Quasi-static Compressive Properties Research Articles

Quasi-static Deformation Mechanism and Compressive Properties of Aluminum Foams Fabricated by Friction Stir Processing

Quasi-static Deformation Mechanism and Compressive Properties of Aluminum Foams Fabricated by Friction Stir Processing

Dynamic strength differential and Bauschinger effects in an extruded AZ80 magnesium alloy

Quasi-static and high-rate tension and compression properties of an extruded AZ80 Mg alloy rod were investigated at loading rates of 0.001 and 500 s−1. Acquired stress – strain results show that tension and compression plastic deformations of AZ80 rod are asymmetric, and such strength differential effect is dependent of strain rate and loading orientation. Strength differential effect is weakened at 500 s−1 when the sample was loaded along the extrusion direction. Crystal plasticity simulations on the basis of the visco-plastic self-consistent method were performed. Numerical results indicate that the rate and orientation dependency of strength differential effect in AZ80 alloy is related to {101‾2} extension twinning. High-rate tests for pretension, unloading and reverse compression were realized to investigate the dynamic Bauschinger effect. Experimental results show that Bauschinger effect of AZ80 alloy is anisotropic and sensitive to the strain rate. A Bauschinger effect parameter considering strength differential effect was proposed, and it was found that the Bauchinger effect in the extrusion direction is reduced significantly at 500 s−1.

Synergistic effect of microfibers and oriented steel fibers on mechanical properties of UHPC

The study introduces a novel approach to enhance the properties of Ultra-High Performance Concrete (UHPC) through multi-scale synergistic reinforcement using microfibers (0.66mm) and oriented steel fibers (13mm). Various aspects were investigated, including rheological properties, fiber orientation, and fiber pull-out characteristics. Besides, quasi-static mechanical properties and dynamic compressive properties of UHPC were tested and the bending failure was monitored by acoustic emission technique. Experimental results showed that microfiber improved mechanical properties of UHPC matrix and enhanced the fiber-matrix interface. Compressive strength, flexural strength, and toughness of specimens were increased by as high as 25%, 78%, and 55%, respectively, when microfiber was mixed with oriented steel fibers. In terms of dynamic impact performance, UHPC exhibited significant strain rate sensitivity, and microfibers blended with oriented steel fibers resulted in complete damage pattern when subjected to impact loading, and dynamic compressive strength and energy absorption increased by 48.5% and 54.8%, respectively. Therefore, oriented steel fibers coupled with microfibers provide an effective method to enhance the mechanical performance of UHPC.

Quasi-static compressive properties and damage behavior of aluminum matrix syntactic composites with different diameters of glass cenospheres

Aluminum matrix syntactic composites have broad applications, including aerospace, transportation, military industries, and our daily life owing to lightweight and high energy absorption properties. However, its strength and energy absorption capacity still need improvement. In this study, we prepared an aluminum matrix syntactic composite with smaller diameters glass cenospheres. Due to the higher porosity of the glass cenospheres, the density of the syntactic composites ranged from 1.20–1.27 g cm−3, and the strength and energy absorption could reach up to 172.8 MPa and 75.3 MJ m−3, respectively. Combining finite element and in-situ digital image correlation results, the aluminum matrix syntactic composites with large diameter tend to form 45–90° cracks, resulting in a decrease in material strength with increasing glass cenospheres diameter.

