Parameter Optimization And Experimental Study Of Vibration Compaction Forming Machine

In order to standardize the compaction process of the semi-rigid base test piece in the laboratory,and to make it possible to simulate the actual rolling conditions of outdoor vibratory roller operation,this paper designs a new vibratory compaction forming machine.Currently,there are multiple types of vibration forming machines in the market,and their reference standards are different as well.Most vibration compaction forming machines do not adopt an upper-lower structure,and the theoretical model thereof is a one-degree-of-freedom mechanical model,while the vibratory rollers on site usually adopt the two-degree-of-freedom mechanical model.Besides,the machines also have defects in their structures.Alongside that,there are a few vibration compaction molding machines adopt the upper-lower structure and the two-degree-of-freedom mechanical model,but an external motor is used in the vibration device to drive the eccentric block to rotate to generate an exciting force through a mechanical transmission method such as a universal joint,thereby causing the problems such as insecure mechanical transmission and a large machine footprint.In view of the above problems,this paper designs and produces a new vibratory compaction molding machine.The two-degree of freedom model is adopted in the machine,enabling the machine has the same mechanical model with the vibratory roller.In addition,the writer combines the power source and the excitation source,and builds two vibration motors in the lower part,and use the self-balancing principle produced by the two vibration motors to offset the horizontal forces mutually and only vertical forces are generated to vibrate and perform compaction.Based on this design idea,the writer first used 3D software to paint the mechanical structure,and converted into a 2D drawing for production and processing.Given that there will be inconsistency between practical operation and theoretical design,the writer also measures and debugs the vibration parameters of the prototype,such as amplitude,frequency,excitation force and static pressure,to ensure the vibration parameters of the prototype meet the standard and can operate normally.The final debugging results are as follows: When the frequencies of the first vibration motor and the second vibration motor are 61.98 Hz and 63.00 Hz,respectively,the vibration frequency of the vibration compaction molding machine is within 30 ± 1Hz,the average amplitude of the upper part is 417μm,the lower The average amplitude is 1262.5 μm,and the vibration isolation rate is 67%.The above data fully verify the high vibration damping performance of the double-clamp rubber vibration damping device.By testing this prototype,the writer draws the following data: The optimal vibration compaction period of this prototype is up to 100 s.In terms of unconfined compressive strength,the test piece of vibration compaction of the prototype reaches 185.07 k N,and the static compaction thereof is only 115.215 k N,realizing an increase of 69.855 k N,60.6%.During the test,since most of the test pieces are molded using an integrated test die,after the molding is completed,the demolding machine is used to force the test piece to be pushed out,which will damage the formed test piece.Therefore,the writer conducted a comparative test using a split test die and an integrated test die,and found that the demolding method has less impact on the strength of the formed test piece,and the strength is inversely proportional to the height and the diameter of the formed test piece.Therefore,when the split test die is used,the test die bolts need to be highly tightened to avoid that the diameter of the test piece does not meet the standard and the strength is not enough.