Enhancement Of Modulus Research Articles

Geosynthetic-stabilized aggregate: quantitative modulus evaluation via Bender Element

Geosynthetics, mainly geogrids and geotextiles, are commonly used to mechanically stabilize unbound aggregate layers in paved road applications. They provide lateral restraint to aggregates to initially increase the layer modulus during construction and minimize its time-dependent decrease under vehicular traffic loading. Different types of geosynthetics may provide different improvement mechanisms and stiffness enhancement levels. Quantitative evaluation of various stabilization geosynthetics is presented herein to compare modulus improvement trends and help incorporate geosynthetic benefits into state-of-the-art mechanistic-empirical (M-E) pavement design procedures. Five geogrids (three extruded, one woven, and one welded) and two geotextiles (one woven and one nonwoven) were studied with a dense graded aggregate in laboratory triaxial testing. Geosynthetics were placed at specimen mid-height and three pairs of Bender Element (BE) sensors were placed at various heights above the geosynthetic to collect shear waves and quantify the degree of mechanical stabilization during resilient modulus testing. While resilient moduli did not distinguish effectiveness of different geosynthetics, shear wave measurements could clearly show local stiffness increases achieved with geosynthetic inclusions. Meanwhile, trends observed in shear modulus profiles at various distances from the geosynthetic, when compared to that of control specimen, properly established the modulus enhancement level achieved in mechanical stabilization with geosynthetics.

Comprehensive Study of Tolanene's Mechanical Properties: Effects of Temperature, Layering, Orientation, and Defects

This study explores the mechanical properties of both single-layered and multi-layered tolanene nanosheets via molecular dynamics (MD) simulations. The effects of critical parameters such as size, temperature, and defects on the mechanical behavior of armchair and zigzag configurations of single-layer Tolanene nanosheets are analyzed. Key mechanical properties, including Young's modulus, ultimate stress, fracture stress, and fracture strain, are evaluated based on the stress-strain curve. It is observed that the zigzag configuration exhibits a higher Young's modulus compared to the armchair configuration. However, the armchair structure shows greater ultimate stress than the zigzag configuration. An increase in temperature or the introduction of vacancy defects leads to a degradation of mechanical properties in both configurations. The sensitivity of Young's modulus to temperature is more pronounced in the zigzag configuration than in the armchair, even though the armchair configuration generally has a higher Young's modulus. Additionally, increasing the number of layers in the nanosheets results in an enhancement of Young's modulus, with the armchair configuration showing more significant improvement than the zigzag configuration. The variation in Young’s modulus with increasing layers is minimal for the zigzag configuration.

Enhanced high-temperature energy storage performance in all-organic dielectric films through synergistic crosslinking of chemical and physical interaction

Advanced electronic devices and energy systems urgently require high-temperature polymer dielectrics that can offer both high discharge energy density and energy storage efficiency. However, the capacitive properties of most polymers sharply deteriorate at elevated temperatures, due to the significant rise in leakage current density and energy loss. Herein, a new design approach is adopted to fabricate high-temperature polyetherimide (PEI) dielectrics with chemical and physical cooperative crosslinking networks, the dual-crosslinked PEI dielectrics are prepared through amine crosslinking agent and the electrostatic interaction of oppositely charged phenyl groups between triptycene (TE) and PEI chain segments. Benefiting from the increased crosslinking sites, the dual-crosslinked PEI films achieve the simultaneously enhancement in Tg, modulus and bandgap compared to un-crosslinked and single-crosslinked polymers. Meanwhile, the PEI with dual-crosslinked network displays higher chain packing density, effectively reducing the mean motion pathways of charge carriers and the conduction loss inside polymer dielectric. Consequently, the dual-crosslinked PEI containing 0.25 wt% TE delivers an outstanding discharge energy density of 2.69 J/cm3 and retains excellent cyclability after 100,000 charge–discharge cycles at 200 ℃. Additionally, finite element analysis and molecular dynamics simulation further confirm that less Joule heat and tighter chain structure are formed in the dual-crosslinked polymer dielectric. This research offers a novel methodology to prepare high-performance polymer dielectrics for high-temperature applications.

