Quasi-static Compressive Behavior Research Articles

Experimental investigation on axial quasi-static compression and low-velocity impact behaviors of perforated thermoplastic composite cylindrical shells

Perforation in cylindrical shells is commonly a typical technique to fulfill relevant functional requirements. However, how the perforation influence the mechanical performance of thermoplastic composite cylindrical shells (TPCCS) is incompletely understood. Hence, a systematic investigation through quasi-static compression and low-velocity impact (LVI) experiments was carried out in this paper. The full-field strain distributions of TPCCS intact tubes (IT) and perforated tubes (PT) were monitored by using 3D-DIC, and the residual properties were also characterized by compression-after-impact (CAI) tests. The results show that under quasi-static compression, the structural stiffness decreases significantly with increasing perforation diameter. The perforation reduces the interference of internal random defects on the structural deformation mode, which leads to a significant strain concentration in PT. The peak force and initial stiffness under LVI are smaller than those under quasi-static compression, with IT displaying higher sensitivity to dynamic loading compared to PT. At the impact energy of 100 J, IT and PT exhibit “S”- and “X”-shaped deformation modes, respectively. CAI tests indicate that although PT has a poorer residual load-carrying capacity than IT, it retains good structural integrity and secondary energy absorption capacity. This study provides a valuable reference for the assessment and application of perforated TPCCS.

Study of quasi-static tensile and compressive behaviors of laminated bamboo under service temperature

Laminated bamboo presents significant potential for applications in the construction industry. The stress-strain relationship and failure mechanism of laminated bamboo across the service temperature range, spanning from low to high temperatures, remain incompletely elucidated. Addressing this research gap, this paper conducts experiments on tension and compression of laminated bamboo in both parallel to grain direction and perpendicular to grain direction across an extensive temperature range of −40 to 80 °C. Temperature reduction factors according to Eurocode 5 are established, followed by adjustments based on RO constitutive model. Subsequently, a two-section constitutive model for laminated bamboo materials under service temperature is developed. This model is designed to accurately describe the stress-strain relationship of laminated bamboo in various temperature environments. The constitutive model proposed in this paper adeptly predicts the strain hardening behavior of laminated bamboo during compression, demonstrating high accuracy post-yield stress and addressing the non-convergence issue prevalent in most existing models. Additionally, the influence of temperature on fracture mechanism was explored using Scanning Electron Microscopy (SEM). The study delves deeply into the fundamental reasons behind temperature's effect on the mechanical properties of laminated bamboo, examining it from a chemical composition standpoint. This study not only offers significant insights for the application of laminated bamboo in construction projects but also serves as a valuable resource for advancing the understanding of laminated bamboo's mechanical behavior under various temperature conditions. The findings are crucial for architects, engineers, and material scientists, guiding them in optimizing the use of laminated bamboo in sustainable building practices and enhancing the structural integrity of bamboo-based construction.

Quasi-static compressive fracture behavior of three-period minimum surface Al2O3 / Al composites fabricated by stereolithography

Extensive research has been conducted on the structures and preparation methods of ceramic/metal composites to achieve materials with superior strength and toughness. Among these, the triply periodic minimal surface (TPMS) structure stands out due to its remarkable advantages. In this study, we employed SLA additive manufacturing to fabricate a Gyroid-structured ceramic skeleton, and utilized metal infiltration to prepare interpenetrating Al2O3/Al composites. A comparison was made between the compressive properties of Al2O3/Al interpenetrating composites with Gyroid curved surface structure and those with honeycomb structure. The experimental outcomes indicate that compressive failure in both structural composites primarily occurs at the bond interface between the ceramic framework and the metal. These composites exhibit brittle fracture and experience shear failure. Furthermore, the compressive failure mechanism involves a mixed fracture composed of cleavage and micropore polymerization fractures. Gyroid curved structural composites exhibit lower local stress concentration due to their smooth and regular topology, rendering them with higher strength and ductility compared to honeycomb structural composites. The ultimate compressive strength of the Gyroid curved composite is 264 MPa, representing a 3.8-fold increase over the honeycomb structure.

