Energy Absorption Values Research Articles

Experimental investigation on the mechanical properties of Ti6Al4V cellular structures produced with selective laser melting: Effects of rib thickness, unit cell type and orientation

The objective of this study is to investigate the mechanical performance of Ti6Al4V cellular structures, including different unit cell forms such as honeycomb, re-entrant, hybrid (honeycomb + re-entrant), and chiral structures manufactured with selective laser melting. The study examines the influence of rib thickness and unit cell orientation on compressive strength, elasticity modulus, Poisson's ratio, energy absorption, and specific energy absorption. Increasing the rib thickness of the unit cells improved not only the compressive strength and elasticity modulus of the samples but also their energy absorption capacities. The mechanical properties of the cellular structures varied with changes in unit cell orientation, and no direct relationship was found. The highest values for compressive strength, energy absorption, and specific energy absorption were observed in re-entrant structures, while hybrid structures had the highest elasticity modulus values. It was also found that chiral structures had the lowest compressive strength, modulus of elasticity and energy absorption capacity of all the parameters investigated. In addition, re-entrant structures with negative Poisson's ratio tend to perform positive Poisson’s ratio when they are subjected to deformation under compression. The elasticity modulus of the biocompatible Ti6Al4V cellular structures is similar to that of femoral bone values. These structures meet the requirements for use in the core of implants. The results obtained from this experimental study may guide researchers in the field of biomechanics.

Enhanced Crashworthiness Parameters of Nested Thin-Walled Carbon Fiber-Reinforced Polymer and Al Structures: Effect of Using Expanded Polypropylene Foam

The in-plane loading conditions of carbon fiber/epoxy composite (CFRP) and aluminum nested-tube-reinforced expanded polypropylene (EPP) blocks were empirically examined. This study used crashworthiness metrics to estimate the best design configuration under quasi-static loading rates. The experimental phase began with lateral loading testing of single and nested aluminum and CFRP specimen. In-plane crushing experiments were performed on EPP foam blocks reinforced with nested tubes. Both single and nested aluminum tubes had comparable force–response curves and maintained their load-bearing capacity throughout testing. Despite a load-carrying capacity drop above a particular displacement threshold, the CFRP specimens had superior specific energy absorption (SEA) values due to their lightweight nature. The triple-tube nested specimens with two smaller tubes exhibited the best SEA results (1.72 and 1.88 J/g, respectively, for the aluminum and CFRP nested samples). During concurrent tube deformation, the nested samples showed a synergistic connection that increased energy absorption, especially in the EPP foam blocks with reinforced tubes. The study also examined the effects of building nested specimens with aluminum exterior tubes and CFRP inner tubes, and vice versa. This method showed that CFRP tubes within aluminum outer tubes lowered specimen weight (from 93.1 g to 67.7 g) and energy absorption (from 160.2 J to 153.3 J). However, the weight reduction outweighed the energy absorption, increasing SEA values for certain composite material configurations (from 1.72 J/g to 2.26 J/g).

Out-of-plane compressive properties of a butterfly-shaped auxetic metamaterial

Abstract Inspired by butterfly, a bio butterfly-shaped auxetic metamaterial (BSAM) was recently proposed in which the unite cell of BSAM was designed based on silhouette of a butterfly. The distinguished in-plane mechanical properties made the BSAM a potential absorber to be used in a broad range of applications. The aim of this study is to examine the out-of-plane mechanical properties under quasi-static compression. Using the validated FE models, a comparison was carried out between BSAM and two popular auxetic honeycombs, namely, re-entrant (RE) and modified re-entrant (MRE). Results showed that the nominal stress-strain curves of the BSAM were significantly higher than those of auxetic honeycombs (RE and MRE). However, the MRE revealed the highest Young’s modulus. The plateau stresses were 10.5 MPa, 7.5 MPa and 3.3 MPa for the compressed BSAM, MRE and RE, respectively. Furthermore, the calculated values of the specific energy absorption per volume (Wv) of the three structures indicated that the percentage of the absorbed energy by the BSAM was 182% and 456% higher than those absorbed by the MRE and RE, respectively. Based on the determined values of ideal Wv (11.4 J/cm3 “BSAM”, 5.2 J/cm3 “MRE” and 2.3 J/cm3 “RE”) , the energy efficiency of the three structures was 64%, 79% and 69% of the total energy in the case BSAM, MRE and RE, respectively. Moreover, the influence of the in-plane thickness (t1) and the thickness of cylinders (t2) on the mechanical performance of the BSAM were examined through a parametric study. Findings of the parametric study indicated that the mechanical properties as a function of t1 were considerably affected, while moderate influence was resulted as a function of t2.

