Olabi, A. G.
Olabi, A. G.
Olabi, A. G.
Now showing 1 - 4 of 4
- PublicationCrush analysis and multi-objective optimization design for circular tube under quasi-static lateral loadingThis paper addresses the energy absorption behaviour and crash worthiness optimisation of short length circular tubes under quasi-static lateral loading. Finite element (FE) models were developed using implicit FE code ANSYS to simulate the deformation behaviour and energy absorption of circular tube under lateral loading. These FE models were validated using experimental techniques to ensure that they can predict the responses of circular tube with sufficient accuracy. Response surface methodology (RSM) for design of experiments (DOE) was used in conjunction with finite element modelling to evaluate systematically the effects of geometrical parameters on the energy absorption responses of laterally crushed circular tubes. Statistical software package, design-expert, was used to apply the response surface methodology (RSM). The energy absorbing responses (specific energy absorbing capacity (SEA) and collapse load (F)) were modelled as functions of geometrical factors (tube diameter, tube thickness, and tube width). These developed functions allow predictions of the energy absorption response of laterally crushed tubes, based on their geometry parameters. Based on DOE results, parametric studies were conducted to generate design information on using the laterally crushed tubes in energy absorbing systems. Finally, the approach of multi-objective optimization design (MOD) was employed to find the optimal configuration of the proposed energy absorption structures. Design-expert software, which employs the desirability approach as optimization algorithm, was used for solving the MOD problem.
521Scopus© Citations 157
- PublicationOptimised design of nested oblong tube energy absorbers under lateral impact loadingDynamic lateral crushing of mild steel (DIN 2393) nested tube systems was conducted using a ZWICK ROELL impact tester. The tests were performed with impact velocities ranging between 3 and 5 m/s, achieved using a fixed mass impinging onto the specimens under the influence of gravity. The various nested tube systems consisted of one standard and one optimised design. Their crushing behaviour and energy absorption capabilities were obtained and analysed. In addition to the experimental work, numerical simulations using the explicit code LS-DYNA were conducted; boundary conditions matching those observed in experiments were applied to the models. Results from the numerical method were compared against those obtained from experiments. An over-prediction in force–deflection responses was obtained from the numerical code. An attempt was made to explain this inconsistency on the basis of the formation of plastic hinges and the validity of strain rate parameters used in the Cowper Symonds relation. It was found that the optimised energy absorbers exhibited a more desirable force–deflection response than their standard counterparts due to a simple design modification which was incorporated in the optimised design.
496Scopus© Citations 75
- PublicationAnalysis and optimization of sandwich tubes energy absorbers under lateral loadingIn this paper, the sandwich tubes, which consist of thin-walled circular tubes with aluminium foam core, were proposed as energy absorption devices. The sandwich tubes were laterally crushed under quasi-static loading conditions. Detailed finite element model, validated against existing experimental results, was developed using the explicit code (ANSYS-LSDYNA) to assess the energy absorption responses and deformation modes. Response surface methodology (RSM) was employed in parallel with the finite element models to perform both parametric studies and multi-objective optimization in order to establish the optimal configuration of the sandwich tube. Sampling designs of the sandwich tubes were constructed based on a D - optimal design of experiment (DOE) method. Factorial analysis was performed using the DOE results to investigate the influences of the geometric parameters on the responses of sandwich tubes. In addition, multi-objective optimization design (MOD) of the sandwich tubes is carried out by adopting a desirability approach. It was found that the tube with a minimum diameter of the inner layer and a maximum foam thickness are more suitable for use as energy absorbing components.
287Scopus© Citations 94
- PublicationOptimised design of nested circular tube energy absorbers under lateral impact loadingArrangements of mild steel (DIN 2393) nested tubes were laterally crushed by dynamic loading. The tests were performed with impact velocities ranging between 3 and 5 m/s, using a fixed mass impinging onto the specimens under the influence of gravity. Two arrangements of nested tube systems were considered; one standard and one optimised design. Their crushing behaviour and energy absorption capabilities were analysed experimentally and simulated numerically using the explicit code LS-DYNA. Results from the numerical analyses were compared against those obtained from experiments. An over-prediction in force-deflection responses was obtained from the numerical code. An attempt was made to explain this inconsistency on the basis of the validity of strain rate parameters used in the Cowper Symonds relation. It was shown that the optimised energy absorber exhibited a more desirable force-deflection response than the standard arrangement due to a simple design modification which involved mild steel cylindrical dampers.
1041Scopus© Citations 88