Integration of Energy Oriented Manufacturing Simulation into the Life Cycle Evaluation of Lightweight Body Parts

Recent years introduced process and material innovations in the design and manufacturing of lightweight body parts for larger scale manufacturing. However, lightweight materials and new manufacturing technologies often carry a higher environmental burden in earlier life cycle stages. The prospective life cycle evaluation of lightweight body parts remains to this day a challenging task. Yet, a functioning evaluation approach in early design stages is the prerequisite for integrating assessment results in engineering processes and thus allowing for a life cycle oriented decision making. The current paper aims to contribute to the goal of a prospective life cycle evaluation of fiber-reinforced lightweight body parts by improving models that enable to predict energy and material flows in the manufacturing stage. To this end, a modeling and simulation approach has been developed that integrates bottom-up process models into a process chain model. The approach is exemplarily applied on a case study of a door concept. In particular, the energy intensity of compression molding of glass fiber and carbon fiber sheet molding compounds has been analyzed and compared over the life cycle with a steel reference part.

Water intake of cellulose materials monitored by positron annihilation lifetime spectroscopy

In this study, for the first time, the experimental technique of positron annihilation lifetime spectroscopy (PALS) has been applied to monitor in situ the microstructural changes of cellulose-based materials, i.e. paper, during water intake. For three different cellulose samples, bleached fine paper without filler, Kraft paper without filler, and a viscose fiber sheet, the mean positron lifetime $$\Delta \tau _{\mathrm {mean}}$$ Δ τ mean showed a strong increase with time in humid atmosphere, but exhibiting different trends depending on the type of sample. For all the cellulose samples investigated, the mean positron lifetime $$\Delta \tau _{\mathrm {mean}}$$ Δ τ mean shows an initial strong increase simultaneously occurring (t<10 h) to the mass increase of the samples due to water intake. Interestingly, the variations of $$\Delta \tau _{\mathrm {mean}}$$ Δ τ mean of the viscose fiber sheet and the Kraft paper sample both show a second increase on longer timescales (t>60 h in humid atmosphere) during which the mass increase of these samples has already been saturated. The results of this study show that by the means of PALS, water transport in paper can be reliably followed over a long timespan and it is even possible to distinguish between different types of cellulose materials. The second stage increase of the mean positron lifetime after long times in humid atmosphere for the Kraft paper sample and the pure viscose sheets even suggest that not only water intake itself can be monitored but also further atomistic processes in the material are accessible.

Damage Location Sensing in Carbon Fiber Composites Using Extrusion Printed Electronics

Structural Health Monitoring (SHM) uses sensors in advanced engineering structures to evaluate integrity and detect damage or deformation affecting structural performance, e.g., cracks, holes, or corrosion. Carbon fiber textile composites are commonly used to reinforce structures such as aircraft, vehicles, or bridges due to their high tensile strength to weight ratio, chemical resistance, and thermal and electrical conductivity. Printing electronics on textiles is a scalable manufacturing technology combining the physical properties of textile materials with the added functionality of electronic elements making them self-sensing. Extrusion printing is a contactless digital printing method to print electrical conductors and passive circuit elements. This paper proposes to combine conventional carbon fiber composite manufacturing processes with printed conductors to create self-sensing carbon fiber textile composites. Damage is sensed by measuring resistance changes in a carbon fiber sheet. Contacts are extrusion printed directly on woven carbon fiber sheets using silver flake ink. A multiplexed Kelvin Double Bridge circuit is the read-out interface. This allows small resistance changes due to damage to be measured in a 4-point configuration. The circuit is connected to the printed contacts on the carbon fiber sheet through multiplexers to detect damage in different locations. This 2D digital sensor can detect the location and size of damage holes for SHM. The resolution of the sensor is controlled by the location and spacing of the silver electrodes, which were studied experimentally and by simulation. The resolution is 26 mm in the current direction and 16 mm in the orthogonal direction. The threshold of detectable damage is 4 mm2. Simulation of the sensor as an isotropic 2D conductor shows good agreement with experimental results for the orthotropic fabric. The resultant sensing device could be integrated into many composite structures as one of its layers or simply printed on the surface to create smart structures.

Physical and Mechanical Properties of Natural Fiber Polyester Laminate Composites

The utilization of natural fibers as reinforcing composites has been widely used. Indonesia has natural fibers abundantly such as ijuk fiber (Arenga pinnata), sisal fiber (Agave Sisalana) and coconut fiber (Cocos Nucifera). Random orientation application of the fiber in composites affected to the lower properties. Therefore, the particular orientation of fibres wereapplied in manufacturing of composite by laminating the short fiber with Polyurethane (PU) adhesive. The size and moisture content (MC) of fiber were 14-15 cm and +10%, respectively. The resin content of PU was 5% by weight of the laminate sheet. The mixture of fibers and PU adhesive was cold pressed for 5 minutes with a thickness of 0.5-1 mm. The laminate sheet of PU-adhesive fibers then mixed with unsaturated polyester resin layer by layer. The fiber laminate composition of composite was varieted such as 1, 2 and 3 layers. The hand layup method was used in the manufacturing of the composite. The physical and mechanical testing like density, moisture content, water absorption, thickness swelling, flexural test (adapt to ASTM D 790 standard) and tensile test (adapt to ASTM D 638 standard) were carried out. In additionmorphological analyses were investigated on composite samples. The results research showed that the net density of polyester, ijuk fiber sheet, sisal fiber sheet, and coconut fiber sheet were 1.21, 0.9, 0.53 and 0.22 g/cm3. The range of composite density was 0.99-1.15 g/cm3. The single layer composite had lower thickness swelling and water absorption than those of the three layers composite. The highest tensile strength of three layers of sisal fiber composite was higher (33.84 MPa) than that of the three layers of coconut fiber composite (12.04 MPa). The flexural strength of double layers composite from fiber sisal was higher (63.16 MPa) than that of three layers coconut fiber composite (28.65 MPa).

One-Step Surface Immobilization of Protein A on Hydrogel Nanofibers by Core-Shell Electrospinning for Capturing Antibodies

Nanofibers (NFs) are potential candidates as filter materials for affinity separation owing to their high liquid permeability based on their high porosity. Multiple and complex processes were conventionally performed to immobilize proteins for modifying NF surfaces. A simple method must be developed to immobilize proteins without impairing their biological activity. Herein, we succeeded in fabricating NFs with a core of cellulose acetate and a shell of hydrophilic polyvinyl alcohol immobilized with staphylococcal recombinant protein A by a one-step process based on core-shell electrospinning. A total of 12.9 mg/cm3 of antibody was captured in the fiber shell through high affinity with protein A immobilized in an aqueous environment of the hydrogel. The maximum adsorption site and dissociation constant evaluated by the Langmuir model were 87.8 µg and 1.37 µmol/L, respectively. The fiber sheet withstood triplicate use. Thus, our NF exhibited high potential as a material for membrane chromatography.