Extraction and evolution of grader’s bionic morphological feature line using shape structure behavior function model

To improve the innovation of agricultural machinery product styling,this paper proposes a shape structure behavior function(SSBF)model suitable for the industrial design field.The feature line evolution method combining shape grammar and genetic algorithm was used for modelling the of the grader,which not only maintains the product style characteristics but also reflects the typical identification characteristics of the bionic prototype and produces a new product modelling scheme.By conducting cognitive and recognition experiments on product styling features,the ranking of product styling features and the contribution of each component to product styling were determined.The method of combining shape grammar and quadratic Bézier curve was used to express and encode feature lines,and genetic algorithm was used to evolve biomimetic forms to form product feature lines with typical biological morphological features;The extracted form bionic elements were integrated into the grader modelling design,and the interaction evaluation was carried out through the genetic algorithm evolution scheme.The basic form elements were extracted and analyzed,and the deduction rules were formulated and reorganized.The derived feature line geometric data considered the product’s image features and the bio-inspired prototype,which can be used for the follow-up guidance of industrial design schemes.

Effect of head swing motion on hydrodynamic performance of fishlike robot propulsion

This paper studies the effect of the head swing motion on the fishlike robot swimming performance numerically. Two critical parameters are employed in describing the kinematics of the head swing： the leading edge amplitude of the head and the trailing edge amplitude of the head. Three-dimensional Navier-Stokes equations are used to compute the viscous flow over the robot. The user-defined functions and the dynamic mesh technology are used to simulate the fishlike swimming with the head swing motion The results reveal that it is of great benefit for the fish to improve the thrust and also the propulsive efficiency by increasing the two amplitudes properly. Superior hydrodynamic performance can be achieved at the leading edge amplitudes of 0.05L （ L is the fish length） and the trailing edge amplitudes of 0.08L. The unsteady flow fields clearly indicate the evolution process of the flow structures along the swimming fish. Thrust-indicative flow structures with two pairs of pressure cores in a uniform mode are generated in the superior performance case with an appropriate head swing, rather than with one pair of pressure cores in the case of no head swing. The findings suggest that the swimming biological device design may improve its hydrodynamic performance through the head swing motion.

Wear Behavior of a Bio-inspired Bearing for off-center Loads

Misalignment is one of the most common causes of wear in bush bearings.Design improvements have been proposed by many researchers.Unfortunately,it did not efficiently reduce the misalignment.Classic geometrical designs sometimes reach their limits.For this reason,a bio-inspired design is proposed to solve the impediment.In this article,a bio-inspired bearing suited to misalignment was tested and compared to a classical bush bearing.The contact pressures of both bearings were compared with static Finite Element(FE)simulations for off-center load.Due to the complex shape of the involved contact,the performances of both bearings were also studied over time.Their wear behaviors were predicted with a numerical method.The methodologies emplaced to simulate the wear were described in this paper.Particularly,the wear coefficient determination obtained by experimental testing was detailed.The pressure value,the contact zone and the wear depth were compared and discussed.The wear results for the classical bearing are in accordance with the literature.The simulations show a deeper wear on the classical bush bearing than on the bio-inspired bearing.This leads to a longer period of service life for the bio-inspired bearing.