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>

Digital Twin of an Optical Measurement System

Digital twins of measurement systems are used to estimate their measurement uncertainty. In the past, virtual coordinate measuring machines have been extensively researched. Research on digital twins of optical systems is still lacking due to the high number of error contributors. A method to describe a digital twin of an optical measurement system is presented in this article. The discussed optical system is a laser line scanner mounted on a coordinate measuring machine. Each component of the measurement system is mathematically described. The coordinate measuring machine focuses on the hardware errors and the laser line scanner determines the measurement error based on the scan depth, in‑plane angle and out‑of‑plane angle. The digital twin assumes stable measurement conditions and uniform surface characteristics. Based on the Monte Carlo principle, virtual measurements can be used to determine the measurement uncertainty. This is demonstrated by validating the digital twin on a set of calibrated ring gauges. Two validation tests are performed: the first verifies the virtual uncertainty estimation by comparison with experimental data. The second validates the measured diameter of different ring gauges by comparing the estimated confidence interval with the calibrated diameter.

Volatile Liquid Detection by Terahertz Technologies

The prospect of being able to move through security without the inconvenience of separating liquids from bags is an exciting one for passengers, and there are important operational benefits for airports as well. Here, two terahertz (THz) systems, 100 GHz sub-THz line scanner and attenuation total reflection-based THz time domain spectroscopy (TDS), have been used to demonstrate the capability of identifying different liquid samples. Liquid samples’ THz complex permittivities are measured and their differences have contributed to the variation of 100 GHz 2D images of volatile liquids with different volumes inside of cannister bottles. The acquired attenuation images at 100 GHz can easily be used to distinguish highly absorbed liquids (Water, Ethanol, Fuel Treatment Chemicals) and low loss liquids (Petrol, Diesel, Kerosene and Universal Bottle Cleaner). The results give a promising feasibility for mm-wave imager and THz spectroscopy to efficiently identify different volatile liquids.