An experimental study has been performed to investigate the effects of sustained hydrostatic depth pressure saltwater immersion coupled with low temperatures on the mechanical and structural integrity properties of additively manufactured (AM) polymer and resin-based materials. The materials that were evaluated in the study were produced by both the material extrusion and Vat Photopolymerization printing methods. The material extrusion materials consisted of Stratasys ULTEM 9085 and Markforged Onyx, and the Vat Photopolymerization material was Accura ClearVue resin. Water immersion was conducted with 3.5

This research investigated the kinematics and vibrational performance of McKibben-type artificial soft fabric muscles (ASFMs). The ASFMs are constructed of High-Performance Fibers (HPF) encompassing an oversized, pleated, nonstructural fluid bladder. These ASFMs have potential applications for the launch, recovery, positioning and control of undersea and surface vehicles and interface platforms. The vibrational characteristics of ASFMs constructed of both glass and aramid braid materials were evaluated experimentally by exposing a fluid-pressurized ASFM to flow-induced vibration (FIV) and measuring the response.

The effects of salt water exposure at deep ocean depth pressures when coupled with low temperatures on the material characteristics of three unique additively manufactured polymers has been investigated through a detailed experimental approach. The polymers in the study were manufactured utilizing both Vat Photopolymerization and Material Extrusion printing techniques. The Material Extrusion process was utilized to produce material specimens of Stratasys ULTEM 9085 and Markforged Onyx while the Vat Photopolymerization process was used to produce specimens of Accura ClearVue. The ULTEM 9085 and Markforged Onyx are filament based polymers and the ClearVue is a liquid based resin. The specimens were first submerged in a high pressure, salt water bath of 3.5% NaCl solution at 34.5 MPa (5000 lb/in2) for a total exposure time of 60 days to determine the water absorption characteristics. Subsequent to the salt water exposure at high pressure, the specimens were evaluated to determine changes in tension, compression, flexure, and in-plane fracture properties. To determine the effects of water saturation and low temperature coupling, the mechanical testing was performed at temperatures of 20°C, 0°C and -20°C in both dry and saturated conditions. Additionally, non-destructive testing in the form of TeraHertz and FIRT imaging was conducted to analyze the physical material changes through the thickness of the material due to the saline water absorption. To quantify the change in material storage and loss moduli properties, Dynamic Mechanical Analysis (DMA) characterization was performed on each of the AM polymers in dry and saturated states. The DMA testing also quantified changes in the Glass Transition Temperature because of salt water exposure. In summary, The current study investigates the effects of coupled long term/high pressure salt water exposure with low temperatures on the mechanical and material characteristics of three unique AM polymers by: (1) immersing the materials in a salt water solution at 34.5 MPa for 60 days, (2) Conducting post exposure mechanical testing on the materials at 0°C and -20°C with comparisons to 20°C testing on dry specimens, and quantifies changes in material properties through DMA experiments. The results from all testing in the study show that high pressure salt water exposure when coupled with low temperatures has unique effects on each of the materials considered in the study and careful consideration to each parameter must be given based on the material type when components will be employed in marine operations.

The objectives of this work are threefold: (1) quantify the effects that print parameters have on the mechanical performance of parts produced by a novel vat photopolymerization technology called Low Force Stereolithography (LFS), (2) demonstrate the relative impact of each print parameter on part performance through Signal-to-noise ratio (S/N) analysis and (3) propose theoretical parameter schemas to optimize part performance. This work presents the mechanical properties of LFS parts with respect to distinct LFS print parameters, namely print orientation (PO), print layer thickness (LT), post-print cure time (CM), and post-print cure temperature (CT) at three (3) levels apiece. To date, LFS has been largely unstudied; however, as a novel approach with unique engineering material availability, it is important to quantify. Using D638-22, it was found that the Segment Modulus (SE), Ultimate Strength (US), percent elongation (%e), Poisson’s ratio (ν) and Toughness (T) varied greatly across the nine (9) distinct sample families designed for study. Specifically, SE, US, %e, ν, and T achieved a minimum/maximum of 331/463 ksi, 4.39/9.07 ksi, 1.20/3.55%, .377/.450 and .033/.200 ksi, respectively, depending on the parameters chosen. This wide range of property data is important to quantify and couple to parameter schemas if LFS is to be implemented as a viable approach to manufacture end-use or provisional tooling. Furthermore, it is essential to understand the relationship between a given property and a specific parameter. S/N plots were used to quantify this relationship. The results indicate that all print parameters – but most notably PO – influence the mechanical performance of LFS parts.

A detailed experimental study is performed on the piezo-resistive damage sensing capability of electrically conductive carbon fiber and carbon nanotube-infused glass fiber composites after freshwater and saltwater ingression under quasi-static tension and under low temperatures. The electrical resistance is recorded via a two-point probe measurement technique for carbon fiber and a four-point probe measurement technique for glass fiber. The carbon fiber composites on average absorbed 1.7% of their initial mass as either freshwater or saltwater. The glass fiber composites absorbed 2.1% on average of their initial mass as freshwater or saltwater. Mechanical and electrical properties of carbon fiber composites showed a dependency on both water ingression and testing temperature. Water-infused carbon fiber composites exhibited a unique electrical behavior where, after severe delamination the frayed lamina fibers could bridge the delamination and regenerate lost electrical connections. Lower temperatures allowed more severe delamination to occur within the composite. The glass fiber composites infused with 0.5% by weight (wt) and 95% purity carbon nanotubes were not conductive and did not detect internal damages.