Correction to: High-entropy CoCrFeMnNi alloy/aluminide-laminated composites with enhanced quasi-static bending and dynamic compression properties

Correction to: High-entropy CoCrFeMnNi alloy/aluminide-laminated composites with enhanced quasi-static bending and dynamic compression properties

Flexural fatigue behaviour and damage mechanism of polystyrene bead foams—Influence of the foam density

Polystyrene-based bead foams are used in various applications under non-steady loading conditions, ranging from sports protectors to automobiles. However, the cyclic dynamic behaviour of bead foams and the influence of density on flexural fatigue behaviour have not yet been investigated. In this context, an analysis is conducted on both the morphology of the foam beads and the resulting morphology of the moulded parts produced from these beads. Furthermore, the influence of density on the quasi-static compressive and flexural properties was investigated. These results serve as a basis for conducting load-controlled flexural fatigue tests on various dense bead foams.It was found that the density dependence of the mechanical properties in the quasi-static tests follows the power law. In the flexural tests, the predominant damage mechanism is mainly influenced by the foam density but also by the processing.Surprisingly, the specific dissipated energy and stiffness remain constant for different densities until fast progressing failure occurs. Design criteria can be derived from the fatigue results. Under fatigue load, the stress should not exceed 40% of the quasi-static flexural strength, regardless of density.

Combining multiple lattice-topology functional grading strategies for enhancing the dynamic compressive behavior of TPMS-based metamaterials

Recent developments in additive manufacturing technology have enabled the precise fabrication of intricate lattice materials, also known as metamaterials, for various engineering applications, particularly those involving dynamics. Lattice materials, consisting of sheet-based triply periodic minimal surface (TPMS) structures, have been extensively studied for their mechanical performance under quasi-static and dynamic loading conditions. However, less attention has been given to assessing the effect of grading the lattice topological properties for improved compression loading. Consequently, this paper investigates the effect of topology hybridization, periodicity gradation, cell compaction, and combining multiple functional grading strategies on the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. We conducted quasi-static compression tests to evaluate different regular sheet-based TPMS architectures and select the most promising candidates for topology-functional gradation. Subsequently, numerical simulations were performed to analyze the compressive deformation behavior and properties of functionally graded sheet-based TPMS lattice materials alongside the uniform topologies. This test showed that Schwartz Diamond (Du) and Face-centered Rhombic Dodecahedral (FRDu) lattice structures exhibit superior compressive properties in quasi-static conditions. Furthermore, simulations revealed that the lattice topology and grading strategy significantly influence the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. Specifically, the IWPu topology showed a notable increase in compressive strength and energy absorption compared to the other lattice types as the strain rate increased. Hybridizing Du and FRDu topologies produced a strictly layer-wise deformation pattern, resulting in improved quasi-static and dynamic compressive properties compared to the elementary topology. However, a superior uniaxial compressive modulus and strength were achieved by gradually adjusting the periodicity of a single topology (Du) while maintaining the same relative density. The combination of relative density and periodicity gradation led to more desirable deformation behavior while enhancing the overall compressive properties of the metamaterial, regardless of the strain rate.

Effect of heat treatment on mechanical properties of CuCrZr triply periodic minimal surface structures fabricated by selective laser melting

CuCrZr alloy has excellent conductivity, thermal conductivity, friction reduction and abrasion resistance, which can satisfy in different fields. Copper alloy porous structure is a new multifunctional structure with both structural and functional properties. Selective laser melting (SLM) technology has certain advantages for the preparation of periodic porous structures with triply periodic minimal surfaces (TPMS). Under the background of SLM technique, the quasi-static compression properties of Diamond and Gyroid porous structures were studied. The whole deformation of structures was captured by digital camera, and the failure mechanism was analyzed by finite element software. The effects of different heat treatments on the microstructure and mechanical properties of the CuCrZr were studied by scanning electron microscopy and compression tests. The microstructure morphologies show that the number of curved grains decreases and the grains become more regular after heat treatment. Heat treatment can optimize the mechanical properties and energy absorption capacity of the material, which is most obvious at 500 °C. These results indicate that specific heat treatment can improve the stability and predictability of the CuCrZr porous structure.

