972, Dynamic Dan was developed as an analog approach for obtaining an improved version of the previous dummies. Willinger et al., (2005) states that the development process of this dummy put into consideration the flexible nature of human beings. The assembly corresponded to that of humans with the use of more improved materials to produce a more realistic dummy. In his study of whole body response to dynamic loads Van Niekerk et al., (1999) notes that Dynamic Dan was designed for aircraft ejection seat testing. They say that the
  3. 3. Literature Review 3 incorporation of a flexible joint through the use of springs and the use of fiberglass for bone composition, allow for effective determination of vertical vibration effect on humans. Michael et al., (2001) also supports this observation by pointing out that the inclusion of a ball socket as a representation of hip and shoulder joints allowed for universal movement that is a critical requirement on the determination of vertical impact on human body. However, Nicola, Luca, Fausto & Bruno (2010) argues that this dummy did not achieve all the requirements for its consideration in the development of safe and reliable ejection belts. They say that the dummy was only capable of determining the visible external impact of vertical vibration on human body without consideration of the possible cause of the observed damages (Nicola, Luca, Fausto & Bruno, 2010). They therefore suggested on the inclusion of joints capable of incorporating motion-limiting stops that when calibrated will provide the amount of energy absorbed. Research shows that this improvement have since been made with the introduction of adjustable friction dumping at all the joints for simulation of motion resistance from relaxation to rigidity that allowed for energy absorbed during the ejection process to be obtained (Willinger, Bourdet, Fischer & Le Gall, 2005). Supermorphic dummy developed after the aforementioned dummies formed the most sophisticated human structure imitation. Willinger, Bourdet, Fischer & Le Gall, (2005) argues that this is one of the most realistic dummies that were made after 1970 in the field of human imitation for hazardous forces. They noted that the full articulation of neck, head and limbs observed in this dummy allowed for it to assume any posture of human being. As such was reliable for the determination of potential effects of hazardous mechanical impacts on humans at whatever position (Willinger, Bourdet, Fischer & Le Gall, 2005). In addition, Arthur, Croft & Mathieu, (2007) posited that the incorporation of motion, pressure and vibration measurement
  4. 4. Literature Review 4 devices on the skeleton of the dummy made it more advanced compared his previous counterparts. For instance, the inclusion of potentiometers and accelerometers for motion and pressure monitoring allowed for evaluation of the value of potential forces that are likely to incur human damages. Research also shows that this dummy had a power supply source mounted on its head that allowed for independent measurements to be attained. As Nicola, Francesca &Tommaso (2010) notes, this was considered one of the most reliable dummies for ejection vibration testing. Regardless of the desirable designs of the dummy posited by various researchers Van Niekerk et al., (1999) however, argues that the design material adopted and the structure of the dummy were of much quality. In fact, they say that the dummy is of lower quality as compared to the previous developed ejection testing dummies. they base their arguments on the fragility of the design material that posses a chance of damages during the ejection process. According to Mullins (2007) various cases of dummy damages have been recorded in areas where the supermorphic dummy was adopted for testing. He suggested that unless the durable design materials are used in the development of the dummy, then the accuracy and reliability of the vibration data would not be possible. In his study on dummy design and testing he came to a conclusion that supermorphic dummy was too fragile and unreliable for airplane seat ejection quality testing (Mullins, 2007). With further advancement on the dummy design, Hybrid III consisting of large male and small female dummies was developed. According to literature, this dummy had the most improved shoulders, neck, spine and knees as compared to the previous dummies (Nicola, Luca, Fausto & Bruno, 2010). Further advancement was made on this dummy by General Motors that allowed for more extensive and transducers data to be obtained during the testing procedures. As posited by Michael et al., (2001) hybrid III dummy is developed in a way that it imitates the real
