JIANGSU UNIVERSITY

A method for shape-performance control by ultrasonic rolling combined with selective laser melting is provided, which includes following steps: S1, establishing a three-dimensional model of a component to be processed, and setting printing process parameters; S2, after nitrogen gas is filled into a forming cavity to reduce an oxygen content to a preset value, lowering a forming substrate and raising a powder substrate, laying powder from the powder substrate onto the forming substrate by a scraper, recovering excess powder, and after the laying is completed, melting the powder by a laser galvanometer to form a solid layer, and cycling for several times; S3, performing ultrasonic rolling on a surface of the solid layer; S4, cycling steps S2 and S3 until the component is formed, and ending the cycling; and S5, performing ultrasonic rolling on a surface of a formed component to obtain a solid component.

A shape follow-up support device for selective laser melting and a method thereof are provided. The device includes a lifting base, where the lifting base is provided with an inner cavity, and a top wall of the lifting base is provided with multiple first through holes communicated with the inner cavity of the lifting base, and the multiple first through holes are arranged at equal intervals. Multiple driving assemblies are arranged in the lifting base; output ends of the driving assemblies extend out of the lifting base through the first through holes and are provided with support rods, and protruding ends of the support rods are detachably connected with sacrificial assemblies. A porous substrate is provided with multiple second through holes, and the multiple second through holes are in one-to-one correspondence with the multiple first through holes and communicate with the multiple first through holes.

A method for shape-performance control by ultrasonic rolling combined with selective laser melting is provided, which includes following steps: S1, establishing a three-dimensional model of a component to be processed, and setting printing process parameters; S2, after nitrogen gas is filled into a forming cavity to reduce an oxygen content to a preset value, lowering a forming substrate and raising a powder substrate, laying powder from the powder substrate onto the forming substrate by a scraper, recovering excess powder, and after the laying is completed, melting the powder by a laser galvanometer to form a solid layer, and cycling for several times; S3, performing ultrasonic rolling on a surface of the solid layer; S4, cycling steps S2 and S3 until the component is formed, and ending the cycling; and S5, performing ultrasonic rolling on a surface of a formed component to obtain a solid component.

A method of strengthening through real-time coupling of electrical pulses and laser shock waves is provided. The initial time and duration of the electrical pulses are controlled to be matched with the initial time and duration of the laser shock waves, so that the electrical pulses and the laser shock waves are coupled in real time for material strengthening, the plasticity and the strength of the material are greatly improved, and a large area of the workpiece is uniformly strengthened. By simultaneously introducing the electrical pulses into the pulse current-assisted LSP, a great strengthening effect is achieved through the combination of the electrical pulses and the pulse current-assisted LSP in a short time, thereby reducing the internal defects of the material to a certain extent and further increasing the fatigue life of the material.

A modeling method for electromagnetic forces and vibration response of a SPM machine, belonging to the field of combined electromagnetic field and structural mechanics computation. First, build the circuit-based EMN model, regular EMN model, and discrete EMN model with equivalent magnetic source and permeance for the different regions of the SPM machine. Second, based on the spatial relationships between each part in the SPM machine, the EMN models of each region are interconnected to form a complete model of the discrete EMN model. The non-sinusoidal high-frequency current harmonics are introduced as input excitation to the discrete EMN model. The global nonlinear matrix equation is solved simultaneously to determine the magnetic flux density in the air gap permeance elements, enabling the air gap electromagnetic force density calculation. Subsequently, the calculated electromagnetic force density is transformed into concentrated forces on the surface of the stator teeth.

The present disclosure provides a laser peen forming device and method with an adjustable absorbing layer. The laser peen forming device with the adjustable absorbing layer includes a laser peening system, an x-y-z three-axis machining platform, and a working tank, where the working tank is secured on the x-y-z three-axis machining platform; the laser peening system is located above the working tank; a laser irradiation system and a three-dimensional information acquirer are further arranged above the working tank; a workpiece, a tool anode, a heating device, and a temperature sensor are arranged in the working tank; the workpiece is connected to a cathode of an electric box; the tool anode is connected to an anode of the electric box; the tool anode is located above the workpiece and keeps a predetermined distance from the workpiece; and the working tank is connected to a phosphating solution flowing system.

A method of strengthening through real-time coupling of electrical pulses and laser shock waves is provided. The initial time and duration of the electrical pulses are controlled to be matched with the initial time and duration of the laser shock waves, so that the electrical pulses and the laser shock waves are coupled in real time for material strengthening, the plasticity and the strength of the material are greatly improved, and a large area of the workpiece is uniformly strengthened. By simultaneously introducing the electrical pulses into the pulse current-assisted LSP, a great strengthening effect is achieved through the combination of the electrical pulses and the pulse current-assisted LSP in a short time, thereby reducing the internal defects of the material to a certain extent and further increasing the fatigue life of the material.

The present invention provides a material-based subdomain hybrid cellular automata algorithm for solving material optimization of thin-walled frame structures, including an outer loop and an inner loop: the outer loop is to define and update the target cost for the inner loop; the inner loop is to adjust material using a PID control strategy according to the nominal flow stress of a current cell and the nominal flow stress of candidate materials, so that a current cost of the inner loop converges to the target cost. During the execution of the inner loop, the cellular material update rule based on the PID control strategy is employed to update cellular material, to define the candidate material library and the nominal flow stress, to update the nominal flow stress of current cell, to compare the nominal flow stress with the actual flow stress of each material in the candidate material library, to select the candidate material closest to the nominal flow stress as the selected material grade for the current cell and to replace the material parameters of the current cell with the mechanical parameters of the selected material. The present invention can efficiently solve nonlinear the dynamic response optimization problems containing a large number of material variables, significantly improving the robustness of the algorithm.

Disclosed is a multi-model predictive control method for a Pichia pastoris fermentation process, including: dividing prior data into m training sample clusters by using a fuzzy C-means algorithm (FCM); obtaining, for each sample cluster, a corresponding prediction model by using a least squares support vector machine (LSSVM) and an improved particle swarm optimization method (IPSO); then, designing a corresponding predictive controller; and finally, calculating a deviation between an output of an object and an output of each sub-prediction model at each sampling time to establish a multi-model fusion predictive controller. According to the method, the adaptive ability of the model is improved and an actual state of a nonlinear system is described more accurately.

The present disclosure relates to an eccentric extreme high-speed-rate laser hybrid manufacturing method for a rotary engineering component. By positioning an extreme high-speed-rate laser direct energy deposition machining head at a predetermined eccentric distance, the damage caused by reflected light to the machining head is effectively reduced, to prolong a service life of the machining head. Also a conventional form of a molten pool in extreme high-speed-rate laser direct energy deposition can be changed, namely from a “falling” form caused by a high-speed movement and a gravity to a “climbing” form. Thus, in extreme high-speed-rate laser direct energy deposition machining, the molten pool has a longer time to fully contact a surface of the rotary engineering component to form desirable bonding performance.