Multiobjective crashworthiness optimization of ultrahigh performancefiberreinforced concrete beams with steel bars under impact loading(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2019年02期
- Page:
- 82-90
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Multiobjective crashworthiness optimization of ultrahigh performancefiberreinforced concrete beams with steel bars under impact loading
- Author(s):
- FAN Wei1; 2; ZHANG Zhiyong1; SUN Yang; ZHANG Zewen1
- (1. School of Civil Engineering, Hunan University, Changsha 410082, Hunan, China; 2. Key Laboratory forWind and Bridge Engineering of Hunan Province, Hunan University, Changsha 410082, Hunan, China)
- Keywords:
- bridge engineering; ultrahigh performance fiberreinforced concrete (UHPFRC) beam; impactresistant performance; peak crash force (PCF); ratio of energy absorption to price (REP); response surface method; multiobjective optimization
- PACS:
- -
- DOI:
- -
- Abstract:
- To solve the main contradiction between the impact resistance and cost of ultrahigh performance fiberreinforced concrete (UHPFRC) beams, a multiobjective optimization study was carried out. Firstly, a multiobjective optimization mathematical model was established, where the peak crash force and the energy absorption to price ratios were regarded as the objective functions, and the crosssection aspect ratio of a UHPFRC beam, the UHPFRC strength, the longitudinal reinforcement ratio, and the volumetric ratio of the stirrup were set as the design variables. Secondly, based on the design of the response surface experiments, the sample points were selected, and a highorder response surface model was established through a nonlinear contact finite element (FE) analysis. Statistical analysis techniques, such as an analysis of variance, were used to verify the overall fitting effect and the prediction accuracy, and the sensitivity of the parameter changes was also studied. Finally, a response surface proxy model and multiobjective genetic algorithm were combined to form a multiobjective optimization analysis method for the impactresistant performance of UHPFRC beams. The results show that increasing the longitudinal reinforcement ratio and the aspect ratio of the crosssection appropriately in the UHPFRC beam，using a UHPFRC material with a lower strength can significantly improve the energy absorption to price ratio, and reduce instantaneous impact force.Among these factors, increasing the crosssection aspect ratio improves the impact resistance of the beam, but also leads to an increase in the contact force.The increase in the UHPFRC strength leads to significant increases in the contact stiffness and instantaneous impact force, but apparently cannot improve the energy absorption to price ratio. The longitudinal reinforcement ratio increase can not only improve the energy consumption of the UHPFRC beam, but also has little effect on the impact force. The change in the amount of stirrup has a limited influence on the peakcrash force and the energy absorption to price ratio. The response surface proxy model can be effectively used to predict the dynamic response of an impact. In addition, based on a reliability analysis of ultrahigh performance fiber reinforced concrete beams,when combined with the multiobjective genetic algorithm, Pareto frontier surface meeting different design requirements can be obtained, and the design parameters corresponding to each set of objective function values can be given. The above optimization methods and concepts will be better applied to the optimization design of similar problems (such as a rolling stone impact, vehicle impact, and ship collision), and will promote the effective application of UHPFRC in impact protection structures. 3 tabs, 8 figs, 25 refs.
Last Update: 2019-04-01