  5. 5. Literature Review 5 human body structure. Literature shows that the dummy was developed by the use of human skeleton structures as opposed to the artificial materials adopted in the previous dummies. As indicated by Willinger, Bourdet, Fischer & Le Gall, (2005) the dummy allowed for reliable and quantified data to be obtained from the vibration impact testing. Research conducted by Freeman, (2007) on the dummy design and anatomy indicated that this dummy had a detailed description of the main human bone structure, the density of the bones used correspondent to that of real human being. In addition, flexibility of the dummy joints was assured by the incorporation of flexible and spherical connecters allowing for universal movement (Freeman, 2007). Over the years, hybrid dummy III have been improving over the years (Mullins, 2007). Today, this dummy are developed with high level of biofedility and consisted of quantification devices that allowed for reliability and validity of the vibration impact data quantification. It is evident from literature that this dummy is available commercially and still adopted in automobile testing (Nicola, Luca, Fausto & Bruno, 2010). However, dummy constructions projects team and organizations are still enhancing the quality and structure of the hybrid III type dummy for effectiveness and reliability during the testing process. From literature, it is evident that hybrid II and hybrid III are the most adopted dummies for aero craft testing. According to, Nicola, Luca, Fausto & Bruno (2010), these dummies are designed to determine the probable effects occurring on aircraft seat in case of survivable plane crash. As indicated by Freeman, 2007 these dummies have flexible appendages that allow them adapt to the sitting posture of human while in plane. The inclusion of a full imitation of human weight and density makes them effective in the quantification of the possible outcome of hazardous impact on humans (Freeman, 2007). Mullins, (2007) posits that these dummies have contributed to the development of safety ejection devices as well as air plane seats for travelers
  6. 6. Literature Review 6 for purposes of security. As indicated by Nicola, Luca, Fausto & Bruno, (2010) the dummies have also contributed to the vast knowledge experienced in the development of cars and tractors that are available today. Minimal research has been conducted on the safety dummies applicable in marine travelling. According to Willinger et al., 2005) increase in number of marine ship and aircraft calls for development of suitable seats and suspension devices that will provide some safety in case of the accidents. Nicola, Luca, Fausto & Bruno (2010) also argues that the vibration of sea waves are critical to human travelers and should be managed effectively to achieve vast levels of safety. Research on the design of suspension seats indicate that they require non-linear operation such that their performance can be determined by prevailing conditions (Huang, Yeh, Wu & Dai, 2007). The continuity of vibration due to the moving sea waves makes durability a prerequisite in the development of suspension seats (Huang, Yeh, Wu & Dai, 2007). Moreover, Arthur, Croft & Mathieu, (2007) argues that suspension seat manufactures should focus on the design and dynamic nature of potential hazards in the formulation of suspension seat dummies. Durability, high biofidelity, flexibility and human posture imitation are some of the fundamental aspects of design that should be put in place prior to the assembly of the dummy skeleton for high efficiency suspension seat dummy (Arthur, Croft & Mathieu, 2007). Advantages and Disadvantages of the Test Dummies From the review of literature it is evident that no studies or researchers have established generally applicable merits or demerits of test dummies (Willinger et al., 2005). However, particularistic significances have been posited by a wide range of studies testing distinct test dummies contexts (Willinger et al. 2005; Freeman, 2007; Arthur, Croft & Mathieu, 2007; Nicola, Francesca & Tommaso, 2010). Mullins, (2007) while studying the Dynamic Dan dummy noted
  7. 7. Literature Review 7 that while this dummy had the advantage of universal movement of appendages that could ensure determination of the mechanical impact as crash or vibration, the quantification of the mechanical impact remained indeterminable since it lacked the devices that could measure pressure and motion leaving a measurement gap. Although other studies (Van Niekerk et al., 1999; Willinger et al., 2005) showed that this disadvantage of quantification could not be of a great consideration in the practical application of this impacts on humans, David, Viano & Parenteau, (2012) warned that the failure to measure exact synergic impact of the vibration or crash could result in a false assumption of positive results. As an improvement to the dynamic Dan dummy, researchers sort to solve this quantification dilemma (Mullins, 2007). The result was the supermorphic dummy which took into account all the measurement parameters which could allow the quantification of the impacts (crash or vibration). Moreover, this dummy had more improved and flexible appendages compared its predecessor Dynamic Dan (Arthur, Croft & Mathieu, 2007). However, two fundamental disadvantages still ruined its fruitfulness in providing completely or near realistic results. As Freeman, (2007) later noted, this dummy did not splendidly embody the human body in terms of weight and body part flexibility. In addition, the supermorphic dummy was too fragile, taking into consideration that it was for the testing of ejection devices’ vertical force impacts, to an extent that even the quantification considered as their advantage could not be measured on the course of the testing (Freeman, 2007). Later development of dummies such as hybrid II and hybrid III model brought several advantages to the safety testing of mechanical objects (David, Viano & Parenteau, 2012). According to Peters & Peters (2002) hybrid III was more advanced and provided full representation of human biofidelity. The inclusion of motion, vibration and pressure measuring
