Research On The Suction Nozzle Lightweight Of Road Sweeping Vehicle Based On Multi-objective Optimization Approach

Before a great breakthrough happens in the new materials and manufacture technology,automotive lightweight in aspect of structure may be the most mature and efficient strategy in developing the energy-saving and emission reducing policy.Compared with the traditional serial analysis method,structural strength was mainly considered as performance constraints in the design process.It is difficult to meet the requirements of multi-performance design system.Taking the cleaning vehicle suction nozzle device as the research object and based on mathematical modeling and optimization theory,a lightweight method coupled with internal flow field,stiffness and dynamic performance of the suction nozzle was proposed.The main research contents are as follows:The first part,simulation and analysis on flow fields and structural performance of suction.Analyzed on the existing shortage of suction nozzle,the suction nozzle flow simulation and structural performance simulation model were established using the finite element analysis tool Fluent and Hyperworks respectively.In the flow field simulation,a three channel circular nozzle structure was firstly proposed,and the result shows that it’s better than double circular channel and two channel suction nozzle in the inlet velocity uniformity and pressure drop between the inlet and outlet of suction nozzle;Furtherly,three-phase flow（gas,solid and liquid）simulation model of three circular channel nozzle was establishment,and the rationality of three circular channel suction nozzle structure was verified.In the structural analysis,three aspects including the suction nozzle static strength,the static stiffness and modal analysis were considered.The displacement contour and stress contour of the suction nozzle in five kinds of loadsteps were obtained and the fore eight modal frequencies and vibration modes were extracted,which exhibited the disadvantage of suction nozzle structure.The second part,the relationship between suction nozzle parameters and multi-objectives was discovered.Firstly,a L₆₄（4⁹）orthogonal experiment scheme was designed;Secondly,the interaction and rules between the suction nozzle nine design variables and seven target variables was explored and summarized using principal effect analysis and Pareto analysis.The results show that the relationships between design parameters and targets were complicate.Multi-objective optimization algorithm maybe the valuable method in balancing the contradiction.The third part,the research on the lightweight methods based on multi-objective modeling and optimization algorithms.Firstly,two third order response surface models（Y₁ and Y₂）and five second order approximate response surface models（Y₃-Y₇）were built,and the fitting and forecast accuracy of seven models are up to 95%.Secondly,an intergated multi-island and archive micro genetic algorithm（MI-AMGA）was put forward,and a nozzle multi-objective optimization model was built.After achieving non optimal feasible solution set（Pareto font）,the suction nozzle optimal design parameters were obtained using the weighted ideal point utility function method.Results show that the total quality of suction nozzle was decreased from56.31kg to 41.182kg,for 26.87%,while the suction nozzle flow characteristics was balanced and the structure characteristics was improved.In total,the suction nozzle system can be simulated quickly,accurately and effectively,using the proposed multi-objective modeling and optimization technology.And the same time,the performance of multi-physical fields can be balanced in the process of lightweight design,the product lightweight can be achieved finally.