Vertical Drop Test Research Articles

YS-11型機胴体構造の落下衝撃試験（その1）

The Structures and Materials Research Center of the National Aerospace Laboratory of Japan (NAL) and Kawasaki Heavy Industories, Ltd. (KHI) conducted a vertical drop test of a fuselage section cut from a NAMIC YS-11 transport airplane at NAL vertical drop test facility in December 2001. The main objectives of this program were to obtain background data for aircraft cabin safety by drop test of a full-scale fuselage section and to develop computational method for crash simulation. The test article including seats and anthropomorphic test dummies was dropped to a rigid impact surface at a velocity of 6.1 m/s (20 ft/s). The test condition and result were considered to be severe but potentially survivable. A finite element model of this test article was also developed using the explicit nonlinear transient-dynamic analysis code, LS-DYNA3D. An outline of analytical method and comparison of analysis result with drop test data are presented in this paper.

A modern aerospace modeling approach for evaluation of aircraft fuselage crashworthiness

A 9 [m/s], (30-ft/s) vertical drop test of a fuselage section of a Boeing 737 aircraft was conducted at the FAA William J. Hughes Technical Center in Atlantic City, NJ. Test was performed to evaluate the structural integrity of a conformable auxiliary fuel tank mounted beneath the floor and to determine its effect on the impact response of the airframe structure. The objective of the test was to determine the interaction between a typical transport aircraft fuselage, particularly its floor structure, and a conformable auxiliary fuel tank under severe, but survivable, impact conditions. The fuel tank used in this test is representative of tanks being installed in narrow-body transport aircrafts. The 3 [m], (10-foot) airframe section from a Boeing 737-200 aircraft was dropped from a height of 4.27 [m], (14-feet) generating a vertical impact velocity of 9 [m/s], (30-ft/s). The airframe test section weight of 3,982.5 [kg], (8780-lb) simulated the load density at the maximum takeoff weight condition. The weight included cabin seats, dummy occupants, and simulated fuel in the 1,892.71 liters, (500-gallon) fuel tank. Structural response data were obtained during the impact from instrumentation installed on the fuselage structure, floor structure, and the fuel tank. The fuselage test section sustained severe damage after the test. Portions of the cabin floor were damaged due to the impact with the auxiliary fuel tank located in the cargo compartment. Portions of the fuselage bottom were crushed by approximately 66 [cm], (26-in). The bottom of the fuel tank was punctured in numerous locations causing fuel to leak out. The strength and rigidity of the fuel tank limited the inherent ability of the fuselage structure to absorb energy crushing during the impact. The test data were used to compare with a finite element simulation of the fuselage structure and to gain a better understanding of the impact physics through analytical/experimental correlation. To perform this simulation, a full-scale 3-dimensional finite element model of the fuselage section was developed using the explicit, nonlinear 3-D Finite Element code, LS-DYNA. The emphasis of the simulation was to determine the structural deformation and floor-level acceleration responses obtained from the drop test of the B737 fuselage section with the auxiliary fuel tank.

YS-11型機胴体構造の落下衝撃試験（その2）

The Structures and Materials Research Center of the National Aerospace Laboratory of Japan (NAL) and Kawasaki Heavy Industries, Ltd. (KHI) conducted the 2nd vertical drop test of a fuselage section cut from a NAMC YS-11 transport airplane in July 2002. The main objective of this test program was to obtain background data for aircraft cabin safety by drop test of a full-scale fuselage section and to develop computational tool for crash simulation of aircraft fuselage structure. The test article including seats and anthropomorphic test dummies was dropped to a rigid impact surface by free-fall method at a velocity of 7.6m/s (25ft/s). The impact environment and the resultant response of the fuselage structure and the passenger dummies were considered to be severe but potentially survivable. A description of the results of the 1st drop test and the 2nd drop test is presented in this paper.

816 高性能緩衝・シール機能を有する輸送・貯蔵キャスクの開発

We developed dry-type transportable storage cask (MSF69B cask) with high quality shock-absorber and seal structure. This high quality cask was proved through both 9m horizontal drop test of 1/4 scale model (2.07ton) and 9m horizontal /vertical/corner drop test of 1/2.35 scale model (10.1ton). This shock absorber is composed of balsa-wood and red-wood with high energy absorbing ability. Dependent lids structure (1^<st> lid and 2^<nd> lid contact each other and support inertia force of inner structures at 9m vertical drop test) is adopted in order to decrease lids/flange relative displacement. At 9m drop test of 1/2.35 scale model, lids/flange relative displacement is almost zero. Then, He leak rate at metal gasket dose not change before and after 9m drop test. Lids/flange relative displacement by LS-DYNA code is good agreement with that of experiment at 9m drop test of 1/2.35 scale model.

