scholarly journals Stress-Shot-Peened Leaf Springs Material Analysis through Nano- and Micro-Indentations

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4795
Author(s):  
Maria Pappa ◽  
Georgios Savaidis ◽  
Nikolaos Michailidis
Keyword(s):  
Material Properties ◽  
High Performance ◽  
Mechanical Performance ◽  
Microstructural Analysis ◽  
Simulation Models ◽  
Elastoplastic Material ◽  
The Core ◽  
Leaf Springs ◽  
Stress Changes ◽  
Bending Stresses

Heat-treated and shot-peened lightweight steels with demanding requirements for durability are applied in high-performance automotive leaf springs. Due to their heat-treatment they exhibit degraded properties in the surface-near area compared to the core. This area, which may extend until 300 μm from the surface to the core, experiences the highest bending stresses at operation. The microstructure in the surface and sub-surface layers determines the mechanical performance as well as the wear resistance. The present study refers to the material properties of a stress shot-peened 51CrV4 steel at various depths from the surface. The effect of the manufacturing process has been captured both by Vickers micro-hardness measurements and nanoindentation. The latter combined with a Fine Element Method (FEM)-based algorithm enables the determination of variations in the material’s stress–strain curves over the affected layers, which translate to internal stress changes. The nanoindentation technique has been applied here successfully for the first time ever on leaf springs. The combination of microstructural analysis, microhardness and nanoindentation captures the changes of the treated material, offering insights on the material characteristics, and yielding accurate elastoplastic material properties for local, layered-based analysis of the components’ mechanical performance at operational loading scenarios, i.e. in the framework of stress shot-peening simulation models.

scholarly journals Effects of nano-silica on mechanical performance and microstructure of ultra-high performance concrete

Cerâmica ◽  
2017 ◽  
Vol 63 (367) ◽  
pp. 387-394 ◽  
Author(s):  
T. M. Mendes ◽  
W. L. Repette ◽  
P. J. Reis
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Microstructural Analysis ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
X Ray

Abstract The use of nanoparticles in ultra-high strength concretes can result in a positive effect on mechanical performance of these cementitious materials. This study evaluated mixtures containing 10 and 20 wt% of silica fume, for which the optimum nano-silica content was determined, i.e. the quantity of nano-silica that resulted on the higher gain of strength. The physical characterization of raw materials was done in terms of particle size distribution, density and specific surface area. Chemical and mineralogical compositions of materials were obtained through fluorescence and X-ray diffraction. The mechanical performance was evaluated by compressive strength, flexural strength and dynamic elastic modulus measurements. The microstructural analysis of mixtures containing nano-silica was performed by X-ray diffraction, thermogravimetry, mercury intrusion porosimetry and scanning electron microscopy. Obtained results indicate an optimum content of nano-silica of 0.62 wt%, considering compressive and flexural strengths. This performance improvement was directly related to two important microstructural aspects: the packing effect and pozzolanic reaction of nano-silica.

KEMPER CuSn6

Alloy Digest ◽  
2018 ◽  
Vol 67 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Electronics Industry ◽  
Bend Strength ◽  
Leaf Springs ◽  
Machine Parts

Abstract Alloy CuSn6 (UNS C51900) is a high-performance copper alloy. Typical uses include components for the electronics industry such as connector springs, relays, leaf springs, and switches as well as machine parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength. It also includes information on corrosion resistance as well as forming and joining. Filing Code: Cu-873. Producer or source: Gebr. Kemper GmbH + Company KG Metallwerke.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

scholarly journals Durability Study on High-Performance Fiber-Reinforced Mortar under Simulated Wastewater Pipeline Environment

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3781
Author(s):  
Tianyu Wang ◽  
Yahong Zhao ◽  
Baosong Ma ◽  
Cong Zeng
Keyword(s):  
Mass Loss ◽  
Pore Volume ◽  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Economic Losses ◽  
Structural Deterioration ◽  
Simulated Wastewater ◽  
Corrosive Environments

The acid–alkaline-inducd corrosive environments inside wastewater concrete pipelines cause concrete structural deterioration and substantial economic losses all over the world. High-performance concrete/mortar (HPC) was designed to have better resistance to corrosive environments, with enhanced service life. However, the durability of HPC in wastewater pipeline environments has rarely been studied. A high-performance mortar mixture (M) reinforced by supplemental materials (including fly ash and silica fume) and polyvinyl alcohol (PVA) fibers, together with a mortar mixture (P) consisting of cement, sand and water with similar mechanical performance, were both designed and exposed to simulated wastewater pipeline environments. The visual appearance, dimensional variation, mass loss, mechanical properties, permeable pore volume, and microstructure of the specimens were measured during the corrosion cycles. More severe deterioration was observed when the alkaline environment was introduced into the corrosion cycles. Test results showed that the M specimens had less permeable pore volume, better dimensional stability, and denser microstructure than the P specimens under acid–alkaline-induced corrosive environments. The mass-loss rates of the M specimens were 66.1–77.2% of the P specimens after 12 corrosion cycles. The compressive strength of the M specimens was 25.5–37.3% higher than the P specimens after 12 cycles under corrosive environments. Hence, the high-performance mortar examined in this study was considered superior to traditional cementitious materials for wastewater pipeline construction and rehabilitation.

