Controlling the sensor properties of smart structures produced by metal forming

2022

Prod. Eng. Res. Devel.

Self Cite

In recent years, the trend to extend the functionality of passive metallic structures in mechanical engineering through sensor integration has emerged. This trend is driven by the growing demand for monitoring and/or control approaches. Current state of the art sensory structures and machine elements are successfully produced by integrating sensors into metallic structures using various joining techniques. However, the widespread implementation of sensory structures and machine elements has a long way to go to be achieved. For this purpose, the sensory structures must be produced not only as standardized components, but also cost-effectively with flexible configuration of the sensory characteristics and the integration of associated electronics. This paper provides an overview of the latest joining technologies for sensory structures. A discussion of the features of each joining technique will be given. In view of the importance of force/torque measurement in load-bearing structures and machine elements, an overview will be provided on the advantages and challenges of joining processes that substitute electromechanical transducers with optical non-contact measurement techniques.

Section: Rotary Swagingmentioning

confidence: 99%

Sensor-integrated structures in mechanical engineering: challenges and opportunities for mechanical joining processes

2022

Prod. Eng. Res. Devel.

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“…For example, piezoelectric transducers have been integrated into metallic structures by die casting [38,39] or through additive manufacturing [40,41]. In this field, joining by forming has proven to be a particularly suitable and economic technology [42][43][44]. Here, transducers are pretensioned and integrated into hollow structures through force-or force-and form-fit joining by means of forming techniques, like rotary swaging (see Figure 1).…”

Section: Background Of Sensor Integrated Load-bearing Structuresmentioning

confidence: 99%

Sensor Integrated Load-Bearing Structures: Measuring Axis Extension with DIC-Based Transducers

2021

Sensors

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In this paper we present a novel, cost-effective camera-based multi-axis force/torque sensor concept for integration into metallic load-bearing structures. A two-part pattern consisting of a directly incident and mirrored light beam is projected onto the imaging sensor surface. This allows the capturing of 3D displacements, occurring due to structure deformation under load in a single image. The displacement of defined features in size and position can be accurately analyzed and determined through digital image correlation (DIC). Validation on a prototype shows good accuracy of the measurement and a unique identification of all in- and out-of-plane displacement components under multiaxial load. Measurements show a maximum deviation related to the maximum measured values between 2.5% and 4.8% for uniaxial loads ( and between 2.5% and 10.43% for combined bending, torsion and axial load. In the course of the investigations, the measurement inaccuracy was partly attributed to the joint used between the sensor parts and the structure as well as to eccentric load.

“…Müller et al developed an in-process monitoring method for the preload evaluation and for fault detection during the integration of piezo modules into micro-structured aluminum sheets [14]. In order to obtain defined preload and therefore reproducible sensory properties of the sensory structures produced by incremental forming processes, Krech et al use the signal of the force transducer that is to be integrated to control its preload during the integration process [15].…”

Section: Motivationmentioning

confidence: 99%

“…Utilizing the transducer already during the integration of the sensor into the structure to control the joining process (see [15]) raises the question: which process conditions and signal processing allow for a process integrated calibration of sensory structures? A successful process integrated calibration of sensory structures could help to increase the economic efficiency of the manufacturing chain by avoiding the downstream calibration step.…”

Section: Motivationmentioning

confidence: 99%

See 1 more Smart Citation

In-process calibration of smart structures produced by incremental forming

Krech

2020

Prod. Eng. Res. Devel.

Self Cite

Smart load-bearing structures are created by forming integration of functional materials into passive metallic components with target-oriented pre-stress conditions by rotary swaging. Their sensory capability cannot only be used during the utilization but also during the manufacturing phase. Previous works demonstrated how this capability paves the way for efficient monitoring and controlling of the used integration process. In search of an even higher overall efficiency of the manufacturing chain, the subsequent costly calibration step deserves closer attention. Therefore, a cost- and time-efficient approach for the process-integrated calibration of a sensor-integrated structure is proposed in this paper. During the in-process calibration, the acting process forces are measured both in the integrated sensor and in a special-built clamping fixture. The measured data can be transferred into calibration slopes of the sensory structures. A suitable signal processing based on the process characteristics is performed to compensate interference effects on the raw signals. As a result, an accuracy of the calibration better than 2% of the nominal value compared to an offline standardized calibration is achieved with the in-line calibration method. Consequently, efficiency in the manufacturing of sensory structures is further boosted by avoidance of setup or logistical operations.