  8. 8. Literature Review 8 devices in this dummy allowed for quantification of safety data applicable to automobile and plane safety device construction. Research also shows that in addition to the flexible nature and the exact imitation of human in terms of weight and posture of the dummy allow for achievement of practicality of the possible impact and damages of hazardous forces on human beings (Mullins, 2007; Freeman, 2007). Literature shows that durability and flexibility are some 0f the fundamentals aspect of design that must be incorporated in the development of the dummies (Willinger, Bourdet, Fischer & Le Gall, 2005). According to David, Viano & Parenteau, (2012) high weight dummies are more applicable in air plane and automobile as compared to marine aircrafts. The need for suspension as opposed to movement along gravity requires the adoption of a light weight device that will effect floatation. Justin, (2007) noted that automobile and airplane dummies requires additional advancement and improvement to provide informed decision and data on the effects of vibration on humans travelers in the sea. Further research also indicated that previous dummies had a disadvantage of focusing on the typical shape and posture of human being with no regards to the required shape during movements in water. According to Mullins, (2007) a major disadvantage is also obtained in the quantification of the motion, vibration and pressure data due to the negative influence of water on measurement devices such as potentiometers and accelerometer. As much as the dummies discussed were of benefits to the safety device testing systems, literature shows that each and every dummy adopted had cert6ain drawbacks requiring amendments for perfection of the testing system (David, Viano & Parenteau, 2012). Nicola, Luca, Fausto & Bruno (2010) indicated that the achievement of the biofedility by the recent and current dummies is not a final indication of their success in the safety device testing systems. He
  9. 9. Literature Review 9 argues that adjustments are necessary for the dummies to fit the test requirement for efficient and reliable data to be obtained.
  10. 10. Literature Review 10 References Arthur, C., Croft, & Mathieu, M (2007).The RID2 biofidelic rear impact dummy: A pilot study using human subjects in low speed rear impact full scale crash tests Original Research Article. Accident Analysis & Prevention, 39 (2) pp.340-346 David, C., Viano, S. Parenteau, R (2012).Influence of standing or seated pelvis on dummy responses in rear impacts Original Research Article. Accident Analysis & Prevention, 45, pp. 423-431 Freeman, M 2007, ‘Crash Test Dummy’, The New Scientist, vol.194, no.2609, pp.22-23. Huang, T., Yeh, C., Wu, C., & Dai, Y 2007. ‘Impact Analysis and Simulation of Crash Test Dummy Ribcage Mechanism’, Journal of Biomechanics, vol.40, pp.656-656. Justin, M (2007).The human crash test dummy. New Scientist, 194 (2602), pp. 50-51 Michael, J., Rory, A., Thomas, J., Michael, L., & Shirley G (2001). Kinematic comparison of Hybrid II test dummy to wheelchair user Original Research Article. Medical Engineering & Physics, 23(4) pp. 239-247 Mullins, J 2007. ‘The Human Crash Test Dummy’, The New Scientist, vol.194, no.2602, pp.50- 51. Narayan, Y & Frank A (2005). Responses of side impact dummies in sled tests Original Research Article. Accident Analysis & Prevention, 37(3), pp. 495-503 Nicola, P., Francesca, C &Tommaso, M (2010).Full scale impact testing of ski safety barriers using an instrumented anthropomorphic dummy Original Research Article. Procedia Engineering, 2 (2), pp. 2593-2598
  11. 11. Literature Review 11 Nicola, P., Luca, T., Fausto, P & Bruno, A (2010).Development of an instrumented anthropomorphic dummy for the study of impacts and falls in skiing Original Research Article. Procedia Engineering, 2(2), pp. 2587-2592 Peters, G. A., & Peters, B. J 2002. Automotive vehicle safety.Taylor & Francis. London. Van Niekerk, J.L., Heyns, P.S., Heyns, M., and Hassall, J.R 1999. ‘Human vibration levels in the South African mining industry’. Kingdom Meeting on Human Response to Vibration, vol. 4, no. 21 Willinger, R., Bourdet, N., Fischer, R., & Legall, F 2005. ‘Modal Analysis of the Human Neck in Vivo as A Criterion for Crash Test Dummy Evaluation’, Journal of Sound and Vibration, vol.12, p. 13.