Studies on the Effect of Laser Shock Peening Intensity on the Mechanical Properties of Wire Arc Additive Manufactured SS316L

This study examines the impact of laser shock peening (LSP) on the mechanical properties, microstructural features, and elemental distribution of stainless steel 316L (SS316L) produced using wire arc additive manufacturing (WAAM). The investigation focuses on significant changes in mechanical behavior, surface topography, and porosity following LSP treatment, comparing these results to the untreated condition. LSP treatment significantly enhanced the ultimate tensile strength (UTS) and yield strength (YS) of WAAM-fabricated SS316L samples. The UTS of the as-manufactured WAAM specimen was 548 MPa, which progressively increased with higher LSP intensities to 595 MPa for LSP-1, 613 MPa for LSP-2, and 634.5 MPa for LSP-3, representing a maximum improvement of 15.8%. The YS showed a similar trend, increasing from 289 MPa in the as-manufactured specimen to 311 MPa (LSP-1) and 332 MPa (LSP-2), but decreasing to 259 MPa for LSP-3, indicating over-peening effects. Microstructural analysis revealed that LSP induced severe plastic deformation and reduced porosity from 14.02% to 4.18%, contributing to the improved mechanical properties. Energy dispersive spectroscopy (EDS) analysis confirmed the formation of an oxide layer post-LSP, with an increase in carbon (C) and oxygen (O) elements and a decrease in chromium (Cr) and nickel (Ni) elements on the surface, attributed to localized pressure and heat impacts. LSP-treated samples exhibited enhanced mechanical performance, with higher tensile strengths and improved ductility at higher laser intensities. This is due to LSP effectively enhancing the mechanical properties and structural integrity of WAAM-fabricated SS316L, reducing porosity, and refining the microstructure. These improvements make the material suitable for critical applications in the aerospace, automotive, and biomedical fields

Standalone and Interconnected Analysis of an Independent Accumulator Pressure Compressibility Hydro-Pneumatic Suspension for the Four-Axle Heavy Truck

This paper has proposed a new hydro-pneumatic damper, allowing independent accumulator pressure compressibility from the chamber pressure which enhances isolation performances due its lower F-V hysteresis effect at moderate velocities. The system utilizes the generic hydraulic damper with two hydro-pneumatic accumulators and four check valves in its design. To evaluate the active suspension capability of proposed damper effectiveness, a 22-degrees-of-freedom (DOF), four-axle truck model is integrated with a hydraulic control valve, which is built in an LMS-AME sim environment. Then, the model is exported as an S-function into Matlab/Simulink co-simulation platform for the hydraulic servo-valve control input of a model predictive control (MPC) and proportional-integral-derivative (PID) output signal. Simulation results show that the MPC and an additional supply of fluid to the proposed damper provide better performances and an adaptive damping capability is established. This work also showcases the development and results of a roll interconnected suspension study to assess the proposed damper characteristics when it is interconnected. The various advantages of the proposed-HPIS system over the well-known hydraulic interconnected system (HIS) and hydro-pneumatic interconnected suspension (HPIS) system are studied

A Decode and Forward Protocol for Two-Stage Gaussian Relay Networks

Abstract—We propose a multihopping decode and forward relaying protocol for two-stage Gaussian relay networks with half-duplex nodes. We analytically show that the achievable rates in suitably defined strong and weak interference regimes are close to the cut-set bound. Index Terms—Two-stage relay network, decode and forward protocol, half-duplex relays. I

Hydraulic control valve integrated novel semi active roll resistant interconnected suspension with vertical and roll coordinated control scheme

Though the interconnected active suspension enhances the performances of roll dynamics along with the primary functions of passive suspension, it requires an external pressurized fluid supply. Also, higher energy is required to attain the variable damping force in an active interconnected system. Therefore, this research attempts to control the vehicle roll without an external fluid supply by novel semi-active based roll-resistant interconnected suspension system (SARR-HIS). The variable damping is achieved by utilizing the pressure developed in the chambers and hydraulic control valve (HCV), while the suspension compresses. The amount of the flow passes through the HCV is controlled by a model predictive controller. In addition, GA based optimization were performed to identify the optimal passive roll-resistant hydraulic interconnected suspension (PRR-HIS) parameters. For the controller design, vehicle plant model is estimated by the simple identification method in Matlab environment. On the AMESim platform, vehicle with SARR-HIS system integrated model was built and controlled in a co-simulation environment. To assess the effectiveness of the proposed suspension and its control strategy, the anti-roll bar (ARB) integrated passive standalone suspension, optimized PRR-HIS, and proposed SARR-HIS systems are tested under C class road roughness without steer and double lane change maneuver. </jats:p

