98%
921
2 minutes
20
The aim of this work is to study the effect of high-temperature compaction (HTC) upon the polymorphism and the mechanical behavior of an additively manufactured (AM) carbon fiber-reinforced polyamide (PA6). Different pressure and temperature levels during HTC were tested to determine the overall effect on the mechanical behavior and material crystalline composition. Treated, carbon fiber-reinforced PA6 samples were analyzed using differential scanning calorimetry, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and three-point bending testing. When considered with respect to as-printed samples, an HTC temperature of 190 °C combined with 80 psi pressure resulted in an increased flexural modulus and strength of 47% and 58%, respectively. This increase was attributed to the decrease in AM-induced cracking, voids (both inside and between the beads), and crystalline solid-state transition in the PA6. The effect of pressure and temperature on the crystalline structure was discussed in terms of an increased degree of crystallinity and the amount of α-phase. Therefore, HTC can help overcome some limitations of traditional annealing, which can result in recrystallization-induced cracking which can lead to material embrittlement. The proposed HTC method demonstrates the potential in improving the mechanical behavior of AM thermoplastic composites.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11991067 | PMC |
http://dx.doi.org/10.3390/polym17070922 | DOI Listing |
NPJ Microgravity
September 2025
Department of Mechanical Engineering, UC Santa Barbara, Santa Barbara, CA, USA.
Microgravity experiments on board the International Space Station, combined with particle-resolved direct numerical simulations, were conducted to investigate the long-term flocculation behavior of clay suspensions in saline water in the absence of gravity. After an initial homogenization of the suspensions, different clay compositions were continuously monitored for 99 days, allowing a detailed analysis of aggregate growth through image processing. The results indicate that the onboard oscillations (g-jitter) may have accelerated the aggregation process.
View Article and Find Full Text PDFActa Ortop Mex
September 2025
Departamento de Cirugía Ortopédica y Traumatología, Unidad de Cirugía de Rodilla, Hospital Clínico San Carlos. Madrid, España.
Introduction: the progressive increase in the volume of primary knee arthroplasty surgery is leading in parallel to an increase in revision surgeries, and this trend is expected to continue in the coming decades.
Material And Methods: a retrospective observational study with 203 interventions in 201 patients with knee arthroplasty revision surgery at our center between 2018-2022, including the variables age, sex, body mass index, primary implant, time until revision surgery, mechanical alignment of the primary implant, cause of revision, revision implant, and need for secondary revision.
Results: the average age of the patients was 73.
Med Eng Phys
October 2025
Centre for Simulation in Bioengineering, Biomechanics and Biomaterials (CS3B), Department of Mechanical Engineering, School of Engineering of Bauru, São Paulo State University (UNESP), Bauru, São Paulo, Brazil. Electronic address:
This study aimed to evaluate the near-cortical over-drilling technique on the mechanical behaviour of bone-plate constructs in a rabbit transverse femoral fracture. In vitro biomechanical testing and finite element (FE) models were used for analyses. Rabbits' bones (n = 14) were divided into two groups: G1 - without near-cortical over-drilling, and G2 - with near-cortical over-drilling.
View Article and Find Full Text PDFMed Eng Phys
October 2025
Department of Mechanical Engineering, University of Cape Town, 7701, South Africa; Centre for Research in Computational and Applied Mechanics (CERECAM), University of Cape Town, 7701, South Africa.
The usability and versatility of autoinjectors in managing chronic and autoimmune diseases have made them increasingly attractive in medicine. However, investigations into autoinjector designs require an understanding of the kinematic properties and fluid behaviour during injection. To optimise injection efficiency, this study develops a mathematical and computational fluid dynamics (CFD) model of an IM autoinjector by investigating the effects of viscosity, needle length, needle diameter, and medication volume on the injection process.
View Article and Find Full Text PDFJ R Soc Interface
September 2025
Department of Bioengineering, Imperial College London, London, UK.
Insects and plants have been locked in an evolutionary arms race spanning 350 million years. Insects evolved specialized tools to cut into plant tissue, and plants, to counter these attacks, developed diverse defence strategies. Much previous worked has focused on chemical defences.
View Article and Find Full Text PDF