On The Investigation Of Mechanical Properties Of 3D Printing Nacre Composite Under Static And Dynamic Conditions

Nacre is a special sort of biological structure that widely exists in various living organisms that own shells,such as conch,abalone and so on in nature.Through the evolution of millions of years,it has formed a special kind of ‘brick and mortar' structure which is analogous to architectures via smart combinations.It is comprised of two parts that the dominant part is made up of calcium carbonate that is hard but brittle and the matrix part is composed of organic substance that is soft but is comparatively good in terms of ductility.Although this type of structure is mostly occupied by calcium carbonate,it possesses outstanding mechanical properties compared with pure calcium carbonate by contrast.And under the status that the sacrifice of strength and modulus is not big,it owns more excellent ductility and better energy dissipation capacities conversely.So as a result,this exceptional character of itself has won more concentrations and investigations.With the consistent developments ofcomposite investigations and the constant deepening of biomimetics domains,nacre has received much attentions and must acquire more in-depth researches and burgeons in the future.While until today,relevant investigations are relatively lack with regard to nacre composite materials.So the investigation on mechanical properties of nacre composite materials not only has fine scientific significance,but also own practical values.The main research work of this paper is the investigation of mechanical properties of nacre composite material and concentrations on quasi-static compressive mechanical properties of nacre composite material and its dynamic mechanical characters under bullet penetration and this paper is divided by two parts:The first part is the fabrication of nacre composite material specimens via3 D printing molding method.3D printing molding technology has characters like high efficiency,fast,material economization and relatively high precision and therefore has acquired more and more applications,particularly in the composite investigation domains.3D printing specimens applied in this paper were made up of rigid non-transparent plastic Vero Blue as the dominant part and soft rubber Tango Black as the matrix part.Then the fabrication of nacre composite material specimens was carried out by means of different detailed dimensions changing and the exploration of influences of detailed dimensions on compressive mechanical properties of nacre composite material specimens was in progress under quasi-static engineering conditions by means ofquasi-static loading application method.Meanwhile,with the combination of numerical simulation results using finite element analysis software ABAQUS,a portion of experiments were chosen for relevant validations and references and correlative validations and references demonstrated that results coincide relatively good.We can find out by quasi-static compressive results that some mechanical properties of nacre composite material for example stress-strain curves,compressive modulus,compressive strengths and crack absorption energies were influenced in a relatively large extent by detailed dimensions of material such as aspect ratios of hard blocks,widths of hard blocks or thicknesses of soft glue layers.At the same time,conclusions displayed us that a relatively small thickness of soft glue layers and a relatively large aspect ratio of hard blocks have obvious influences on mechanical properties.The second part is the establishment of dynamic analysis numerical models of 3D printing nacre composite material with different detailed dimensions and from single layer to multiple layers mainly by means of finite element ABAQUS.Due to the reason that the materials adopted were rigid plastic Veromagenta and Tangoblackplus that were pointed out by reference documents,which were very similar to materials of specimens applied in quasi-static experiments,the material properties of dynamic analysis and quasi-static experiments were very similar.We investigated regular pattern developments of dynamic mechanical properties of 3D printing nacre composite material under the bullet penetration conditions by the establishment of 3D printing nacre composite material modelswith bullets.We could find out that penetration resistance properties of nacre composite material have intimate relationships with aspect ratios of hard blocks,thicknesses of soft glue layers and layer installations of composite material.And comparisons of simulation and experiment of reference document were relatively ideal.Generally speaking,this paper investigated regular pattern developments of mechanical properties of 3D printing nacre composite material under the static and dynamic conditions and under situations with the changing of some parameters through experiments and finite element ABAQUS method.This has definite reference values and importance for correlative scientific investigations as well as practical engineering applications.