A process chain for integrating piezoelectric transducers into aluminum die castings to generate smart lightweight structures

Abstract

The application of piezoelectric transducers to structural body parts of machines or vehicles enables the combination of passive mechanical components with sensor and actuator functions in one single structure. This approach has high potential for smart lightweight constructions. To obtain the highest yield, the piezoelectric transducers need to be integrated into the flux of forces (load path) of load bearing structures. Application in a downstream process reduces yield and process efficiency during manufacturing and operation, due to the necessity of a subsequent process step of sensor/actuator application. The die casting process offers the possibility for integration of piezoelectric transducers into metal structures. Particularly favorable are aluminum castings due to their high quality and feasibility for high unit production at low cost. Such molded aluminum parts with integrated piezoelectric transducers enable functions like active vibration damping, structural health monitoring or energy harvesting resulting in significant possibilities of weight reduction, which is an increasingly important driving force of automotive and aerospace industry due to increasingly stringent environmental protection laws. In the scope of those developments, this paper focuses on the entire process chain enabling the generation of lightweight metal structures with sensor and actuator function, starting from the manufacturing of piezoelectric modules over electrical and mechanical bonding to the integration of such modules into aluminum (Al) matrices by die casting. To achieve this challenging goal, piezoceramic sensors/actuator modules, so-called LTCC/PZT modules (LPM) were developed, since ceramic based piezoelectric modules are more likely to withstand the thermal stress of about 700 °C introduced by the casting process. The modules are made of low temperature cofired ceramic (LTCC) tapes with an embedded lead zirconate titanate (PZT) plate and are manufactured in multilayer technique. For joining conducting copper (Cu) wires with the electrode structure of the LPM, a novel laser drop on demand wire bonding method (LDB) is applied, which is based on the melting of a spherical CuSn12 braze preform with a liquidus temperature Tliquid of 989.9 °C providing sufficient thermal stability for a subsequent casting process

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

“…To meet this requirement, various approaches are being developed for manufacturing multifunctional structures in which sensors or actuators are integrated into metallic structures. 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].…”

Sustainable Processes in Aluminium, Magnesium, and Titanium Alloys Applied to the Transport Sector: A Review

“…Regarding innovative trends, it is also interesting to mention a proposal for integrating sensors in lightweight structures to obtain smart structures that provide information about their status [22], or the integration of new technologies in production lines, such as collaborative robots, to optimise the process. With this in mind, in 2017, Cirillo et al [25] proposed the use of collaborative robots (COBOTs) to make the drilling process more efficient and reduce the number of human operations that do not add value.…”

“…They are materials that are widely used in lightweight structural parts for the automotive and aerospace industries [16,20], and the transportation industry is responsible for 35-40% of their total consumption [21]. They are frequently applied through aluminium matrix composites (AMMs); these multi-materials have superior corrosion, wear, electrical, temperature, and elastic modulus properties compared to conventional alloys, and good cost/strength ratios, which make them good candidates for aerospace, automotive, chemical, and transportation applications, where, for example, in the case of the transportation industry, their use is forecast to double by the year 2025 [22,23]. In addition, they are also frequently used associated in multi-material composites with steels [24], FRPs [25], magnesium [17], and titanium [16].…”

Optimal design of watt six-bar transmission mechanism for morphing trailing edge

“…Campanile et al [11] studied aerodynamic deformations and aeroelastic amplification in the belt-rib concept proposed by German Aerospace Center. Smart materials [12][13][14] can be applied in the design of morphing structures, thus reducing the complexity due to the mechanical devices. Bae et al [15] used piezoelectric laminate beam to establish the morphing trailing edge.…”