This research investigated the time-dependent stress relaxation and creep performance of McKibben-type artificial soft fabric muscles (ASFMs). The ASFMs are constructed of High Performance Fibers (HPF) encompassing an oversized, pleated, nonstructural fluid bladder. These ASFMs have potential applications for the launch, recovery, positioning and control of undersea and surface vehicles and interface platforms. Glass and aramid braid materials were evaluated analytically and experimentally. The analytical model utilized a modified General Maxwell Model to capture the stress relaxation and creep behaviors of ASFMs. This model was then compared with the experimental results.

The pursuit of increased autonomy for undersea and surface vehicles presents challenges for their launch, recovery, positioning and control (LRP&C). Traditional rigid handling and actuator systems are often volume constrained and can limit payloads capacities and operational effectiveness. The need to innovate high capacity and compact actuation technologies is intensified by increasing demands for rapid deployability and stowability, scalability, adaptability, temporary buoyancy and connectivity across the undersea and surface domains. On-demand inflatable and compactable soft actuators may provide unique solutions with robustness needed to operate in extreme underwater environments. This preliminary research investigated the mechanical behaviors, load and stroke capacities, end termination designs and limitations of artificial soft fabric muscles (ASFMs), also known as McKibben muscles, constructed of High Performance Fibers (HPF) for potential launch, recovery, positioning and control of undersea and surface vehicles and interface platforms. Computational mechanics and experimental tests were performed on air-inflated ASFMs constructed of braided fabrics to evaluate their quasi-static behaviors. Both glass and aramid braid materials were studied for a range of diameters and lengths. The computational models supported the fluid/structure interactions by using an Equation of State (EOS) that governed the thermomechanical behaviors of the internal air during volumetric expansion and axial contraction of the ASFMs.

This research study investigated the flame-smoke-toxicity (FST) behaviors of water-based, nontoxic, and lightweight coating materials as thermal insulation for fiber-reinforced polymer (FRP) composites. Material experiments were conducted to evaluate the thermal and mechanical performances of these materials in two forms, namely as coatings on and matrices in structural composites. The present research evaluated the thermal protection performance of a nontoxic, aqueous coating material (SBS-1607[1]) demonstrated on carbon- and glass fiber-reinforced epoxy composites. The SBS-1607 coating is a ceramic particulate-filled thermoset material. The SBS-1607 coating does not produce toxic gases during a burn event and can be used as novel matrix material. The SBS-1607 material was applied as thin coatings on glass fiber (GF) and carbon fiber (CF) epoxy laminated plates. The dimensions of both laminates were 8 inches by 8 inches by 0.197 inches (203.2 mm by 203.2 mm by 5.00 mm). The thickness of the SBS-1607 coating was 0.025 inches (0.67 mm). The maximum temperatures measured from the thermocouple for the uncoated GF and CF samples were 158.7 degrees F and 431.1 degrees F, respectively; the inclusion of the SBS-1607 coating on the GF and CF samples reduced their maximum temperatures to 144.6 degrees F and 227.2 degrees F, respectively. Residual tensile strengths and elastic moduli were used as indicators of thermal damage in the matrix. Visible damage zones were approximated using surface measurements. The coated GF and CF burned composite specimens respectively had 71.85% and 151.14% higher UTS than their uncoated counterpart; the GF and CF specimens with the SBS-1607 coating therefore sustained less damage after the thermal event test.

An experimentally based study has been conducted to quantify the effects of coupled water saturation and low temperatures on the quasi-static and dynamic mechanical behavior of E-Glass and Carbon Epoxy laminates. The relative performance of the materials as a function of water saturation and decreasing temperature was characterized through detailed experiments, specifically in-plane (tensile/compressive) and shear material properties, static and dynamic Mode-I fracture, and impact/flexure after impact strength. In the investigation temperatures from Room Temperature (20 °C) down to arctic seawater and extreme ocean depth conditions (−2 °C) were evaluated. The materials utilized in the study, Carbon/Epoxy and E-glass/Epoxy, are chosen due to their primary interest to the underwater vehicle and marine industry communities. The results of the quasi-static and dynamic material experiments show that all properties are affected by both water saturation and decreasing temperature, although the trends are specific to the property under consideration.

An experimentally based study has been conducted to quantify the effects of coupled water saturation and low temperatures on the quasi-static and dynamic mechanical behavior of E-Glass and Carbon Epoxy laminates. The relative performance of the materials as a function of water saturation and decreasing temperature was characterized through detailed experiments, specifically in-plane (tensile/compressive) and shear material properties, static and dynamic Mode-I fracture, and impact/flexure after impact strength. In the investigation temperatures from Room Temperature (20 °C) down to arctic seawater and extreme ocean depth conditions (−2 °C) were evaluated. The materials utilized in the study, Carbon/Epoxy and E-glass/Epoxy, are chosen due to their primary interest to the underwater vehicle and marine industry communities. The results of the quasi-static and dynamic material experiments show that all properties are affected by both water saturation and decreasing temperature, although the trends are specific to the property under consideration.