Experimental and simulation study on effects of material and loading direction on the quasi-static compression behavior of re-entrant honeycomb structure

The re-entrant honeycomb structure has a strong energy absorption capacity because of its auxetic characteristics. The energy absorption capacity of the re-entrant honeycomb structure is closely related to the material and loading direction. In this paper, the Selective Laser Sintering(SLS) 3D printing technology was used to print the re-entrant honeycomb structure with commonly used FS3300PA and Glass Fiber reinforced FS3300PA. A quasi-static compression finite element model was developed for the re-entrant honeycomb structure printed with two materials when loaded along three directions. The influence of material and loading direction on the quasi-static compression performance of re-entrant honeycomb structures was systematically studied through simulation and experiments. The deformation mode and energy absorption index of the simulation results are in good agreement with the experimental results, verifying the effectiveness of the finite element model. The results show that the deformation mode and energy absorption performance of the structure are affected by the material and loading direction. The quasi-static compression performance in the Y direction is optimal for both materials. However, when loading along the Y direction, the specific energy absorption of FS3300PA printed re-entrant honeycomb structure is 18.3 % higher than that of FS3300PA + 30 % Glass Fiber printed re-entrant honeycomb structure, ηCFEis 83.3 % higher. Therefore, when the re-entrant honeycomb structure of the two materials is loaded in different directions, the structure printed with FS3300PA has the best quasi-static compression performance when loaded in the Y direction.

Low-cycle compression-compression fatigue behavior of MEX-printed PLA parts

Due to cyclic loads, additively manufactured (AM) parts can collapse at lower stress values than the strength corresponding to static loads. To date, there is limited research on the fatigue life of AM polymers. The present work investigates the fatigue behavior of material extrusion (MEX) printed Polylactic acid (PLA) parts. In this regard, the low-cycle fatigue (LCF) domain was studied and a compression-compression fatigue test setup was adopted. Initially, before the experimental tests, the MEX-printed samples were subjected to physical assessments. The printed fatigue samples presented a high accuracy with dimensional relative errors below 0.04%, while 6.66% was noted as their mass relative error. Subsequently, quasi-static and cyclic tests were performed in order to determine the mechanical behavior of the AM parts, with special focus on the low-cycle domain of the S-N (or Wöhler) curve. The quasi-static compression behavior of the PLA samples is typical of cellular materials, the samples highlighting a shear band as a failure mechanism. Five load levels were used to plot the low-cycle domain of the S-N (or Wöhler) curve with its 95% level confidence bands. The tests were performed in force-controlled mode with the stress asymmetry ratio R = 0.1 and at the test frequency of f = 10 Hz. An exponential relationship was also found between the strain at break and the number of cycles until failure. The failure of the samples in fatigue load occurred suddenly.

Strengthening nodes to obtain high-strength pyramid lattice structure by using wire arc additive manufacturing method

Compared with traditional manufacturing methods, the wire arc additive manufacturing (WAAM) method has significant advantages in manufacturing pyramid lattice structures. In this study, two types of pyramid lattice structures were manufactured using WAAM, with a focus on their quasi-static compression behavior and microstructure at node positions. Simultaneously, the finite element method was used to compare with the actual experimental results. A theoretical analysis was conducted on the reasons why the node position affects the overall strength of the pyramid lattice in WAAM. Research has shown that the compressive performance of WAAM pyramid lattice structures is mainly determined by the node position. Strengthening the node position can improve the overall compression performance of the structure. The method of strengthening node manufacturing proposed in this article can increase the overall strength by 14.3 %. The research results provide concise and effective guidance for enhancing the strength of pyramid lattice. This conclusion is of great significance for further exploring the mechanical properties of pyramid lattice structures produced using WAAM.

Effect of free water on the quasi-static compression behavior of partially-saturated concrete with a fully coupled DEM/CFD approach

Effect of free water on the quasi-static compression behavior of partially-saturated concrete with a fully coupled DEM/CFD approach

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.

