• International Journal of Automotive Technology
• /
• v.5 no.1
• /
• pp.47-53
• /
• 2004

In this paper, a modified and representative unit cell model was employed to study the crush behaviour of a closed cell metallic foam. The unit cell which captures the main geometrical features of the metallic foam considered was used to simulate crush behaviour in metallic foams. Both analytical using limit analysis and numerical using the finite element method were used to study the collapse behaviour of the cell. The analytical crushing stress of the foam was compared with FE results and was found to be in good agreement.

• Journal of Aerospace System Engineering
• /
• v.4 no.3
• /
• pp.1-5
• /
• 2010

Understanding the crushing behaviour of aluminum honeycombs under dynamic loading is useful for crash simulations of vehicles and for design of impacting energy absorbers. In the study of honeycomb crushing under quasi-static, dynamic loading, the most important parameter is crush strength. Crush strength is indicated to energy absorption characteristic of aluminum honeycomb. In this study, Using Finite Element Analysis carried out crush strength of hexagonal aluminum honeycomb then the results was compared with Quasi-static test. Consequently, Crush strength is different in quasi-static loading and dynamic loading about 16%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.5
• /
• pp.734-741
• /
• 2019

Objective: The objective of the study was to determine the relationship between plasma and salivary cortisol concentrations in beef cattle that were subjected to handling prior to sampling. Methods: Twenty-one Nguni cows of three age categories; 5 to 7 yr (n = 7), 8 to 10 yr (n = 6), and 11 to 13 yr (n = 8) were handled for five consecutive weeks. In the pen, a human avoidance test was performed and cattle responses to restraint in the chute and crush were observed. In addition, rectal temperature readings were taken and, faecal samples were collected and analysed for glucocorticoid metabolites. Through the handling and restraint process, excretory and vocalisation behaviour, as a sign of stress were observed and recorded. Thereafter, six cows were randomly selected and subjected to an adrenocorticotropic hormone (ACTH) challenge. Blood and saliva samples were extracted to determine cortisol concentrations. Results: Repeated handling affected (p<0.05) faecal glucocorticoid metabolites, rectal temperatures, avoidance distance, crush scores as well as urination and defaecation behaviour. Acclimation to handling was variable based on each respective parameter. Saliva cortisol concentrations increased and decreased significantly (p<0.001). A peak value of $136.78{\pm}15.869nmol/L$ was observed 30min after administration of ACTH, from a baseline value of $8.75{\pm}15.869nmol/L$. Plasma cortisol concentrations did not differ (p>0.05) across the time of sampling. A low and insignificant correlation (r = 0.0131, p>0.05) between plasma and saliva cortisol was therefore observed. Conclusion: We conclude that if beef cows are subjected to handling prior to sampling, a weak relationship exists between plasma and salivary cortisol levels.

• Steel and Composite Structures
• /
• v.27 no.1
• /
• pp.95-108
• /
• 2018

A new composite reinforced method, namely self-compacting concrete filled circular CFRP-steel jacketing, was proposed in this paper. Experimental tests on eight RC square short columns reinforced with the new composite reinforced method and four RC square short columns reinforced with CFS jackets were conducted to investigate their eccentrically compressive behaviour. Nine reinforced columns were subjected to eccentrically compressive loading, while three reinforced columns were subjected to axial compressive loading as reference. The parameters investigated herein were the eccentricity of the compressive loading and the layer of CFRP. Subsequently, the failure mode, ultimate load, deformation and strain of these reinforced columns were discussed. Their failure modes included the excessive bending deformation, serious buckling of steel jackets, crush of concrete and fracture of CFRP. Moreover, these reinforced columns exhibited a ductile failure globally. Both the eccentricity of the compressive loading and the layer of CFRP had a significant effect on the eccentrically compressive behaviour of reinforced columns. Finally, formulae for the evaluation of the ultimate load of reinforced columns were proposed. The theoretical formulae based on the ultimate equilibrium theory provided an effective, acceptable and safe method for designers to calculate the ultimate load of reinforced columns under eccentrically compressive loading.

• Journal of the Korean Society for Railway
• /
• v.1 no.1 s.1
• /
• pp.1-9
• /
• 1998

Described in this paper is the result of a study on collision analysis of TGV-K using 1-dimensional model for crashworthy design. Crashworthy design of the front end is very important because majority of the impact energy (more than 70%) is absorbed by the crush of the front end when the train is collided with an obstacle like a tank lorry. Guideline for the crashworthy design can be described from the collision analysis of the whole train using a 1-dimensional model. Since the headstock of TGV-K is not designed in a crashworthy point of view, a conceptual design of the headstock to improve crashworthiness is suggested and evaluated using 1-dimensional collision analysis. The suggested design, which adopts an energy absorber and a crashworthy headstock, shows a good behaviour on the accident scenario of SNCF (collision at 110 km/h against a movable rigid mass of 15 ton).

• Proceedings of the KSR Conference
• /
• 1998.05a
• /
• pp.361-368
• /
• 1998

Described in this paper is the result of a study on collision analysis of TGV-K using 1-dimensional model for crashworthy design. Crashworthy design of the front end is very important because majority of the impact energy (more than 70%) is absorbed by the crush of the front end when the train is collided with an obstacle like a tank lorry. Guideline for the crashworthy design can be described from the collision analysis of the whole train using a 1-dimensional model. Since the headstock of TGV-K is not designed in a crashworthy point of view, a conceptual design of the headstock to improve crashworthiness is suggested and evaluated using 1-dimensional collision analysis. The suggested design, which adopts an energy absorber and a crashworthy headstock, shows a good behaviour on the accident scenario of SNCF (collision at 110 km/hr against a movable rigid mass of 15 ton).

• Steel and Composite Structures
• /
• v.49 no.4
• /
• pp.393-405
• /
• 2023

In this paper, the energy absorption capability of a novel cruciform composite lattice structure was evaluated through the simulation of compression tests. For this purpose, several test samples of Polylactic acid cellular reinforced with continuous glass fibers were prepared for compression testing using the additive manufacturing method of material extrusion. Using a conventional path design for material extrusion, multiple debonding is probable to be occurred at the joint regions of adjacent cells. Therefore, an innovative printing path design was proposed for the cruciform lattice structure. Afterwards, quasistatic compression tests were performed to evaluate the energy absorption behaviour of this structure. A finite element model based on local material property degradation was then developed to verify the experimental test and extend the virtual test method. Accordingly, different combinations of unit cells' dimensions using the design of the experiment were numerically proposed to obtain the optimal configuration in terms of the total absorbed energy. Having brilliant energy absorption properties, the studied cruciform lattice with its optimized unit cell dimensions can be used as an energy absorber in crashworthiness applications. Finally, a cellular structure will be suitable with optimal behavior in crush load efficiency and high energy absorption.