An experimental investigation through which the effects of low temperatures on the mechanical, fracture, impact, and dynamic properties of carbon- and E-glass-epoxy composite materials has been conducted. The objective of the study is to quantify the influence of temperatures from 20 °C down to −2 °C on the in-plane (tensile/compressive) and shear material properties, static and dynamic Mode-I fracture characteristics, impact/residual strength, and the storage and loss moduli for the materials considered. The low end of the temperature range considered in the study is associated with Arctic seawater as well as conditions found at extreme ocean depths (2 °C–4 °C). In the investigation, both carbon/epoxy and E-glass/epoxy laminates are evaluated as these materials are of keen interest to the marine and undersea vehicle community. The mechanical characterization of the laminates consists of controlled tension, compression, and short beam shear testing. The Mode-I fracture performance is quantified under both quasi-static and highly dynamic loading rates with additional flexure after impact strength characterization conducted through the use of a drop tower facility. Finally, dynamic mechanical analysis (DMA) testing has been completed on each material to measure the storage and loss moduli of the carbon fiber- and E-glass fiber reinforced composites. The findings of the study show that nearly all characteristics of the mechanical performance of the laminates are both material and temperature dependent.

The mechanical behavior of E-Glass/Epoxy and Carbon Fiber/Epoxy laminates when exposed to low temperature and prolonged submergence operating environments has been investigated through a detailed experimental study. The temperature range which was studied consisted of room temperature (20 °C) to −2 °C, the lowest temperature expected in a submerged ocean environment. Mechanical characterization of each material has been conducted through tensile, compression and short beam shear testing. Additionally, the influence of temperature on the Mode I fracture performance of these laminates was evaluated through Double Cantilever Beam (DCB) tests. Furthermore, a Dynamic Mechanical Analyzer (DMA) was employed to evaluate the structural behavior of these laminates under a range of frequency loading and temperatures. A transition between a matrix-dominated to laminate-dominated responses as functions of strain rate were identified. The current study has resulted in the mechanical characterization of E-Glass/Epoxy and Carbon Fiber/Epoxy laminates as a function of temperature ranging from room temperature to low temperature sea water conditions. The experimental results show a dependence on the static, fracture, and dynamic properties of these laminates.

The primary objectives of the present experimental research were to characterize and compare the interlaminar mode-I fracture toughness, crack growth and flexural stiffness behaviors of Kevlar KM2-Plus® fiber/epoxy matrix laminates constructed of various woven fabric architectures including plain, 2 × 2 twill and 4H satin weaves at cold [− 46 °C (− 50 °F)] and room [20 °C (68 °F)] temperatures. Secondary objectives were to evaluate and compare the fracture and flexure behaviors for two types of woven laminate constructions referred to as consistent and hybridized laminates. Consistent laminates were constructed with a single fabric weave style throughout all plies and were representative of laminate configurations used in traditional composites design. The hybridized laminates incorporated a mixture of different ply weave styles arranged in a strategic manner to achieve functionally-graded attributes and performance benefits such as enhanced damage tolerance, load carrying capacities, residual strengths and dynamic energy absorption/dissipation levels. The experimental results demonstrated that the interlaminar mode-I critical strain energy release rates, GIc and flexure moduli, Eflex were temperature dependent and that the hybridized laminate provided the optimal combination of highest fracture toughness and bending stiffness with the least sensitivity to temperature. The concept of hybridized laminate architectures can be used to mitigate temperature effects on fracture and flexural stiffness in addition to increasing damage tolerance, load carrying capacities, flexure stiffness, fracture toughness, residual strengths and dynamic energy absorption/dissipation.

Three components of a concept robotic fueling system for automatic refueling of vehicles for commercial use were designed and tested. The components of interest were the control system (user interface and logic), vehicle positioning system (sensor system), and the automatic controlled dispensing of fuel (fuel nozzle). Tests on a scaled bench-top vehicle model achieved detection and orientation of the vehicle model in the fuel area as well as location of the modelpsilas fuel port. A test of automated dispensing of fuel was performed on a modified commercial fuel nozzle. Fuel dispensing is initiated by a signal from the control system, and is stopped when an experimentally determined pressure is reached in a venturi tube monitored by the control system, automating a mechanical process implored by fuel nozzles today. It was found that the accuracy and repeatability of the system was compromised by two components of the prototype system; inexpensive IR range sensors and vibrations due to a low end stepper motor.

List of illustrations Acknowledgements Chronology Introduction Walter Pater (1839-1894) 1. Diaphaneite 2. From The Renaissance 3. From 'The Child in the House' 4. From Appreciations 5. Prosper Merimee James Whistler (1834-1903) George Moore (1852-1933) Oscar Wilde (1854-1900) William Butler Yeats (1865-1939) Arthur Symons (1865-1945) Chapter 1 Chapter 2 Chapter 3 Chapter 4 Notes Guide to further reading.