Model Validation and Verification of Energy absorption Characteristics of Honeycomb Core
- Paper number
IAC-07-C2.1.07
- Author
Mr. G. Sunil Kumar, Indian Space Research Organisation (ISRO), VSSC, India
- Coauthor
Dr. R. Ramesh Kumar, Indian Space Research Organisation (ISRO), VSSC, India
- Year
2007
- Abstract
Honeycomb core has high potential for energy absorption and is widely used for impact landing of struts of space vehicle, separation systems in inter stages and air dropping of equipments. Aluminum honeycomb core has high specific crush strength. The basic design variables are honeycomb core height, core density for a given impact mass and impact velocity. When a mass moving with certain velocity, impacts on the core, the energy absorbed per unit mass of core consumed or crushed and is expressed in kJ/kg. To evaluate this, the permanent deformation of the honeycomb core under impact has to be obtained either by test or by analysis. The most critical issue in the evaluation of energy absorption capacity of the honeycomb core is the bouncing of mass on impact during testing and numerical instability in the analysis. If the impact mass is small there will not be any permanent deformation and the elastic deformation causes the bouncing. On the other hand, if the mass is very high during impact the core is bottomed out (fully crushed) then also the mass bounces. As on today no mathematical model validation of honeycomb core and its validation through a standard drop test are reported in the literature. In the present study, to eliminate bouncing of impact mass, to ensure a free fall of mass normal to the core surface and to provide average value about seventy numbers of honeycomb core with different densities and core height are subjected to drop test and then explicit dynamic analysis is followed to capture the permanent deformation due to the impact. A comparison of energy absorption capacity of the core obtained between the test and analysis is made. Experiment is conducted by carrying out drop test for simulating free fall impact normal to the bare aluminum honeycomb core with different core height with 15 mm, 20 mm and 30 mm with different densities. The permanent deformation of the honeycomb core due to a 5kg mass sitting over the core from a height of 15 m is measured and statistical data is generated on energy absorption capacity. Typically, for Al core height of 20 mm the energy absorption obtained from the test is 28 kJ/ kg as against the analysis result of 26.21kJ/ kg. The mathematical model has been validated and verified through test.- Abstract document
- Manuscript document
IAC-07-C2.1.07.pdf (🔒 authorized access only).
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