Green transforming black liquors as a new HCHO scavenger in production eco urea formaldehyde-agro composites

Innovative formaldehyde (HCHO)-scavenger based on black liquor is being developed to achieve eco-friendly low toxic urea formaldehyde (UF) adhesive. This scavenger will enhance the UF adhesive in production of agro-composites, complying with the environmental requirements. The HCHO-scavenger is synthesized from black liquor-based aerogels of various types of black liquors. The performance of the prepared scavengers is assessed via adsorption of HCHO; as well as its beneficial effect on properties of UF adhesive and UF-Palm fiber-composite. In order to produce a composite with mechanical properties and free-HCHO compliance with the standard specifications, the UF-scavenger system is optimized from its behavior. The data evidence the effective behavior of all investigated scavenger to improve bond strength of UF adhesive system (from 8.4 MPa to ∼ 18 MPa); and properties of UF-palm-composites, where the enhancement in modulus of rupture (MOR) and internal bond strength (IB), water repellent, reach to 50 %, 83 % and 7.7 %, respectively. In addition to success in producing eco-composites through reducing the free-HCHO of wood sample from 30.77 to 3.0–12.7 mg/100g with reduction percentages (58.7–90.3 %) exceeded those reported in the literature when carbon and silicon scavengers were used.

Thermo‐mechanical performance of oil palm/bamboo fiber reinforced bio epoxy hybrid composites

AbstractThe aim of this work to fabricate bamboo (B)/oil palm (O) fibers based biocomposites to assess mechanical, thermal and morphological properties. Flexural strength and modulus of hybrid biocomposite (7B:3O) exhibited a higher value (71.18 MPa and 5.24GPa) respectively among all biocomposite samples. On the other hand, pure biocomposite (B) showed a higher impact strength value (6977.8 J/m2) compared to other biocomposites. The results of TGA showed that thermal stability was observed significantly for hybrid biocomposites compared to other samples. In addition, the maximum decomposition temperature values were displayed in the hybrid biocomposite (5B5O), which was 377.82°C. Through DMA, it was likely to find the storage modulus curves (E′), loss modulus (E″) and damping factor (tan δ) for the biocomposites. The E′ showed an increase in the (3736.84 MPa) contrasted to other corresponding samples which were 3121.81 MPa, and 3209.67 MPa for 3B7O MPa and 5B5O samples, respectively. Overall, the results of DMA displayed an enhancement in the storage modulus (E′) in terms of the hybrid biocomposites representing greater stiffness and lower damping factor. SEM micrographs were utilized to understand the fiber bonding and fiber adhesion with the epoxy matrix. Furthermore, it confirmed SEM results that hybrid natural fibers enhance the complete characterisations of bio‐epoxy materials. Additionally, SEM images of the tensile fracture surfaces discovered voids and cracks. Finally, it can be concluded that the selection for the developed hybrid biocomposites provides excellent and economical lightweight biomaterials for automotive, aerospace, contractions and building components.Highlights Green hybrid biocomposites by oil palm/bamboo fiber/bioepoxy resin. Mechanical, thermal, DMA of hybrid composites carried out. Hybrid biocomposite(7B:3O) exhibited higher flexural strength value (71.18 MPa). TGA showed that the biocomposites are thermally further stable. DMA displayed an enhancement in the storage modulus (E′).