Investigating the mechanical properties and crashworthiness of hybrid PLA/GFRP composites fabricated using FDM-filament winding

The failure and crashworthiness performance of hybrid Polylactide (PLA)/Glass Fiber Reinforced Polymer (GFRP) composite tubes subjected to axial and radial quasistatic compression loads were investigated in the present study. The composite tubes are fabricated using hand lay-up and Fused Deposition Modeling (FDM)-filament winding processes. The crashworthiness performance was studied using parameters such as the peak load, energy absorption, crush load, crushing load efficiency, and specific energy absorption. The highest peak loads from the compression test results in the axial and radial directions are calculated using variations in the filament winding PLA/GFRP (FPG) specimen, whose values were 16130.50 N and 12077.33 N, respectively. The highest mean crush load is found in the material variation with the FPG specimen, which is 5734.43 J/mm for axial loading and 4886.75 J/mm for radial loading. The highest energy absorption (EA) value is found in the material variation with the FPG specimen, which is 262.18 J for axial direction loading and 94.02 J for radial direction loading. The highest specific energy absorption (SEA) value is found in the material variation with the specimen Filament Winding PLA/GFRP, which is 16.92 J/g for axial loading and 10.98 J/g for radial loading. There are three main types of failure of the composite: matrix cracking, fiber damage, and folding. The study showed that by combining Additive Manufacturing and composite lamination, the hybrid PLA/GFRP specimen outperformed the existing structures.

The study on the wood candidates for the impact limiter of a spent fuel cask

The nuclear fuel transportation package is meticulously designed to enclose radioactive materials, guaranteeing containment even after undergoing a free-drop impact test and considering potential accident situations to prevent radioactive leakage. The impact limiters attached to the transport cask are engineered to absorb impact energy. Wood, renowned for its strong energy absorption capacity, is often specified as the core material within impact limiters. It is crucial to accurately determine the wood material employed in the impact limiter. This study carried out crushing experiments on various common wood materials to obtain stress versus strain data for the selection of the appropriate wood material. Indicators such as density, crushing strength, and densification strain are utilized to assess the suitability of wood as the filler material of the impact limiter. Paulownia wood is chosen based on density, the appropriate energy absorption value per unit volume, and response acceleration. The dispersity of the strengths of Paulownia wood is taken into account with the weakest-link models. The finite element method is adopted to precisely design and verify the impact limiter. The arrangement of the glulam wood is designed to balance the energy absorption in hypothetical accident conditions. Finally, tests on the application of the impact limiter in the transportation cask were conducted to validate the proper design of the impact limiter. This study can offer reference and data support for the research on wood filler materials.

Effect of geometric configurations and curvature angle of corrugated sandwich structures on impact behavior

AbstractThe aim of this study is to numerically investigate the low‐velocity impact behavior of carbon fiber reinforced orthogonal woven fabric composite sandwich structures with five different geometric configurations and four different curve angles. Low velocity impact simulations were performed in LS DYNA finite element program to investigate the effects of core configuration and curve angle on peak contact force, energy absorption efficiency and damage mode. A progressive damage analysis based on the combination of the Hashin damage criterion and the Cohesive Zone Model (CZM) with bilinear traction‐separation law was performed using the MAT‐54 (ENHANCED_COMPOSITE_DAMAGE) material model. Among the five different cores, Trapezoidal core has the highest peak force average of 2.9 kN while Triangular core sandwich structure has the lowest with 1.23 kN. Absorbed energy efficiency average was highest for rectangular core with 0.95 and lowest for sinusoidal core with 0.69. The specific absorbed energy value was highest for Triangular core with 0.312 J/g and lowest for Sinusoidal core with 0.178 J/g. The damage area on the structure increased with increasing curve angle. It was determined that the core structure and curve angle is an effective parameter on peak force and energy absorption efficiency.Highlights Impact behavior of sandwich composite structures was examined. The effects of core type and curve angles on peak force, energy absorption efficiency and specific absorption energy were investigated. Specific absorption energy rates were compared with studies in the literature.

