Neural Network Processing of Audible Sound Signal Parameters for Sensor Monitoring of Tool Conditions

The increase of productivity in manufacturing processes largely relies on the successful introduction of flexible automation in machining processes. Such success, in turn, is largely based on the availability of data on the operating conditions, provided by reliable sensing devices. In the present work, experimental verifications of the possibilities of utilizing audible sound based sensing methods for in-process identification of tool conditions are presented for band sawing processes carried out on aluminium alloy and low carbon steel plates

Metrological Analysis of High Performance Composite Laminates through Advanced Ultrasonic Nondestructive Inspection

In this work, the study of the influence of impact conditions on damage generation in high performance composite materials is carried out through the application of an advanced ultrasonic (UT) non-destructive inspection (NDI) technique known as UT full waveform scanning. This technique is based on the pulse-echo immersion testing method and allows for the quantitative analysis of the internal material structure in the entire composite laminate volume (2 1/2 D evaluation). The composite material under examination consists of 20 µm diameter carbon fibre reinforced plastic (CFRP) laminates fabricated by superimposing 150 µm unidirectional (+45° or -45°) tape layers and 210 µm bi-directional (0°, 90°) fabric layers. A 15 MHz focused UT probe was used to scan CFRP composite laminate samples subjected to impact testing conditions. The scope of the UT NDI metrological analysis is the quality assurance of the CFRP composite laminates (actual laminate thickness evaluation, correct stacking sequence verification) and the characterisation and measurement of impact damage development in the entire composite material volume (in-plane delamination damage extension, damage position in the thickness direction, and damage transition in the laminate stacking sequence

Ultrasonic Non-Destructive Evaluation of AlSiC Metal Matrix Composite Experimental Heat Pipe Module

An advanced ultrasonic non-destructive evaluation technique based on the detection and analysis of full ultrasonic waveforms was applied to an experimental heat pipe module made of an innovative AlSiC metal matrix composite. The prototype heat pipe module was subjected to 80 hours of thermal fatigue tests between -40 °C and +125 °C with 45 min permanence at each temeprature, The scope of the work is the identification of possible delamination damage at the joints between the different material tubes and the AlSiC MMM base plate

Critical Aspects in the Application of Acoustic Emission Sensing Techniques for Robust and Reliable Tool Condition Monitoring

Acoustic emission sensing techniques for tool condition monitoring (TCM) in machining processes have been widely studied in recent years. Some approaches have been developed and successfully implemented in industry. However, standard solutions allowing for a quick and easy application of this sensor monitoring method have not been found yet. This is basically due to the great complexity associated with tool wear mechanisms together with critical aspects in the design of cutting tests for tool wear monitoring experimentation and in the set-up of the measurement chain. In this work, the main critical points associated with the definition of the cutting tests for TCM have been analysed. The study has revealed that it is necessary to pay special attention to the previous wear level in the tool and to the way it was achieved. Besides, the need for a standardised methodology for cutting test design, allowing for a better comparison of results obtained through different TCM test procedures, has been evaluated. As a first approach, the minimum set of elements and characteristics that should be included in such standardised methodology has been established

Quality Evaluation of Thermoplastic Composite Material Single-Lap Joints

The joining of glass fibre reinforced polymer (GFRP) matrix composite materials by structural bonding still presents difficulties due to the adopted bonding process, the interface properties and the control of the adhesive thickness. In this paper, the first results of a study on the characterisation of single lap bonded joints made of glass fibre reinforced propylene thermoplastic matrix composite laminates are presented. Two different adhesive types commercially available for thermoplastic polymers have been utilized. The considered factors have been the joint static strength and the joint quality evaluated through advanced ultrasonic nondestructive evaluation

Advanced Utrasonic System for High Performance Composite Laminate Nondestructive Evaluation

A quantitative non-destructive evaluation (NDE) of impact damaged biaxial and quadriaxial non-crimp fabric (NCF) composite laminates made by resin infusion under flexible tooling (RIFT) technology using a volumetric ultrasonic (UT) pulse-echo immersion testing system was carried out. NCF composites laminates made by RIFT technology were subjected to drop weight low-velocity dynamic tests to generate impact damage in the composite material. The main scope of the UT NDE analysis is the characterisation, measurement and comparison of the damage development in the entire laminate material volume