Impact of molecular architecture and draw ratio on enhancement of targeted mechanical properties of machine direction oriented polyethylene films produced after blown film extrusion

Conventional multi-material multi-layer flexible packaging offers excellent properties. However, it has recycling challenges, necessitating a shift to mono-material multi-layer flexible packaging for example all-polyethylene (PE) packaging which can be tailored through various synthesis and processing methods for different layers. In this work, we study how the key molecular properties (number-average molecular weight ( Mn), weight-average molecular weight ( M w), molecular weight distribution (MWD), comonomer content (short chain branching)) and machine direction orientation (MDO) process draw ratio (MDX) influence the final morphology and mechanical properties of MDO-PE films which are intended as the outer layer of mono-material all-polyethylene multi-layer flexible packaging. Five PE grades and various blends were extruded and blown into films. Selected blown films were machine direction oriented to obtain the final MDO-PE films. Furthermore, one selected PE blown film was processed at different MDO process draw ratios while keeping other process parameters constant. From the molecular properties point of view, the higher molecular weight fractions provide a higher possibility for uniform stretching whereas lower molecular weight fractions provide a higher natural draw ratio and therefore higher modulus and stiffness enhancement. Further, the results show that increasing MDO process draw ratio leads to more fibrillation and increased crystallinity. Consequently, the tensile modulus and stiffness at the higher draw ratios increase as well and are comparable to conventionally used polymers in outer layers of multilayer flexible packaging. Thus, this work demonstrates that MDO-PE films with enhanced modulus can provide sufficient stiffness for the design of outer layer of mono-material multi-layer all-PE packaging which presents higher potential for mechanical recyclability.

Influence of HEA reinforcement on pulse electric current sintered Aluminium Composites: Microstructure, Density, and nanomechanical properties

This study investigates how different compositions of high-entropy alloys (HEAs), known for their strength and thermal stability, affect the microstructure, density, and nanomechanical properties of aluminium matrix composites produced by pulse electric current sintering (PECS). Commercial aluminium was reinforced with 5%, 7%, and 10% HEA and sintered using PECS. Microstructural analysis showed improved particle bonding and dispersion, resulting in enhanced mechanical properties. Although relative density slightly decreased with higher HEA content, there was a significant enhancement in nanohardness and elastic modulus. The composites exhibited improved resistance to plastic deformation and increased stiffness, thus, highlighting the effectiveness of HEA reinforcement in optimizing aluminium composites for high-strength, lightweight, and advanced engineering applications. These findings offer valuable insights for developing next-generation materials suited to demanding engineering environments.

Recovery of carbon fiber from carbon fiber reinforced polymer waste via microwave molten-carbonate pyrolysis

In recent years, the increased use of carbon fiber-reinforced polymer (CFRP) composites has led to a significant rise in waste production. To address this issue, a recycling method using microwave molten salt pyrolysis-oxidation has been proposed to efficiently process CFRP and obtain regenerated carbon fibers (RCFs) under the combined effect of microwave and Na2CO3/K2CO3/Li2CO3 composite molten salt. The mechanism of microwave molten salt pyrolysis was examined in conjunction with the pyrolysis products (pyrolysis oil and gas), furthermore, the microwave molten salt pyrolysis process was optimized. The causes of the changes in the mechanical characteristics and wettability of carbon fibers (CFs) were additionally investigated and analyzed. The RCFs recovered from previous composite materials were processed into new composite materials and mechanically tested to assess their reusability. The study found that using microwave pyrolysis at 350°C for 10 min followed by oxidation at 450°C for 20 min resulted in recovered carbon fibers (RCFs) that retained 98.81 % of the tensile strength of the virgin carbon fibers (VCFs). Additionally, the RCFs showed a tensile modulus enhancement of 14.70 %, with the recovery ratio of carbon fibers as high as 98.44 %. Pyrolysis generates combustible gases like hydrogen (H2), carbon monoxide (CO), and alkanes, alongside products primarily composed of phenols and aromatic compounds. The recycling method can quickly recover high-performance carbon fibers and valuable pyrolysis by-products from CFRP waste, making them highly valuable for resource recycling and the sustainable development of carbon fiber materials.