Quasi-static compressive and cyclic dynamic impact performances of vat photopolymerization 3D printed Al2O3 triply periodic minimal surface scaffolds and Al2O3/Al hybrid structures: Effects of cell size

In this study, Al2O3 triply periodic minimal surface (TPMS) scaffolds with cell sizes of 5 mm, 8.5 mm, and 12 mm were prepared by vat photopolymerization 3D printing, and Al2O3/Al ceramic-metal hybrid structures were subsequently obtained by the metal infiltration of AlSi10Mg. To investigate the influence of cell size on the mechanical properties of vat photopolymerization 3D printed Al2O3 TPMS scaffolds and Al2O3/Al hybrid structures, quasi-static compression and dynamic impact experiments were conducted, and the failure modes during experiments were discussed. It was shown that the quasi-static compression and dynamic impact properties of Al2O3 TPMS scaffolds gradually decreased with the increase in cell size, the compression strength decreased from 15.2 MPa to 8 MPa and the impact strength decreased from 37 MPa to 11 MPa, respectively, which was related to the stress transfer ability of the single cell. In contrast, the effects of cell size on the performance of Al2O3/Al hybrid structures were opposite. When the cell size increased, the quasi-static compression performances of the Al2O3/Al hybrid structure were greatly improved, and the compression strength increased from 175 MPa to 250 MPa. The impact resistances of the Al2O3/Al hybrid structure were further studied. The highest impact strength of the Al2O3/Al hybrid structure was 290.74 MPa. With the increase in cell size, the impact resistance of the Al2O3/Al hybrid structure had a gradual improvement trend. Under the cyclic impact, the Al2O3/Al hybrid structure showed a high impact strength and energy absorption capacity, which was mainly related to the metal phase content around the cell, i.e., the coherence of the metal phase. This study is believed to give help for the structural design of ceramic scaffolds and ceramic-metal hybrid structures.

Influence of Bamboo Fibers Weight Fraction on the Quasi-Static and Dynamic Compressive Responses of Epoxy Matrix Composites

ABSTRACT The influences of natural bamboo fibers (BFs) weight fraction on the microstructure, quasi-static and dynamic compressive responses of the epoxy resin matrix composites were investigated with the aid of scanning electron microscope, electronic universal testing machine and the modified Split Hopkinson pressure bar (SHPB) setup. The quasi-static compressive properties of the BFs/epoxy resin matrix composites suggested that the compressive strength were strongly improved with the addition of the natural BFs, which was attributed to the excellent strengthening effect. When the BFs content increased up to 15 wt.%, the compression ratio of the BFs/epoxy resin matrix composites showed 11% reduction than that of the unmodified epoxy resin. Moreover, the stress and strain were linear at the initial part but nonlinear when stress exceeds a certain value. SHPB impact tests results indicated that, compared with the pristine epoxy resin, the natural BFs reinforced epoxy matrix composite with 15 wt.% BFs exhibited the highest dynamic compressive strength, compression modulus and the best strengthening effect. Epoxy resin matrix composites also showed an obvious effect rate effective under impact load. Similar to that in the quasi-static compressive test, the addition of natural BFs has a positive effect in improving the compressive strength of the epoxy matrix.

Strain hardening rate and strain rate sensitivity behavior of bcc/fcc-dual-phase tungsten heavy alloy

90W-7Ni-3Fe alloy is a heterogeneous biphasic alloy, and it is essential to investigate the impact of the biphasic microstructure on key mechanical properties at varying strain rates. To address this issue, the quasi-static and dynamic compressive mechanical properties of dual-phase 90W-7Ni-3Fe alloy, single-phase pure W, and single-phase NiFe alloy were comparatively analyzed in conjunction with characterization analysis. The results indicate that the flow stress, strain hardening rate (SHR), and strain rate sensitivity (SRS) of the 90W-7Ni-3Fe alloy at various strain rates are mainly due to the involvement of W particles during the initial strain, although the overall plastic deformation of the alloy is attributed to the continuous coordinated deformation of the W particles with γ-(Ni, Fe) phases in various regions. In addition, the compressed W phase shows a typical 〈111〉 and 〈100〉 BCC compression texture and the compressed γ-(Ni, Fe) phase shows a typical 〈110〉 FCC compression texture, both with high Schmidt factors. These characteristics are essential for slip transfer and strain transfer from the γ-(Ni, Fe) phase to the W phase. Notably, the increased number of slip systems at high strain rates makes them more susceptible to both types of transfer, resulting in higher flow stress, SHR, and SRS during initial deformation.