Behavior of sandwich structures with 3D-printed auxetic and non-auxetic cores under low velocity impact: Experimental and computational analysis

In recent years, impact-resistant structures are highly sought after in various fields such automotive and aerospace applications as they proved notable performances, garnering significant success. The aim of this study is to assess the behavior of the 3D-printable honeycombs subjected to low velocity impact, for providing insights into absorbed energy for different core designs: hexagonal, auxetic, and rectangular, considering an equal number of cells across all designs. This work reports the computational and experimental studies conducted for sandwich structures under different impact loading. The experimental impact tests are carried out using a drop weight impact-testing machine. The examined specimen comprises two face-sheets and architected cell core fabricated through the Fused Filament Fabrication (FFF) process made of polylactic acid (PLA). Variations in the geometric design of the cells result in the formation of cores with auxetic and non-auxetic topologies. Uniaxial tensile tests are performed to identify the mechanical properties of the involved biopolymer. The second attempt consists on comparing three architectural core structures under impact test using experimental and computational methods. Our findings highlight the specific influence of core topology on energy absorption in 3D-printed sandwich structures. Results indicate that while all three configurations (hexagonal, re-entrant, and rectangular) demonstrate comparable energy absorption values, the specific mechanisms and efficiencies vary, with re-entrant cores exhibiting distinct behaviors under impact.

A comparative study of self pierceing riveting and mechanical clinch of DP590-Al5754 high-strength steel and aluminum alloys

This paper presents a comparative study of two joining processes, self piercing riveting (SPR) and mechanical clinch, used to join DP590 high-strength steel and Al5754 aluminum alloy. A comparative study of microhardness, tensile shear properties, fatigue properties, and economics of joints from both processes was conducted. The findings indicate that the highest hardness levels are observed in the rivet leg region for SPR joints and in the neck region for mechanical clinch joints. The maximum failure load and energy absorption values of SPR joints were found to be 1.46 and 9.07 times higher, respectively, than those of mechanical clinch joints. The static tensile test results demonstrate that the strength and hardness of SPR joints in aluminum sheets subjected to cold work hardening are significantly lower than those of steel sheets. Therefore, the failure of SPR joints is primarily attributed to the deformation and fracture of the lower aluminum sheet. Mechanical clinch joints fail by neck fracture because the steel sheet neck becomes brittle by cold work hardening and the neck thickness is small. The fatigue behavior of SPR joints was observed to be superior to that of mechanical clinch joints. The findings of the scanning electron microscopy and energy spectrum analysis suggest that fretting wear between the upper and lower sheets results in fatigue fracture of the lower sheet in the joints. When joining the same material on a large scale, the selection of mechanical clinch over SPR can prove an effective method of reducing costs. Furthermore, the selection of a set of dies with an extended life can contribute to the reduction of joining costs.

An experimental investigation into crashworthiness of filament wound intra-yarn hybrid glass/jute epoxy composites tubes under quasi-static axial and lateral compression

The increasing demand for sustainable materials in the automotive industry has driven the research towards exploration of natural fiber composites for crash structures. This study investigates the quasi-static axial and lateral crushing behavior of hybrid glass/jute fiber epoxy tubes. Intra-yarn hybrid mixing ratios of jute and glass fibers were tested to evaluate the feasibility of using natural fibers as eco-friendly alternatives to traditional synthetic composites. A total of five different configurations were fabricated using filament winding process. The experimental results were analyzed for collapsing behavior, failure modes, and energy absorption characteristics. The hybrid epoxy tubes revealed fiber-matrix fracturing, local buckling, and delamination as three primary failure modes under crushing tests. The hybrid configuration with 25 % jute fiber and 75 % glass fiber demonstrated optimal crashworthiness performance, achieving the highest specific energy absorption (SEA) values of 15.85 J/g under axial loading and 2.96 J/g under lateral loading. The configurations with higher jute content of 50 % and 75 %, showed decreasing SEA and crush force efficiency (CFE) values, with brittle fracturing and delamination as dominant failure modes, indicating a trade-off between weight and energy absorption efficiency. The neat glass fiber configuration maintained nearly consistent CFE values of 0.55 and 0.56, between axial and lateral loadings respectively, demonstrating isotropic behavior in energy absorption. Conversely, the neat jute fiber configuration improved SEA to 12.14 J/g under axial loading but exhibited significant limitations under lateral loading, with SEA decreasing to 0.69 J/g. Visual examination of crushed samples highlighted local buckling in GF configurations and brittle fracturing in hybrid and neat jute fiber configurations. The scanning electron microscope (SEM) analysis provided detailed insights into the microstructural characteristics and failure mechanisms, highlighting the inter-laminar debonding between the jute and glass fibers in hybrid configuration. By evaluating the combined effects of hybridization and loading conditions, the present study contributes to developing eco-friendly and efficient materials for automotive safety, aligning with industry sustainability goals.