Effect of fiber loading on the mechanical, morphological, and dynamic mechanical characteristics of Calamus tenuis fiber reinforced epoxy composites

AbstractThis research delves into incorporating Calamus tenuis fibers as reinforcing material in polymer composites, conducting a thorough analysis of their viscoelastic, mechanical, and morphological attributes. Employing the hand layup method, Calamus tenuis fiber‐reinforced epoxy composites were crafted across a range of fiber loadings from 0 to 25 wt% with 5 wt% increments. Results highlight significant enhancements in mechanical attributes upon the incorporation of Calamus tenuis fibers into the matrix. Notably, the composite with 10 wt% Calamus tenuis fibers emerges as the top performer, showcasing unparalleled mechanical strength compared to neat epoxy. It achieves the highest tensile strength (21.08 ± 1.03 MPa) and tensile modulus (2.84 ± 0.09 GPa), along with the utmost flexural strength (63.31 ± 1.05 MPa) and flexural modulus (3.12 ± 0.16 GPa). Furthermore, it demonstrates remarkable impact strength (9.40 ± 0.40 J/cm2), emphasizing its resilience. Scanning electron microscopy (SEM) analysis confirms enhanced fiber‐matrix adhesion in the 10 wt% composite. Additionally, dynamic mechanical analysis (DMA) results reveal enhancements in storage and loss modulus, with the 10 wt% composites exhibiting the highest values. However, the damping factor decreases with the inclusion of Calamus tenuis fibers. Overall, a 10 wt% fiber loading is deemed ideal for enhancing the mechanical and dynamic properties of epoxy composites.Highlights Utilized Calamus tenuis fibers as reinforcing materials in epoxy composites. Investigated the mechanical, morphological, and viscoelastic properties. Calamus tenuis fibers boost epoxy composite mechanical traits significantly. SEM confirms improved fiber‐matrix adhesion in 10 wt% composite. DMA highlights elevated storage and loss modulus in 10 wt% composites.

Fabrication of kenaf fiber reinforced boron carbide fillers embedded epoxy matrix composite – An antimicrobial and structural analysis

This study investigates the incorporation of boron carbide (B4C) filler particulates into a kenaf fiber-reinforced epoxy matrix to explore its potential in lightweight applications, focusing on antimicrobial effectiveness, mechanical integrity, thermal properties, and microstructural characteristics. The composite material was formulated by blending varying seven different concentrations of boron carbide (0–50 g) and kenaf fibers (KFs) with an epoxy resin, aiming to achieve a balance between mechanical strength and minimal weight. Antimicrobial test revealed that the composite material, consisting of kenaf fiber reinforced with B4C particulates, exhibited significant antibacterial activity against common pathogens. Mechanical testing indicated that the addition of boron carbide and kenaf fibers significantly improved the tensile strength and flexural rigidity of the composites. Specifically, enhancements in tensile strength and flexural modulus were quantitatively analyzed, showing notable increases compared to the base epoxy resin. Scanning Electron Microscopy (SEM) was employed to examine the fracture surfaces following mechanical testing, revealing improved interfacial bonding between the kenaf fibers and the epoxy matrix due to the presence of boron carbide. This microscopic analysis also highlighted areas where stress distribution was optimized, contributing to the composite's enhanced mechanical properties.

Conductive, injectable, and self-healing collagen-hyaluronic acid hydrogels loaded with bacterial cellulose and gold nanoparticles for heart tissue engineering

The increasing demand for advanced biomaterials in nerve tissue engineering presents numerous challenges due to the complexity of nerve tissues and the need for materials that can accurately replicate their intricate structure and function. In response, this study introduces a novel injectable hydrogel that is thermosensitive, self-healing, and conductive, offering promising potential for heart and nerve tissue engineering applications. The hydrogel is based on collagen and hyaluronic acid functionalized with 3-aminopropyl-triethoxysilane (APTES)-grafted oxidized bacterial cellulose and gold nanoparticles (~50 nm). Rheological analysis reveals a substantial enhancement in the elastic modulus of the collagen-hyaluronic acid matrix with the incorporation of bacterial cellulose/gold nanoparticles, improving by an order of magnitude at 1 % strain. This improvement comes with a slight decrease in gelation temperature, from 36 °C to 32 °C. Besides thermo-sensitivity, the nanocomposite hydrogel exhibits a remarkable self-sealing response (about 80 % effectiveness) due to reversible physical crosslinking. Electrical spatial resistance measurements on human embryonic stem cell-derived cardiomyocytes-loaded hydrogels yield a value of ~0.1 S/m, which is suitable for electrical stimulation. In vitro extracellular field potential measurements also affirm the hydrogel's potential as an injectable scaffold for heart tissue engineering, i.e., the electrically stimulated human stem cells exhibit 47 beats per minute with a cell discharge (depletion) of 5.47 μv. A rapid gel formation in the physiological temperature (about 2 min) and high H9C2 cytotoxicity (viability of >90 % after 72 h incubation) is attainable. The developed collagen-based nanocomposite hydrogel offers an injectable, thermosensitive, and self-healing biomaterial platform for nerve or myocardium regeneration.