Control of the Deformation Mode of Aluminum Foam-Filled Tubes as a Function of Foam Porosity

This paper focuses on the computational modeling of the crashworthiness performance of designed foam-filled thin-walled tubular structures under quasi-static compression loading. The studied foam sample is designed in SolidWorks using the ‘sphere subtraction method’ and implemented as a filler material in the thin-walled tube. The quasi-static compression was simulated by Abaqus software. The foam porosity is manipulated to enhance the crashworthiness performance of empty tubes. The deformation mode and energy absorption capability of the analyzed structures are introduced in detail. The numerical results showed that foam-filler material could change the deformation mode and improve stability during the compression process of thin-walled tubular structures. The number of lobes significantly increases when introducing the foam filler to the tube. These folds are affected by the foam porosity. Results also indicate that the total crushing load of the foam-filled tube is also a function of foam porosity, the mechanical response of the foam-filled tubes tended towards the response of the empty tube for a high porosity (P >85%), while for low porosity (P<85%) the mechanical response of the foam-filled tubes exhibits the three universal deformation characteristics of foams, namely, initial linear stage, extended plateau stage, and final densification stage. The main mechanical properties: collapse stress, plateau stress, and densification strain were obtained via the energy-efficient method for different configurations. The calculated mechanical properties exhibited a strong dependence on foam porosity. To give a quantitative description of the obtained quasi-static compressive properties, these properties are expressed as a function of foam porosity. The proposed formulas can easily recover the quasi-static compressive properties of the empty tube in the case of the absence of foam. The control of the compressive performance of foam-filled tubes as a function of porosity allows for finding an optimum geometry with a predefined foam porosity value adjusted for a given application.

A high-entropy alloy syntactic foam with exceptional cryogenic and dynamic properties

Metal foams are in great demand in extreme service environments with cryogenic temperatures and high strain rates due to their unique properties. However, the reduced ductility and impact toughness under such conditions limit their applications. In this work, we tested the quasi-static and dynamic compression properties of CoCrFeMnNi high entropy alloy syntactic foam at liquid nitrogen temperature (−196 °C). We found that it exhibits ultra-high strengths and energy absorption capacity, especially a superior resistance to embrittlement at cryogenic temperature. Microstructural characterizations reveal that the foam matrix has a high twinning activity and shear localization propensity in cryogenic environments. Dense deformation twins and multiple shear bands intersected, forming a weave-like microstructure that can disperse the deformation and benefits energy absorption. Deformation twins can also strengthen the matrix and delay the crack nucleation and growth. While under dynamic loading, an FCC to HCP phase transformation was activated, forming a nano-laminated dual-phase (NLDP) FCC/HCP structure in the matrix, leading to further strengthening and toughening. Deformation twinning and HCP phase transformation act as additional plastic deformation mechanisms along with stacking faults and shear bands to offset the shortcomings caused by limited dislocation movements at low temperatures and high strain rate dynamic loading, enabling the high strength and energy absorption of the syntactic foam.