Quasi-static and dynamic compressive behaviour of additively manufactured Menger fractal cube structures

This paper presents the first-ever investigation of Menger fractal cubes' quasi-static compression and impact behaviour. Menger cubes with different void ratios were 3D printed using polylactic acid (PLA) with dimensions of 40 mm × 40 mm × 40 mm. Three different orders of Menger cubes with different void ratios were considered, namely M1 with a void ratio of 0.26, M2 with a void ratio of 0.45, and M3 with a void ratio of 0.60. Quasi-static Compression tests were conducted using a universal testing machine, while the drop hammer was used to observe the behaviour under impact loading. The fracture mechanism, energy efficiency and force-time histories were studied. With the structured nature of the void formation and predictability of the failure modes, the Menger geometry showed some promise compared to other alternatives, such as foams and honeycombs. With the increasing void ratio, the Menger geometries show force-displacement behaviour similar to hyper-elastic materials such as rubber and polymers. The third-order Menger cubes showed the highest energy absorption efficiency compared to the other two geometries in this study. The findings of the present work reveal the possibility of using additively manufactured Menger geometries as an energy-efficient system capable of reducing the transmitting force in applications such as crash barriers.

Investigation into quasi-static compressive behaviors of several kinds of honeycomb like structures in three axial directions

The natural beesʼ honeycombs maintain long-term structural stability in harsh environments, employing a highly material-efficient approach. However, the reasons remain somewhat ambiguous. To clarify the stabilization mechanism and investigate quasi-static compression responses of double-layer ordered cellular structures, honeycomb, Tóth and single-layer cellular structures with a relative density (ρr) of 25.84 % were fabricated using 3D printing technology. Then, quasi-static compression experiments in three directions were conducted. Further, a numerical study was conducted to uncover the stabilization mechanism and effect of ρr on compressive behaviors. Results revealed that the stabilization mechanism was mainly attributed to bearing load priority of intermediate layer and its inhibition on formation of plastic hinges. A relative density of 5.17 % served as a transition point for deformation mode, beyond which honeycomb and Tóth structures exhibited stronger in-plane compressive strength at expense of less sacrificed out-of-plane compressive strength, below which they both exhibited more stable compressive curves compared to single-layer cellular structures, which were favorable for energy absorption. This study clarifies the stability mechanism of beesʼ honeycombs and addresses the lack on compression behaviors of double-layer ordered cellular structures. Moreover, it introduces two available bionic structures with controllable deformation modes to expand the application of single-layer cellular structures.

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.

Numerical investigation of the influence of mineral mesostructure on quasi-static compressive behaviors of granite using a breakable grain-based model

The mesostructure of brittle rocks, such as granite, plays a vital role in determining their mechanical properties and failure mode. Understanding the influence of rock mesostructure on mechanical behavior requires a realistic representation of grain size distribution, grain shape, and average grain size. In this study, we developed a breakable polygonal discrete element model that incorporates mineralogical composition, grain size distributions, and grain shape to simulate the rock mesostructure. Numerical specimens with varying mesostructures were created to represent different grain size, shape, and distribution characteristics. Quasi-static uniaxial compressive loading tests were conducted on these specimens to analyze their peak strength and macroscopic failure modes. The results revealed a strong linear relationship between the quasi-static compressive strength of the rock and mesostructure parameters, including average grain size, grain size coefficient, and grain roundness. Additionally, the simulation results demonstrated that the rock mesostructure significantly influenced the quasi-static compression failure mode. The proposed breakable polygonal discrete element model has the potential to predict the macroscopic behavior of brittle rocks accurately. It provides a reliable method for studying the effect of mesostructure on the quasi-static compressive mechanical behavior of rocks.

Mechanical response of functionally graded lattices with different density grading strategies

This paper explains the quasi-static compressive behaviour of functionally graded lattices made of polyamide PA11 by multi jet fusion (MJF). The effects of various unit cell topologies such as body-centred cubic (BCC), rhombic dodecahedron (RD), and octet (OT) unit cells, as well as different stacking configurations were examined to achieve bi-directional and uni-directional grading in the lattice structures. Moreover, the strut diameters of the lattices were changed to obtain different relative density grading. The experimental results showed that topology grading played a dominant role in tuning the deformation patterns, stress-strain curves, and the energy absorption capacity of the lattice structures. Based on the numerically simulated results obtained from the validated finite element models, a semi-empirical formula was subsequently developed to predict the plateau stress of the studied FG lattices. Further numerical studies on the effects of the loading direction and the cell arrangement showed that the specific plateau stress and specific energy absorption capacity of the lattices compressed along the loading direction (z) were higher than those when they were compressed in the lateral (x) direction. Additionally, the cell arrangement predominately affected the deformation patterns and stress-strain curves. The findings of this study revealed that desired crushing performance of lattice structures can be achieved through functional grading of cell topologies, and it can be further enhanced by incorporating strut diameter grading.