The low velocity impact properties of three- dimensional (3D) warp interlock woven composites according to the fabric architecture

Three-dimensional (3D) warp interlock woven composites (3DWIWC) are in demand in various industries due to their excellent delamination resistance, damage tolerance and fracture toughness properties. The 3D warp interlock woven fabric architecture can be defined by numerous fabric parameters such as: the binding and stuffer warp yarns, the woven pattern, the presence of yarn groups, etc. …. The effect of the fabric architecture on the impact behaviour of 3DWIWC made with carbon yarns has not been fully investigated. The binding warp yarns with the weave pattern play the main role in the arrangement of yarns within the final composite. In order to highlight their main influence, the 3D woven composites had been differentiated according to the main fabric architectural parameters, which are the angle and depth of binding warp yarn, presence of stuffer warp yarn and weave pattern of binding warp yarn. Afterward, their low velocity impact properties and damage mechanisms were examined. Thanks to the precise combination of these internal parameters of the fabric architecture, the contact force and absorbed energy values of 3DWIWC could be increased almost %50 and %15, respectively. Moreover, their damage mechanisms could be significantly improved.

The effects of heat treatment on the mechanical properties of 450 HB wear resistant steel

The effects of heat treatment on the mechanical properties of 450 HB wear resistant steel produced by Usiminas steelworks in the form of heavy plates were investigated. The results showed that when tempering temperature is lower than 200°C, there are no significant changes in hardness, tensile properties and absorbed energy in Charpy V-notch test. With further increase in temperature up to 400°C, hardness, tensile strength, total elongation and impact toughness exhibited a slight downward trend. For heating carried out from 400°C to 600°C, a very significant drop in hardness and tensile strength and an increase in total elongation and absorbed energy values were observed. The abrasive wear resistance, evaluated by dry-sand rubber wheel test, increased with the heating up to 500°C. With the additional rise in temperature to 600°C, the abrasive wear resistance decreased, reaching a similar level to the reference state (steel in as-delivered condition).

Effect of v-notch on impact toughness of fibre reinforced laminates produced by fff method

The rapid development of additive technology necessitates identifying opportunities for practical application. For this reason, many experimental measurements have focused on tensile or bending tests, resulting in numerous publications. Previously, the authors evaluated Charpy impact test results to assess the effect of various printing parameters on absorbed energy, using specimens without the notch. However, other studies focused on Charpy impact testing used notched specimens, raising questions about suitability of notch usage for testing of fibre reinforced composites produced by extrusion methods. This paper aims do deal with this question and to evaluate the influence of V-notch on the impact toughness of specimens. For specimens reinforced with chopped carbon fibres, the notch markedly affects impact toughness irrespective of the direction of load orientation (flatwise or edgewise). Conversely, in the case of flatwise loading of specimens reinforced with long HSHT glass fibres, we observed that the notch does not impact the absorbed energy values. However, edgewise impact loading led to decrease of absorbed energy up to 50%. This decrease in absorbed energy can be attributed to the material arrangement in the lamina, as the filament follows the notch, resulting in the formation of inhomogeneities and stress concentrators. In the case of flatwise loading, the notches were created by the lamina layering, so the arrangement of the matrix and fibres in the layer was not affected.

Research on flexural mechanical properties and mechanism of green ecological coir fiber foamed concrete (CFFC)