Preparation, quasi-static, and dynamic compressive mechanical properties of BMG-W energetic structural materials

In this paper, the Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous alloy powder and the spherical W particles were used to prepare the BMG-xW (BMG=Bulk Metallic Glass, x = 10, 20, 30, 40, 50 vol%) energetic structural materials (ESMs) by spark plasma sintering. The research results on energy performance indicated that the Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy powder had excellent thermal reactivity, high combustion enthalpy and combustion integrity. The microstructure, quasi-static, and dynamic compressive mechanical properties of the BMG-xW ESMs were investigated. The quasi-static compression test showed that when the sintering temperature was 365 °C and above, the BMG-xW ESMs with the W content of 20 vol% to 50 vol% had similar fracture strengths and higher plastic deformation abilities than the BMG samples prepared under the same conditions. We have analyzed the plasticity enhancement mechanism of the BMG-xW ESMs. In addition, the failure modes of the BMG-xW ESMs were all shear fracture, which was conducive to exerting their shear self-sharpening. The Hopkinson compression bar test showed that the fracture strength and failure strain of the BMG-xW ESMs were greater than the Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG under dynamic compression at the same strain rate, and the higher the W content, the fracture strength and failure strain tended to increase. All samples showed obvious flame during dynamic compression. The larger the strain rate, the lower the W content, the shorter the ignition delay time, the faster the flame spreading speed and the longer the combustion time. The damage experiment confirmed that the BMG-xW ESMs had significantly superior damage performance than the Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG.

Fiber architecture effect on tensile and compressive damage mechanisms of 3D angle-interlock woven composites

Due to the intricate fiber architecture of 3D textile composites, understanding their failure mechanisms presents a challenge. Here we experimentally studied the quasi-static tensile and compressive properties of 3D angle-interlock woven composites (3D AWC) under both warp-loading (AWC-warp) and weft-loading (AWC-weft). Damage morphologies and mechanisms were examined using optical microscopy and X-ray computed tomography. In order to demonstrate the effect of fiber architecture, the results were combined and compared with that of unidirectional (UD) composites with the same total fiber volume fraction (FVF). The fiber architecture effects in 3D AWC can be manifested as the on-axis FVF dependency and fiber undulation influence. When on-axis load-bearing fiber is undulating-free, the difference in mechanical properties is primarily determined by the on-axis FVF. However, the presence of fiber undulation can further weaken the mechanical properties. Moreover, for AWC-warp specimens, fiber undulation has a significant impact on the modes and characteristics of damage, resulting in fiber breakages and kinks that primarily occur in the connection region of warp yarns.

Acoustic Emission Characterization Analysis of Quasi-Static and Fatigue Compression Properties of Aluminum Foam

In order to explore the evolution of physical and mechanical properties and acoustic emission (AE) characteristics of aluminum foam under fatigue and quasi-static compression from a microscopic point of view, the AE monitoring technology was used to analyze the deformation, hardening, and energy absorption characteristics of open-cell aluminum foam under quasi-static compression at different rates (2, 10 and 50 mm/min) and fatigue loading tests with different peak stress ratios k (k = maximum stress/yield stress) by means of MTS fatigue testing machine and CCD camera. The results indicated that under different compression rates, the AE ring down count had the same trend as the engineering stress–strain response of the specimens, the AE ring down count rate at the plastic deformation stage showed the same performance as the work hardening rate, and the AE energy absorption efficiency corresponded well to the experimental results. The specimen entered the densification stage with the stability of AE count and the decrease in energy absorption efficiency. During the fatigue tests of different k values, the change trend of strain was consistent with the response of acoustic emission characteristic parameters, and the fatigue compression damage caused by the deformation process of the specimen can be monitored by the change in AE characteristics. The AE characteristics can dynamically monitor the compression process and provide a new research method and idea for the study of mechanical properties of aluminum foam.