Impact Testing and Simulation of a Crashworthy Composite Fuselage Concept

A composite fuselage concept for light aircraft and rotorcraft has been developed to provide improved crash protection. The fuselage consists of a relatively rigid upper section, or passenger cabin, including a stiff structural floor and a frangible lower section which encloses the crash energy management structure. A 60-in diameter full-scale fuselage section was manufactured using a composite sandwich construction. Vertical drop tests were conducted at both 0°- and 15°-roll impact attitudes to evaluate the crashworthy features of the fuselage design. The experimental data are correlated with predictions from a finite element model developed using the non-linear, explicit transient dynamic code, MSC.Dytran.

9H 有限要素下腿モデルの試作(シンポジウム : ヒューマン・ダイナミクス2001)

The purpose of this study was development a lower leg model by the finite element method for the analysis of physical exercise and sports. In the vertical drop test simulation, the contact time of the foot model and the floor model was about 23 ms, and the vertical peak force was about 8400 N for the model weight of 60 kg. It seems that a good approximation is acquired when comparing the actual ones with that values in the experiment The vertical peak force for this boundary condition was much higher than that reported for real human running. It was observed that the highly stressed regions were the tibia, the calcaneus, the metatarsals, and the navicular in dynamic transient analysis.

Test Facilities for Radioactive Materials Transport Packages (Chicago Bridge &amp; Iron, USA)

Chicago Bridge & Iron, Research and Development Center located in Plainfield, Illinois offers the total capabilities required to perform design verification testing of hazardous waste shipping containers. The tests, defined in the US Code of Federal Regulations, Title 10, Part 71 (10CFR71), include vertical drop tests, puncture tests, crush tests, immersion tests, thermal tests, and container leak rate tests. Container structural design analysis, container manufacturing analysis, materials development testing plus dimensional analysis of individual components is also available. The test facilities meet or exceed the requirements given in the International Atomic Energy Agency (IAEA) Safety Guide, Safety Series No. 37, 1987. Additional capabilities for the design and fabrication of scale models and components for the test programme are also presented.

Preliminary characterization of parachute wake recontact

A series of tests was conducted on a 10-ft.-diameter ringslot parachute with a geometric porosity of 20% to establish the conditions under which ''wake recontact'' occurs. The vertical helicopter drop tests covered a range of mass ratios from 0.5 to 3.0 and a range of Froude numbers from 70 to 400. Data consisted of velocity time histories obtained using a laser tracker and diameter time histories obtained from photometric data. A collapse parameter based on the ratio of the maximum parachute diameter to the subsequent minimum diameter was correlated with the mass ratio M/sub R/ and the Froude number Fr or equivalently with the initial to final velocity ratio V/sub o//V/sub t/. For large values of V/sub o//V/sub t/ the collapse parameter R/sub c/ appears to be a function of M/sub R/ alone. Non-dimensional opening time and ''collapse time'' data were also correlated with M/sub R/ and V/sub o//V/sub t/. 11 refs., 10 figs., 1 tab.

Structural analysis of the controlled impact demonstration of a jet transport airplane

An analytical method has been developed for assessing crash dynamics of large transport aircraft, such as in the NASA Controlled Impact Demonstration (CID) jet crash test on December 1, 1984. The DYCAST nonlinear finite-element computer code was used in a series of progressively more difficult tasks to model complete transport aircraft crashes. Single aircraft frames and fuselage section vertical drop tests were modeled and analyzed to obtain comparisons with experimental data and to develop hybrid element crash springs for use in the large CID model. Predictions of crash and acceleration levels from a symmetric CID model agreed well with data from the CID experiment.

Designing for Aircraft Structural Crashworthiness

This report describes structural aviation crash dynamics research activities being conducted on general aviation aircraft and transport aircraft. The report includes experimental and analytical correlations of load-limiting subfloor and seat configurations tested dynamically in vertical drop tests and in a horizontal sled deceleration facility. Computer predictions using a finite-element nonlinear computer program, DYCAST, of the acceleration time-histories of these innovative seat and subfloor structures are presented. Proposed application of these computer techniques, and the nonlinear lumped mass computer program KRASH, to transport aircraft crash dynamics is discussed. A proposed FAA full-scale crash test of a fully instrumented radio controlled transport airplane is also described.