To explore the effect and mechanism of coir fiber on the performance of foamed concrete, the flexural performance test, pore characteristics and microstructure test of coir fiber foamed concrete with different content were carried out. First, Image-Pro Plus (image processing software) was used to study the pore morphology, porosity, average pore diameter, and pore roundness of CFFC with various fibers dosage (0, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%) by binarization processing method. Then, a total of eighteen specimens, divided into six groups, were used to investigate the effect of CF dosage on flexural strength, toughness, energy absorption, and failure patterns of FC through a three-point flexural test. Furthermore, the microscopic properties of coir fiber foamed concrete (CFFC) were observed by scanning electron microscope (SEM) and energy dispersive X-ray detector (XRD) to explain the influence mechanism of CF on FC flexural properties. According to the research, CF can affect the pore characteristics of CFFC and improve its flexural performance. When CF content is 1.5–2.0%, the porosity, diameter and roundness of CFFC have lower values of 68.6%, 1.96 mm and 1.29. After the fiber dosage reaches 1.5%, the CFFC failure mode changed to plastic damage, the flexural strength increased from 0.33 to 0.73 MPa, and the toughness energy absorption value was increased from 0.05 to 1.4 J. The optimum dosage of coir fiber is 2.0% for improving the flexural mechanical properties of FC. CF affects the process of hydration reaction of CFFC, but does not change the type of hydration product. However, the flexural performance of FC would decrease with excessive dosage of CF (> 2.0%) due to accelerating the formation of Ca(OH)2. CFFC can solve problems such as brittleness and easy cracking existing in traditional foamed concrete, and it can be used in the field of pavement engineering, foundation backfill and lightweight wall structure with CF dosage of 15–2.0%.

Microstructure evolution and mechanical properties of Q690D steel repaired by wire based laser directed energy deposition

ABSTRACT A wire-based laser directed energy deposition process was developed to repair Q690D steel. The microstructure evolution, phase transformation and mechanical properties of the repaired specimens were investigated in detail. Excellent metallurgical bonding was achieved between the repaired zone and the substrate free of macroscopic defects. Typical columnar dendrites with grains grew perpendicularly from the fusion line to the deposition zone (DZ) centre. Microstructure in the DZ and heat-affected zone (HAZ) of the repaired specimen was predominated by lath martensite. The tensile properties of the repaired specimens were comparable to those of the substrate. The repaired specimens presented ∼200 MPa higher flexural strength than that of the substrates, while they have inferior ductility compared to the substrates under the three-point bend test. The average impact absorbed energy value for the repaired specimens achieved ∼85–90% of the substrates. This study introduces a novel restoration technique for offshore engineering platform maintenance.

Effect of the lattice structures on mechanical characterisation of additively manufactured Ti-6Al-4V for biomedical application

ABSTRACT In the last decades, most investigations in titanium bone implantology have applied lattice structures instead of dense materials to reduce weight and obtain the mechanical properties similar to human bones. However, there is still a need for more research on the optimal design of lattice titanium implants with proper mechanical behaviour and heat treatment investigations, which directly affects the mechanical, microstructural, and morphological characteristics. The present study aims to examine the effect of densities and unit cell sizes for Selective Laser Melting (SLM)-printed lattice structures created by MSLattice. TPMS lattice structures including Diamond, Gyroid, and Primitive generated by MSLattice software were subsequently printed using Ti-6Al-4 V ELI. Tensile testing of DTi (dense) produced an ultimate tensile strength of 1241.58 ± 23.92 MPa and a Yield strength of 1151 ± 8.6 MPa, while its compression test resulted in an ultimate value of 1424.8 ± 20.13 MPa. The increase in density from 20% to 30% has resulted in a doubling of some mechanical properties. The lattice structure of the Gyroid at 30% density presented a UCS value of 143.96 ± 0.89 MPa as the highest, while that of the Diamond at 20% density presented the lowest with 46.89 ± 0.43 MPa. The values for energy absorption and plateau stress follow in a precise sequence.

A multifunctional heterogeneous structure inspired by shell brick-mud structure: Balancing noise reduction and mechanical performance

Electric armoured vehicles, which are crucial for strategic operations, must possess superior mechanical properties and noise reduction to maintain normal functionality. However, achieving high energy absorption and noise reduction performance simultaneously is challenging with a single uniform material or structure. This study introduces heterogeneous structures with metal lattice skeletons filled with polymer materials. The skeleton, known as the bionic mantis shrimp structure (BMS), is filled with polyurethane and epoxy. Impedance tube experiments revealed that the sound absorption coefficients of Heterostructure-polyurethane foam (HS-PU) and Heterostructure-epoxy (HS-EP) are significantly higher than BMS. HS-PU achieved an average sound insulation of 33.6 dB, marking a 739 % improvement over BMS. Compression tests show that polymer filling can inhibit the destructive collapse of BMS and enhance its mechanical performance. HS-EP exhibits specific strength and specific energy absorption values of 57 MPa/(g·cm−3) and 30.75 J/g, respectively, representing an increase of 67.6 % and 315 % compared to BMS. Additionally, as the volume fraction of BMS increased in the heterogeneous structure, the elastic modulus and compressive strength increase while the specific energy absorption decreased. This research suggest that the design of metal/polymer heterogeneous structures offers a promising approach for developing high-strength and noise-reducing protective structures.