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

Test and Study on Green High-Performance Marine Concrete Containing Ultra-Fine Limestone Powder

2013 ◽  
Vol 368-370 ◽  
pp. 1112-1117
Author(s):  
Jin Hui Li ◽  
Liu Qing Tu ◽  
Ke Xin Liu ◽  
Yun Pang Jiao ◽  
Ming Qing Qin
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
Mechanical Performance ◽  
Chloride Ion ◽  
Limestone Powder ◽  
Ion Permeability ◽  
High Quality ◽  
Cracking Resistance ◽  
Slag Powder ◽  
Marine Concrete

In order to solve the environment pollution of limestone powder during production of limestone manufactured sand and gravel and problem of lack of high quality fly ash or slag powder in ocean engineering, ultra-fine limestone powder was selected for preparation of green high-performance marine concrete containing fly ash and limestone powder and that containing slag powder and limestone powder for tests on workability, mechanical performance, thermal performance, shrinkage, and resistance to cracking and chloride ion permeability. And comparison was made between such green high-performance concrete and conventional marine concrete containing fly ash and slag powder. Moreover, the mechanism of green high-performance marine concrete was preliminary studied. Results showed that ultra-fine limestone powder with average particle size around 10μm had significant water reducing function and could improve early strength of concrete. C50 high-performance marine concrete prepared with 30% fly ash and 20% limestone powder or with 30% slag powder and 30% limestone powder required water less than 130kg/m3, and showed excellent workability with 28d compressive strength above 60MPa, 56d dry shrinkage rate below 300με, cracking resistance of grade V, 56d chloride ion diffusion coefficient not exceeding 2.5×10-12m2/s. Mechanical performance and resistance to chloride ion permeability of limestone powder marine concrete were quite equivalent to those of conventional marine concrete. But it had better workability, volume stability and cracking resistance. Moreover, it can serve as a solution to the lack of high quality fly ash and slag powder.

Fiber element modeling of circular double-skin concrete-filled stainless-carbon steel tubular columns under axial load and bending

2022 ◽  
pp. 136943322110651
Author(s):  
Mizan Ahmed ◽  
Qing Quan Liang ◽  
Ahmed Hamoda
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
High Performance ◽  
Mechanical Performance ◽  
Axial Strain ◽  
High Strength ◽  
Offshore Structures ◽  
Numerical Results ◽  
Beam Columns ◽  
Double Skin

Circular concrete-filled double-skin steel tubular (CFDST) columns with external stainless-steel are high-performance composite columns that have potential applications in civil construction including the construction of offshore structures, bridge piers, and transmission towers. Reflecting the limited research performed on investigating their mechanical performance, this study develops a computationally efficient fiber model to simulate the responses of short and slender beam-columns accounting for the influences of material and geometric nonlinearities. Accurate material laws of stainless steel, carbon steel, and confined concrete are implemented in the mathematical modeling scheme developed. A new solution algorithm based on the Regula-Falsi method is developed to maintain the equilibrium condition. The independent test results of short and slender CFDST beam-column are utilized to validate the accuracy of the theoretical solutions. The influences of various column parameters are studied on the load-axial strain [Formula: see text] curves, load-lateral deflection [Formula: see text] curves, column strength curves, and interaction curves of CFDST columns. Design formulas are suggested for designing short and beam-columns and validated against the numerical results. The computational model is found to be capable of simulating the responses of CFDST short and slender columns reasonably well. Parametric studies show that the consideration of the concrete confinement is important for the accuracy of the prediction of their mechanical responses. Furthermore, high-strength concrete can be utilized to enhance their load-carrying capacity particularly for short and intermediate slender beam-columns. The strengths of CFDST columns computed by the suggested design model are in good agreement with the test and numerical results.

TRU Recycling Options for Environmentally Friendly and Proliferation-Resistant Nuclear Fuel Cycle of FBR

2010 ◽  
Author(s):  
Sidik Permana ◽  
Mitsutoshi Suzuki
Keyword(s):  
High Performance ◽  
Fuel Cycle ◽  
Operation Time ◽  
Nuclear Nonproliferation ◽  
High Level Waste ◽  
Minor Actinide ◽  
Spent Fuel ◽  
Closed Fuel Cycle ◽  
The Core ◽  
High Level

The embodied challenges for introducing closed fuel cycle are utilizing advanced fuel reprocessing and fabrication facilities as well as nuclear nonproliferation aspect. Optimization target of advanced reactor design should be maintained properly to obtain high performance of safety, fuel breeding and reducing some long-lived and high level radioactivity of spent fuel by closed fuel cycle options. In this paper, the contribution of loading trans-uranium to the core performance, fuel production, and reduction of minor actinide in high level waste (HLW) have been investigated during reactor operation of large fast breeder reactor (FBR). Excess reactivity can be reduced by loading some minor actinide in the core which affect to the increase of fuel breeding capability, however, some small reduction values of breeding capability are obtained when minor actinides are loaded in the blanket regions. As a total composition, MA compositions are reduced by increasing operation time. Relatively smaller reduction value was obtained at end of operation by blanket regions (9%) than core regions (15%). In addition, adopting closed cycle of MA obtains better intrinsic aspect of nuclear nonproliferation based on the increase of even mass plutonium in the isotopic plutonium composition.

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