Creating ultra-strong and recyclable green plastics from marine-sourced alginate-chitosan nanowhisker nanocomposites for controlled release urea fertilizer

In response to the pressing environmental challenge posed by petroleum-derived plastics, the development of green plastics derived from all-biomass nanocomposites offers promising solutions. However, conventional nanocomposites often prioritize enhanced stiffness at the expense of flexibility. We introduce sodium alginate (SA)/chitosan nanowhisker (CSW) nanocomposites, derived entirely from marine-sourced all-biomass, to create ultra-strong and flexible green plastics. Through the synergistic interaction between SA and CSW, these nanocomposites demonstrate simultaneous stiffening and toughening, overcoming the traditional trade-off. Two key mechanisms contribute: geometric reinforcement from the needle-like structure of CSW and electrostatic reinforcement at the interface between oppositely charged CSW and SA. Compared to control SA, the SA/CSW nanocomposites exhibit remarkable enhancements in tensile modulus, strength, and stretchability, by 49%, 85%, and 55%, respectively (7.6 GPa, 223.3 MPa, 14.7%). Cellulose nanocrystals, serving as a control, only stiffen the nanocomposites, adhering to the typical trade-off. Biodegradability in compost can be tailored based on the type of nanofillers. Due to the water resistance of CSW, SA/CSW nanocomposites are proven effective for the controlled release of urea fertilizer in agricultural applications. With recyclability and superior mechanical properties, these marine-sourced green plastics offer a sustainable alternative to conventional plastics, promising significant impact in the eco-plastic industry.

Fabrication of Hybrid Epoxy Composites (Joint Compound Adhesive) for Aluminum Substrate Applications and Their Evaluation for Mechanical Properties.

This research endeavor deals with the development of an epoxy hybrid nanocomposite using aliphatic diglycidyl ether of a bisphenol A (DGEBA) epoxy matrix. The formulation used the stoichiometric ratio of the curing agent and incorporated nanopigments such as zirconium and silica, along with other microfillers. We incorporated Zr and SiO2 nanoparticles and various other additives in the epoxy matrix and ensured homogeneous dispersion by using sonication methodology along with silane as a coupling agent. Aluminum molds were utilized to fabricate dumbbell-shaped ASTM standard samples for the testing of mechanical properties. The adhesive properties were evaluated through standard lap shear tests. Fourier transform infrared spectroscopy was utilized to analyze the cross-linking reaction of the epoxy moiety and the polyamidoamine adduct curing agent. Further characterization using field emission scanning electron microscopy, energy-dispersive spectroscopy, and high-resolution transmission electron microscopy confirmed the presence and uniform dispersion of the fillers and nanopigments. The results showed good enhancements in ultimate tensile strength, yield strength, and elastic modulus of 95.3, 162.1, and 425.4%, respectively, compared to formulations using only SiO2. The addition of ZrO2 and SiO2, along with various microfillers, such as talc and aluminum silicate, led to significant improvements in the mechanical properties. This study demonstrates the synergistic efficiency of combining SiO2 and ZrO2 along with microfillers, such as talc and aluminum silicate, in epoxy resin for diverse applications in the construction industry, where mechanical strength and substrate adhesion are crucial.