Characterization of the Gluten Aggregation, Dough Rheological, and Physicochemical Properties of Flours Used in the Production of Flat Breads in Eskişehir

In this study, the physical, chemical, technological, gluten aggregation, and dough rheological properties of flat bread flours (“Bazlama", "Pide", "Gözleme", "Lavash") produced in Eskişehir were evaluated in detail by comparing them with “Bread” flour. The highest SRC lactic acid and GPI (gluten performance indeks) values (118.1% and 0.648, respectively) were found in "Gözleme" flour; however, "Lavash" and "Pide" flours had values close to “Bread” flour. The lowest SRC lactic acid and GPI values were obtained in "Bazlama" flour (84.13% and 0.531, respectively). The protein content of “Lavash” flour was close to bread flour (10.60%), while the protein content of "Pide" and "Gözleme" flours was higher (11.07% and 10.94%, respectively). The protein content of “Bazlama” flour was significantly lower than that of other flours (9.84%). Again, the sedimentation value of “Gözleme” flour was above that of other flours (65.0 ml). Lavash flour also had a high sedimentation value (60.0 ml). The sedimentation values of “Pide” and “Bread” flour were similar (approximately 53.0 ml) and lower. “Bazlama” flour gave a low sedimentation value (43.0 ml). Unlike bread flour, flat bread flours had a gluten indeks (GI) value higher than 90.0%. The ash content of flat bread flours varied between approximately 0.550 and 0.650%. “Bread” flour had the longest GlutoPeak peak maximum time (PMT) (102.0 s). “Bazlama” flour had the lowest torque 15 s before the maximum torque (BM), maximum torque (BEM), torque 15 s after the maximum torque (PM), energy, and water absorption (19,3 BU; 36,3 BU; 22,0 BU; %9,07; %18,57, 26,0 J ve %53,5, respectively). The BEM value of “Lavash”, “Gözleme” and “Pide” flours was higher than bread flour (around 45 BU). Of these three flours, “Pide” and “Lavash” flours maintained their high BEM after 15 s and gave a high PM (37.7 BU and 31.7 BU, respectively). “Bazlama” flour had the lowest PM value (22.0 BU). Particularly, “Gözleme” and “Pide” flours had high gluten-aggregation properties. Although the gluten and protein content values of “Lavash” flour were similar to those of “Bread” flour, its energy and water absorption values were higher (127.3 J and 58.0%). The difference between “Lavash” and “Pide” flours was a short PMT value (around 50 s). “Gözleme” flour had the highest stability (4.15 min.) and the lowest softening degree (49.5 FU) in the farinograph. Farinograph stability, development time, and softening degree values were also better in “Pide” flour (3.05 min., 2.85 min., and 85.0 BU, respectively). The farinograph qulaity number (FQN) values of these two flours were also high (65.5 and 50.0). “Bazlama” flour had low stability, FQN, and high softening degree. The “Bazlama” flour had the highest softening value (243.5 FU). Farinograph rheological properties of “Lavash” and control “Bread” flour were similar to each other. While the G' value of “Gözleme” and “Pide” flours, which were more stable in the farinograph, was found to be higher (27200 Pa and 24525 Pa), the G' value of “Lavash” flour was the lowest (around 12215 Pa). The G' values of “Bazlama” and “Bread” flour were similar (18050 Pa and 16590 Pa). The “Gözleme” and “Pide” flours with higher storage resistance (G') had higher G'' values (around 12000 Pa). “Lavash” flour had the lowest G'' value (6433.5 Pa). The lowest G'' values of “Bazlama” and “Bread” flour were found to be similar. “Gözleme” flour had the lowest Tanδ value (0.464). It is also low in “Pide” flour (0.491). The dough from these flours had an elastic structure. The “Lavash” and “Bazlama” flours had the highest Tanδ value (0.531 and 0.537). As a result, “Lavash” and “Bazlama” flours were found to have weaker and more extensible viscoelastic properties.

