Curvilinear Variable Stiffness 3D Printing For Improved Mechanical Performance

<div>Continuous Curvilinear Variable Stiffness (CCVS) is proposed as a novel design technique to generate Variable Stiffness design for improving the performance of composite panels featuring open-hole cut-outs. Compared to existing VS design techniques, CCVS steers the fibers around the cut-out without breaking at the holes using only a single design variable the geometry. The technique utilises a numerical method known as Source Panel method, which is typically utilised in the fluid dynamics world. Utilising this technique, the performance of an open hole ASTM D5766 coupon manufactured using Fused Filament Fabrication (FFF) was improved 16-38% depending on the ratio of the hole to the width of the specimen. The technique was further</div><div>improved on to allow for arbitrary geometries such as fuselage cut-outs. A fuselage cut-out case was examined, and it was shown that a CCVS design can improve the performance over a QuasiIsotropic design by 57%. To validate CCVS, it is necessary to first manufacture and validate the part. This was done by developing a robotic 3D printing work-cell capable of 5 axis of material deposition of both thermoplastic and pre-impregnated carbon fiber. Finally, an in-process inspection technique was developed using a laser line scanner in the work-cell for the purposes of quality control. </div>

Curvilinear Variable Stiffness 3D Printing For Improved Mechanical Performance

<div>Continuous Curvilinear Variable Stiffness (CCVS) is proposed as a novel design technique to generate Variable Stiffness design for improving the performance of composite panels featuring open-hole cut-outs. Compared to existing VS design techniques, CCVS steers the fibers around the cut-out without breaking at the holes using only a single design variable the geometry. The technique utilises a numerical method known as Source Panel method, which is typically utilised in the fluid dynamics world. Utilising this technique, the performance of an open hole ASTM D5766 coupon manufactured using Fused Filament Fabrication (FFF) was improved 16-38% depending on the ratio of the hole to the width of the specimen. The technique was further</div><div>improved on to allow for arbitrary geometries such as fuselage cut-outs. A fuselage cut-out case was examined, and it was shown that a CCVS design can improve the performance over a QuasiIsotropic design by 57%. To validate CCVS, it is necessary to first manufacture and validate the part. This was done by developing a robotic 3D printing work-cell capable of 5 axis of material deposition of both thermoplastic and pre-impregnated carbon fiber. Finally, an in-process inspection technique was developed using a laser line scanner in the work-cell for the purposes of quality control. </div>

Variable Stiffness Design and Analysis of Flexure Hinge Based on ID-LEJ

In recent years, compliant mechanisms have attracted more and more attention of scholars at home and abroad, and achieved rapid development. The introduction of flexible variable stiffness design in flexible mechanism can not only improve the safety of human-computer interaction, but also improve the adaptability of the machine. Because the ID-LEJ (Inside-Deployed Lamina Emergent Joint) is a kind of LEMs and has very good bending performance. In this paper, the rotary ID-LEJ flexure hinge is proposed based on ID-LEJ hinge, to maximize the bending capacity of the hinge. In order to realize variable stiffness of rotary ID-LEJ, four sliders are arranged in the rotary ID-LEJ to change the stiffness of the hinge. The variable stiffness of the hinge is analyzed by Equivalent system and Finite element analysis. When the slider is symmetrically divided (yl1=yl2=yr1=yr2) the bending equivalent constant of the variable stiffness hinge varies continuously from 30.8 n · mm / rad ∼ 38.2n · mm / rad. And when the slider is asymmetrically distributed (yl1=yl2≠yr1=yr2) The bending equivalent constant of the variable stiffness hinge varies continuously from 30.8n · mm / rad to 34.2 · mm / rad. The results show that the variable stiffness performance is very flexible and stable.

An ultra-broad-range pressure sensor based on gradient stiffness design

The question of how to make artificial intelligence robots perceive the power of "light as a feather" and "heavy as a mountain" at the same time has always been a...

The impact and sensitivity analysis of beam and stringer for stiffness center of composite wing structure

Wing stiffness center should be determined firstly for structure detail design. The present study focused on the impact analysis of beam and stringer for wing cross-section stiffness center based on thin wall structure mechanics theory. In order to discuss the impact of beam and stringer on stiffness center, the sensitivity formulas for stiffness center of wing cross-section were derived and expressed in terms of the dimension and layout of beams and stringers. The results indicated that the structural layouts of beam and stringer were important influencing factors in stiffness detail design of full composite wing structure. The research results can provide an important reference for the stiffness design and aeroelastic design of the full composite wing.

Bi-objective optimization design of material stiffness for improving contact interface performances

The characteristics of contact interfaces such as the distribution uniformity of the contact pressure and the effective contact area play a crucial role in engineering equipment. To investigate the influences of the variable material stiffness optimization (VMSO) design on the contact characteristics of the contact interfaces in an assembly, an heuristic-based VMSO algorithm is developed in this paper. A bi-objective function is defined by including both the distribution uniformity of the contact pressure and the effective contact area. A single bolted joint model is adopted as a design example. The results indicate that optimizing the stiffness of the materials around the contact interface is an effective approach to enhance the distribution uniformity of the contact pressure, increase the effective contact area and decrease the maximum contact pressure. Furthermore, the improvement effectiveness provided by the proposed variable stiffness design is better than that provided by the traditional variable thickness design.