Enhancement of Elastic Modulus by TiC Reinforcement in Low-Density Steel

Enhancement of Elastic Modulus by TiC Reinforcement in Low-Density Steel

Synergistic enhancement of modulus and ductility in Mg matrix composites: A new strategy for GNPs&MgOnp and SiCp hybrid reinforcement

SiC particles (SiCp) reinforced magnesium matrix composites (MMCs) exhibit elevated specific stiffness. However, the non-uniform distribution of SiCp and the interfacial cracking between the SiCp and Mg matrix compromise the ductility. This paper presents a novel approach to enhance the modulus and ductility of the MMCs by utilizing in-situ synthesized graphene nanoplatelets (GNPs) and MgO nanoparticles (MgOnp). The in-situ reaction of GNPs and MgOnp (GNPs&MgOnp) conducted at a high temperature (720 °C) demonstrates an improvement in the local agglomeration of SiCp compared to the conventional semi-solid temperature (590 °C). Moreover, the GNPs&MgOnp optimized interfacial structure and transferred the load during plastic deformation, inhibiting stress concentration and crack propagation at the interface of SiCp. The ductility and modulus are enhanced by approximately 70 % and 10 % compared to SiCp/Mg-6Zn composites, demonstrating the effectiveness of the strategy employing micro-nano hybrid reinforcement and synergistic enhancement of ductility and modulus.

Effect of Low Temperature on the Fatigue Crack Propagation Behavior of Underwater Manned Vehicle Rudder Materials in Arctic Environments.

During polar navigation, adverse environmental conditions like cold temperatures, fatigue, and corrosion can affect surface and underwater manned vehicles (UMVs). Understanding the fatigue fracture growth behavior of polar ship steel is crucial for ensuring safety. This study investigates the mechanical properties and fatigue fracture propagation of steel used in underwater vehicle rudders under various low-temperature conditions through experimental research. It compares and analyzes the static mechanical characteristics, fatigue crack growth rate, and fracture morphology of underwater manned vehicle rudder steels at different low temperatures. Findings show enhancements in yield strength, tensile strength, elastic modulus, and fatigue crack propagation life of steel 925A, steel 20#, and their welded parts under low-temperature conditions. The tensile strength of 925A steel, 20# steel, and their welded parts increases by 6.87%, 14.61%, and 12.55%, respectively, as the temperature decreases from 20 to -60 °C. The yield strength also increases by 14.17%, 29.09%, and 15.76%, respectively. Fatigue crack propagation rate experiments were conducted under different constant low-temperature conditions. This study offers direction for future modeling and experimental testing.

Prediction of Mechanical Properties of Nano-Clay-Based Biopolymeric Composites.

An understanding of the mechanical behavior of polymeric materials is crucial for making advancements in the applications and efficiency of nanocomposites, and encompasses their service life, load resistance, and overall reliability. The present study focused on the prediction of the mechanical behavior of biopolymeric nanocomposites with nano-clays as the nanoadditives, using a new modeling and simulation method based on Comsol Multiphysics software 6.1. This modeling considered the complex case of flake-shaped nano-clay additives that could form aggregates along the polymeric matrix, varying the nanoadditive thickness, and consequently affecting the resulting mechanical properties of the polymeric nanocomposite. The polymeric matrix investigated was biopolyamide 11 (BIOPA11). Several BIOPA11 samples reinforced with three different contents of nano-clays (0, 3, and 10 wt%), and with three different nano-clay dispersion grades (employing three different extrusion screw configurations) were obtained by the compounding extrusion process. The mechanical behavior of these samples was studied by the experimental tensile test. The experimental results indicate an enhancement of Young's modulus as the nano-clay content was increased from 0 to 10 wt% for the same dispersion grades. In addition, the Young's modulus value increased when the dispersion rate of the nano-clays was improved, showing the highest increase of around 93% for the nanocomposite with 10 wt% nano-clay. A comparison of the modeled mechanical properties and the experimental measurements values was performed to validate the modeling results. The simulated results fit well with the experimental values of Young's modulus.