Multistage relaying using interference networks

Wireless networks with multiple nodes that relay information from a source to a destination are expected to be deployed in many applications. Therefore, understanding their design and performance under practical constraints is important. In this work, we propose and study three multihopping decode and forward (MDF) protocols for multistage half-duplex relay networks with no direct link between the source and destination nodes. In all three protocols, we assume no cooperation across relay nodes for encoding and decoding. Numerical evaluation in illustrative example networks and comparison with cheap relay cut-set bounds for half-duplex networks show that the proposed MDF protocols approach capacity in some ranges of channel gains. The main idea in the design of the protocols is the use of coding in interference networks that are created in different states or modes of a half-duplex network. Our results suggest that multistage half-duplex relaying with practical constraints on cooperation is comparable to point-to-point links and full-duplex relay networks, if there are multiple non-overlapping paths from source to destination and if suitable coding is employed in interference network states.Comment: 5 pages, submitted to ISIT 201

Enhancing the Performance Measures of Abrasive Water Jet Machining on Drilling Acrylic Glass Material

Abrasive Water jet Machining finds its application on extensive range of materials. Both ductile and brittle materials can be machined by this process, but the material removal is different in both the cases, i.e., by Ductile fracture and Brittle fracture respectively. When it comes to brittle materials, conventional machining processes cannot be used due to a number of limitations of the material. Thus, non-conventional machining is a rather preferable choice for brittle materials. However, the quality of machining might vary, as it is dependent on some input parameters such as — Abrasive size, Water jet Pres-sure and Abrasive Flow rate. The quality of the machining for a drilling operation is evaluated based on the hole parameters i.e. — Circularity, Taper ratio, Overcut and Material Removal Rate (MRR). The process parameters are varied in accordance to the desirable outcome to be obtained. Outcomes like MRR and circularity are required to be maximized, whereas Taper ratio and Overcut have to be minimized. The effects and interactions between different parameters on the outcomes are studied using Analysis of Variance (ANOVA)

Enhancing the Performance Measures of Abrasive Water Jet Machining on Drilling Acrylic Glass Material

Abstract Abrasive Water jet Machining finds its application on extensive range of materials. Both ductile and brittle materials can be machined by this process, but the material removal is different in both the cases, i.e., by Ductile fracture and Brittle fracture respectively. When it comes to brittle materials, conventional machining processes cannot be used due to a number of limitations of the material. Thus, non-conventional machining is a rather preferable choice for brittle materials. However, the quality of machining might vary, as it is dependent on some input parameters such as — Abrasive size, Water jet Pres-sure and Abrasive Flow rate. The quality of the machining for a drilling operation is evaluated based on the hole parameters i.e. — Circularity, Taper ratio, Overcut and Material Removal Rate (MRR). The process parameters are varied in accordance to the desirable outcome to be obtained. Outcomes like MRR and circularity are required to be maximized, whereas Taper ratio and Overcut have to be minimized. The effects and interactions between different parameters on the outcomes are studied using Analysis of Variance (ANOVA).</jats:p

Experimental and theoretical investigation of extrusion load for AA6063/SiC extruded composite billet

Because of their great strength and stiffness with regard to their weight, extruded sections are commonly utilized as essential parts in many areas. The investigation focuses on experimental and theoretical analysis of cold extruded aluminium composites. Four types of extrusion die configurations, such as 12:8, 2:4, 12:2, and 8:4, were used to obtain the aluminium composite billets. Aluminium with 5 wt% SiC material was used for the fabrication of Ingot. The theoretical models have been used to determine the extrusion load compared with the experimental value. Moreover, the theoretical model is modified to reflect the relative significance of extrusion parameters in the extrusion process and to provide the actual value of the testing process. Also, the modified model was attributed to developing the equation for evaluating the extrusion load in the intermediate process of extrusion for all the types of extrusion die configurations. The experimentally investigated extrusion load has a 0.81% deviation with the modified model and increased with other theoretical models. Surface morphology analysis was carried out for all configurations of extruded billet components and indicated the surface quality of the extruded billet. </jats:p

Influence of Additive Manufactured Stainless Steel Tool Electrode on Machinability of Beta Titanium Alloy

Additive manufacturing technology provides a gateway to completely new horizons for producing a wide range of components, such as manufacturing, medicine, aerospace, automotive, and space explorations, especially in non-conventional manufacturing processes. The present study analyzes the influence of the additive manufactured tool in electrochemical micromachining (ECMM) on machining beta titanium alloy. The influence of different machining parameters, such as applied voltage, electrolytic concentration, and duty ratio on material removal rate (MRR), overcut, and circularity was also analyzed. It was inferred that the additive manufactured tool can produce better circularity and overcut than a bare tool due to its higher corrosion resistance and localization effect. The additive manufactured tool can remove more material owing to its strong atomic bond of metals and higher electrical conductivity.</jats:p