Energy absorption of foam-filled TPMS-based tubular lattice structures subjected to quasi-static lateral crushing

Aluminium foam and TPMS-based tubular lattice structures (T-TLS) were of interest due to their superior energy absorption capabilities and inherent lightweight characteristics. However, their synergistic functionality in a composite form remained unexplored. In pursuit of augmenting the crashworthiness characteristics, aluminum foam was filled into T-TLS to form foam-filled T-TLS. FE models were established and validated using lateral crushing experiments. Foam-filled T-TLS exhibited higher energy absorption (EA) compared to the sum of empty T-TLS and foam filler, primarily attributed to the interaction between T-TLS and foam filler. Compared to single circular filled tubes (SCFT) with the same outer sizes and mass, foam-filled T-TLS revealed markedly enhanced crashworthiness, with EA and SEA values being 3.5–3.9 times and 4.0–4.7 times that of SCFT, respectively. Subsequently, parametric investigations underscored the evident influences of relative densities of T-TLS and foam filler, tube thickness and diameter on crashworthiness of foam-filled T-TLS. Finally, a multi-objective optimization was performed to derive optimized configurations by using non-dominated sorting genetic algorithm II (NSGA-II) and radial basis function (RBF) metamodels. In comparison with the baseline designs, the optimal results demonstrated significant enhancements in crashworthiness, with SEA increasing by 173.3 to 206.6 %. The present work provided a new paradigm in the design and development of advanced energy absorbers characterized by high-efficiency energy dissipation under lateral impact scenarios.

Experimental investigation on energy absorption capability of 3D-printed lattice structures: Effect of strut orientation

This experimental study aimed to investigate the effect of strut orientation in various lattice structures that were created using 3D printers on the energy absorption capabilities of the structures. The experiment involved producing three different lattice structures, namely a cube lattice with vertical and horizontal struts, an octet structure with horizontal and 45˚ angled struts, and a body-centered-cubic (BCC) lattice structure with horizontal, vertical, and 45˚ angled struts using the FDM method. Nylon filament mixed with chopped carbon fiber was utilized as filament, and each lattice structure was designed to contain three units in the x and y directions and one and three units in the z-direction. The study conducted axial crushing tests on single-layer and three-layer lattices to determine the energy absorption capabilities of the various lattice structures. The octet lattice demonstrated the highest energy absorption in both single-layer and three-layer samples, making it the most efficient sample. In single-layer lattice samples, the cube and octet structures absorbed 77% and 94% more energy than the BCC structure, which absorbed only 12.8 J. However, the cube structure demonstrated the lowest energy absorption in three-layer samples. This was attributed to the buckling behavior seen in the strut of the lattice structure under axial load. The octet structure had the highest specific energy absorption value in both layers, making it the most energy-efficient sample.

Selective adhesion of nitrogen-containing toxic gasses on hexagonal boron phosphide monolayer: a computational study.

Various toxic gasses are being released into the environment with the increasing industrialization. However, detecting these gasses at low concentrations has become one of the main challenges in environmental monitoring and protection. Thus, developing sensors with high performance to detect toxic gasses is of utmost significance. For this purpose, researchers have introduced 2D materials thanks to their unique electronic qualities and large specific surface area. Within this piece of research, a hexagonal boron phosphide monolayer (h-BPML) is employed as the substrate material. The adhesion behavior of ambient nitrogen-containing toxic gasses, i.e., N2O, NH3, NO2, and NO, onto the h-BPML is investigated through DFT computations. The adhesion energy values for gasses NO and NO2 were calculated to be - 0.509 and - 0.694 eV on the h-BPML, respectively. Meanwhile, the absorbed energy values for gasses NH3 and N2O were found to be - 0.326 and - 0.119 eV, respectively. The recovery time, DOS, workfunction, and Bader charges were computed based on four optimal adhesion structures. After the absorption of NO on the h-BPML, the value of workfunction of a monolayer decreased from 1.54 to 0.47 eV. This amount of decrease was the greatest among the other gasses absorbed. By comparing the investigated parameters, it can be concluded that the h-BPML has a greater tendency to interact with NO gas compared to other gasses, and it can be proposed as a sensor for NO gas. Within this piece of research, the sensitivity of the h-BPML to four nitrogenous toxic gasses, namely, N2O, NH3, NO2, and NO, was investigated using the DFT with HSE06 hybrid functional by using GAMESS software. For this purpose, we computed the DOS, workfunction, and the Bader charges for the four adhesion systems with most stability.