Quasistatic Compression Properties of Fiber Hybrid Ceramic Matrix Composites with Different Hybrid Ratios and Fiber Dispersions

Fiber hybrid composites can give full play to the performance advantages of different component fibers, and hybrid weaving is one of the effective methods to improve the properties of composite materials. Herein, based on the flexible‐oriented 3D woven technology, fiber hybrid ceramic matrix composites (FHCMCs) with different hybrid ratios and fiber dispersions are designed and fabricated, and their quasistatic compression properties, failure modes, and hybrid effects are studied. The results show that the reasonable hybrid of carbon (C) fiber and silicon carbide (SiC) fiber can make up for the shortcoming of single‐fiber composites and improve the compression properties of FH‐CMCs. The compressive failure modes of the FH‐CMCs are mainly the crushing failure in the C fiber layers and shear failure of the specimen. For the compressive failure deformation, the positive hybrid effect gradually becomes obvious with the increase of fiber dispersion, but the compressive strength shows a negative hybrid effect as a whole. The improved rule of mixture by introducing different parameters has a better prediction effect for the compressive strength of the FH‐CMCs. The research results provide experimental and theoretical reference for the high‐performance manufacturing of hybrid composites in the future.

Effect of Strain Rate on Compressive Properties of Aluminium-Graphene Composites

Graphene-reinforced aluminium composites have been widely studied due to their excellent mechanical properties. However, only a few studies have reported their dynamic compression properties. The purpose of this study is to investigate the quasi-static and dynamic compression properties of graphene-reinforced aluminium composites. The addition of graphene improved the compressive stress resistance and energy absorption capacity of the aluminium matrix. An aluminium-0.5 wt.% graphene composite exhibited good compressive properties due to the different interfacial wave impedance generated by the additional grain boundaries or Aluminium-Graphene interfaces.

Transverse indentation response and residual axial compressive characteristics of metal-composites hybrid tubes by deep learning-based acoustic emission and micro-CT

This work investigated transverse indentation response and residual axial compressive characteristics of Al-CFRP hybrid tubes with different configurations. The failure mechanism and damage evolution of the hybrid tubes under transverse indentation load were investigated by acoustic emission and micro-CT technologies. To gain an insight into the damage mechanism of CFRP composites, a structural health monitoring system based on image-based acoustic emission waveform and deep learning was developed. It showed that acoustic emission response of internal damage was corresponding to the damage visualization analyses of micro-CT. The proposed damage classification model provided a reliable path for extreme damage mode recognition and damage monitoring of composite structure. Under transverse indentation load, delamination and fiber breakage were the main failure modes of H-I hybrid tube (i.e. the CFRP tube internally filled with aluminum tube). For H-II hybrid tube (i.e. the aluminum tube internally filled with CFRP tube), the interfacial delamination of Al/CFRP tended to aggravate its failure behavior. The quasi-static axial compressive properties of intact and pre-indentation tubes were further compared to evaluate the effects of indentation damage on residual crashworthiness. The transverse indentation resulted in the change of the failure mode. Compared with H-I hybrid tube, H-II hybrid tube showed more significant property degradation.

Enhancement in Mechanical Properties of Glass/Epoxy Composites by a Hybrid Combination of Multi-Walled Carbon Nanotubes and Graphene Nanoparticles

In this work, an attempt was made to improve the mechanical performance of glass fibre-reinforced polymer composites by adding multi-walled carbon nanotubes (MWCNT) and graphene nanoparticles (GNP) and their hybrid combination at different weight fractions (0.1 to 0.3%). Composite laminates with three different configurations (unidirectional [0°]12, cross-ply [0°/90°]3s, and angle-ply [±45°]3s) were manufactured using the compression moulding method. Characterisation tests such as quasistatic compression, flexural, and interlaminar shear strength properties were carried out per ASTM standards. Failure analysis was carried out through optical and scanning electron microscopy (SEM). The experimental results showed a substantial enhancement with the 0.2% hybrid combination of MWCNTs, and GNPs showed 80% and 74% in the compressive strength and compressive modulus, respectively. Similarly, flexural strength, modulus, and interlaminar shear strength (ILSS) increased by 62%, 205%, and 298%, respectively, compared to neat glass/epoxy resin composite. Beyond the 0.2% of fillers, the properties started to degrade due to the agglomeration of MWCNTs/GNPs. The order of layups per mechanical performance was UD, followed by CP and AP.