Quasi-static and dynamic compressive behavior of Zr-based bulk metallic glass with yttrium addition

The glass-forming ability, stress-strain relationships, and fracture characteristics of Zr60-xCu27Al8Fe5Yx (x =1, 3 and 5 at%) bulk metallic glasses are investigated under compressive strain rates ranging from 10−3 to 4 × 103 s−1 using a material testing system and split-Hopkinson pressure bar. The results show that yttrium addition leads to a broader supercooled liquid region (ΔTx) and a greater γ parameter (γ = Tx/(Tg+Tl)), particularly for x = 1 at%. For all of the tested alloys, the fracture stress increases with increasing strain rate, while the fracture strain decreases. The addition of 3 at% Y results in the highest fracture stress and an improved fracture strain. The fracture surface observations show that the fracture behavior of the BMGs is dominated by the strain rate, whereas the Y content plays only a minor role.

Effect of strain rate and high temperature on quasi-static and dynamic compressive behavior of forged GH5188 superalloy

GH5188 Co-based superalloy is commonly employed in aero-engine eddy current and high-temperature components. Nonetheless, current research on its response behavior and mechanisms under dynamic and temperature loading remains scarce. Therefore, this study aims to investigate the dynamic compression and related deformation mechanism of GH5188 superalloy under the coupling effect of high temperature and strain rate. Quasi-static and dynamic compression tests were conducted on the forged GH5188 superalloy at both room temperature and 1000 °C. The results indicate that the material displays impressive yield strength and plasticity, while also showing a pronounced temperature sensitivity and strain rate hardening effect. Additionally, the dynamic stress-strain constitutive relationship of GH5188 is described by the modified J-C model. Regarding the dynamic deformation mechanism, GH5188 exhibited microbands, stacking faults, and nanotwins during high-strain rate compression. At 1000 °C, GH5188 underwent discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) at strain rates of 6000 s−1 and 10000 s−1, respectively. The synergistic effect of microbands and twinning enhanced the dynamic deformation ability and strengthening effect of the material. The transformation of microshear bands generated nanotwins. The twin boundaries are high-energy zones that can provide suitable recrystallization nucleation sites, induce dynamic recrystallization process, and thus obtain a fine and uniform equiaxed grain structure.

Experimental investigation of the quasi-static and dynamic compressive behavior of polymer-based 3D-printed lattice structures

Because additive manufacturing (AM) allows the creation of complex structures that can be tailored or optimized based on mechanical and material specifications, it is increasingly used for various applications. Among others, it gives access to new designs of lightweight shields exhibiting good capabilities for absorbing dynamic loads and kinetic energy. In the present work, the quasi-static and dynamic compressive behavior of 3D polymeric lattice structures manufactured by the fused deposition modeling (FDM) process were evaluated. Two different materials were considered: ABS (Acrylonitrile Butadiene Styrene) and Tough-PLA (PolyLactic Acid). First, the tensile quasi-static mechanical properties of precursor filaments and 3D-printed dog-bone specimens were evaluated. Through these tests, it was observed that the printing process and orientation have a significant effect on the mechanical behavior of AM-produced samples. Then, quasi-static and dynamic compressive tests were conducted on AM-produced cylindrical specimens using two distinct printing topologies. The dynamic tests were performed with a split Hopkinson pressure bar (SHPB) apparatus. The results indicated that the compressive strength increases with the loading rate, indicating a strain rate sensitivity of the studied materials. Finally, three different 3D lattice structures were experimentally evaluated against crushing at two different deformation rates. It was noted that the geometrical design and relative densities of these structures have major effects on their energy absorption capability. However, no clear correlation seems to exist between energy absorption capabilities under quasi-static and dynamic loading conditions.