Strain-independent auxetic metamaterials inspired from atomic lattice

Metamaterials with strain-independent negative Poisson's ratio (NPR) and Young's modulus are essential for the applications with extreme loading conditions. However, strain-independent auxetic metamaterials are rare, and there is a lack of design inspiration for them. In this paper, we present a novel auxetic metamaterial inspired from the atomic lattice with strain-independent NPR. The novel NPR properties due to the unique atomic lattice keep valid when scaling up by 6 orders of magnitude to macroscopic metamaterials, with the similar deformation mechanism. The NPR and Young's modulus keep constant with increasing loading strain. These strain-independent auxetic effects are robust with various designable geometric parameters in wide ranges. Furthermore, the geometric parameters optimization for the auxetic metamaterial is conducted through developing the matrix displacement method. An optimized metamaterial is achieved with 3 times enhancement of auxeticity and 2 orders of magnitude enhancement of Young's modulus, compared to the initio architectures. This work provides a wealth of inspirations from atomic lattice in nature to design strain-independent macroscale auxetic metamaterials.

An All-in-One Array of Pressure Sensors and sEMG Electrodes for Scoliosis Monitoring.

Scoliosis often occurs in adolescents and seriously affects physical development and health. Traditionally, medical imaging is the most common means of evaluating the corrective effect of bracing during treatment. However, the imaging approach falls short in providing real-time feedback, and the optimal corrective force remains unclear, potentially slowing the patient's recovery progress. To tackle these challenges, an all-in-one integrated array of pressure sensors and sEMG electrodes based on hierarchical MXene/chitosan/polydimethylsiloxane (PDMS)/polyurethane sponge and MXene/polyimide (PI) is developed. Benefiting from the microstructured electrodes and the modulus enhancement of PDMS, the sensor demonstrates a high sensitivity of 444.3 kPa-1 and a broad linear detection range (up to 81.6kPa). With the help of electrostatic attraction of chitosan and interface locking of PDMS, the pressure sensor achieves remarkable stability of over 100000 cycles. Simultaneously, the sEMG electrodes offer exceptional stretchability and flexibility, functioning effectively at 60% strain, which ensures precise signal capture for various human motions. After integrating the developed all-in-one arrays into a commercial scoliosis brace, the system can accurately categorize human motion and predict Cobb angles aided by deep learning. This study provides real-time insights into brace effectiveness and patient progress, offering new ideas for improving the efficiency of scoliosis treatment.

Dynamic Responses of Human Skin and Fascia to an Innovative Stimulation Device-Shear Wave Stimulation.

Exposure to mechanical stimuli such as pressure and stretching prompts the skin to undergo physiological adaptations to accommodate and distribute applied forces, a process known as mechanotransduction. Mechanotherapy, which leverages mechanotransduction, shows significant promise across various medical disciplines. Traditional methods, such as massage and compression therapy, effectively promote skin healing by utilizing this mechanism, although they require direct skin contact. This study introduces a novel contactless modality, Shear Wave Stimulation (SWS), and evaluates its efficacy compared to traditional massage in eliciting responses from human skin and fascia. Fifteen healthy volunteers received SWS, while another fifteen volunteers received massage. Tests of skin mechanical properties revealed significant enhancements in skin shear modulus for both methods, showing an increase of approximately 20%. Additionally, deformation analysis of ultrasound images showed distinct responses of the skin and fascia to the two stimuli. SWS induced extension in the dermis (∼18%), hypodermis (∼16%), and fascia (∼22%) along the X and Y axes. In contrast, massage compressed the skin layers, reducing the dermis by around 15% and the hypodermis by about 8%, while simultaneously stretching the superficial fascia by approximately 8%. The observed extension across the entire skin with SWS highlights its potential as a groundbreaking contactless approach for promoting skin healing. Furthermore, the differing responses in blood flow reaffirm the distinct stimulation modes of SWS and massage. These findings establish a foundation for future innovative skin therapy modalities.