The compressive responses and failure behaviors of composite graded auxetic re-entrant honeycomb structure

This paper investigated the quasi-static compressive performances and failure behaviors of composite auxetic re-entrant honeycomb sandwich structure. Three types of auxetic re-entrant honeycomb structures with different gradient configurations were manufactured and tested. The carbon/epoxy prepreg was used to fabricated the auxetic re-entrant honeycomb sandwich structure. The reaction force and displacement of the test fixture were collected by the transducer of the universal testing machine. The compressive processes of specimens were recorded by high-resolution camera. Combined with the stress–strain curves and deformation processes of composite structures, the compressive responses and deformation mechanisms was analyzed. The Poisson’s ratio, energy efficiency and plateau stress of re-entrant honeycomb sandwich structures were defined and utilized to study the auxetic performance and energy absorption ability. Furthermore, a high-fidelity numerical model was established and finite element software ABAQUS was used to analyzed the compressive performances and failure behaviors of composite graded auxetic re-entrant honeycomb structure. The compressive failure modes of the numerical simulation results were compared with that of the experimental results, and the numerical simulation results agreed well with the experimental results. The results indicated that average structure exhibited best energy absorption performance and bidirectionally graded auxetic honeycomb structure had the best negative Poisson’s ratio performance.

Quasi-static and dynamic compression of additively manufactured functionally graded lattices: Experiments and simulations

In this paper, quasi-static and dynamic compressive behaviors of functionally graded (FG) lattices made of stainless steel (SS 316L) by electron beam melting (EBM) were experimentally investigated. The FG lattice structures were body-centered cubic (BCC) lattices with uni-directional density grading and bi-directional density grading. Their performance was compared with that of uniform lattices of the same relative density. The experimental results showed that, as compared with the uniform and uni-directional density graded lattices, the novel bi-directional density graded lattices witnessed the highest plateau stress and energy absorption capacity at the considered loading conditions. The deformation pattern and the stress distribution of the structures during the crush were further studied using finite element modelling (FEM). The finite element modelling showed that the enhanced strength and energy absorption were related to the periodic collapse of graded structures corresponding to the density gradient strategy. Two parametric studies were conducted using the experimentally validated FEM models to examine the influence of density gradient on the dynamic response of FG lattices.

Theoretical, numerical, and experimental study on quasi-static compressive behaviors of elliptical anti-chiral auxetic structure

Theoretical, numerical, and experimental study on quasi-static compressive behaviors of elliptical anti-chiral auxetic structure

Effect of temperature and strain rate on quasi-static and dynamic compressive behavior of forged CrMnFeCoNi high entropy alloy

The equiatomic CrMnFeCoNi high entropy alloy (HEA) has attracted much attention due to the superior ductility. However, as a face-centered cubic (FCC) single-phase solid solution, the as-cast CrMnFeCoNi HEA is limited in many applications because of the low strength. The aim of this work is to improve the mechanical properties of CrMnFeCoNi HEA by forging. The forged CrMnFeCoNi HEA was prepared and the effect of temperature and strain rate on the deformation behavior and mechanism under quasi-static and dynamic compression was investigated. After hot forging, CrMnFeCoNi HEA still maintained FCC single-phase structure, the average grain size reduced to ∼40 μm, the distribution of elements was more uniform, and some defects were introduced into the material. The quasi-static (1 × 10−3 s−1) and dynamic (2 × 103, 7 × 103 and 1 × 104 s−1) compression tests of forged CrMnFeCoNi HEA were performed at temperatures ranging from −196 °C to 950 °C. The material exhibited excellent compressive strength and great plasticity, and showed significant temperature sensitivity and strain rate sensitivity of the yield strength. When the strain rate was up to 1 × 104 s−1, the yield strength was ∼1076 MPa at −100 °C and ∼80% higher than that under quasi-static compression. The strain hardening rate increased with the decrease of temperature under both quasi-static and dynamic conditions, while strain rate sensitivity was exhibited only at high temperatures. Discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX) and twinning-induced dynamic recrystallization (TDRX) were activated during hot compressions. DDRX was activated when the strain rate was low, and CDRX and TDRX were strengthened with the increase of strain rate. The influence of strain rate and temperature on the deformation mechanism was investigated. Low temperature and high strain rate were conducive to the formation of deformed twins.