Auxetic materials are a class of materials that expand transversely when stretched longitudinally. Recently, auxetic materials are gaining special interest in wide range of applications mainly due to ...their attractive mechanical behavior. In this study, we focus on the compressive properties of new three-component auxetic composite-filled tubes including empty tubes, auxetic lattice structures and polymer fillers. The compressive behavior of three-component auxetic composite-filled tubes, auxetic composites and empty tube was investigated by means of finite element analysis (FEA) and experimental method. The results indicated that the auxetic composite-filled tubes exhibit superior behavior compared with both the empty tube and auxetic composites, even significantly higher stress than the sum of total thereof. This feature is related to the interaction effect and additional support between the three components. The energy absorption characteristics and deformation modes of the auxetic composite-filled tubes and empty tube were also ascertained. It was concluded that inserting auxetic composite as a filler material inside the empty tube significantly improved its energy absorption, as well as delaying crack initiation and propagation in the empty tube.
The primary treatment strategies for melanoma include surgical excision, chemotherapy, and radiotherapy. However, the efficacy of these treatments is often limited by drug resistance, recurrence, and ...severe side effects. Therefore, we aimed to develop a targeted drug delivery system capable of selectively locating tumor sites to minimize systemic toxicity and enhance therapeutic efficacy. This cell drug delivery system can also deliver chemotherapeutic drugs to the tumor microenvironment.
We treated B16F10 cells with hyperosmotic cold shock (HCS) to obtain and characterize HCS cells. We then investigated the anti-tumor effects and immune activation capabilities of these cells and explored their potential as a targeted drug delivery system.
HCS cells not only maintained an intact cellular structure and tumor antigens but also exhibited high expression of the homologous melanoma-associated antigen glycoprotein 100. These cells demonstrated an exceptional capacity for loading and releasing doxorubicin, which has chemotherapeutic anti-tumor effects. HCS cells can precisely target the tumor microenvironment to minimize systemic toxicity, inducing an immune response by activating CD3+ and CD4+ T cells.
HCS cells are non-carcinogenic, with both cellular and tumor antigens intact; thus, they are suitable drug delivery carriers. Our findings highlight the potential of HCS cells for carrying doxorubicin because of their high drug-loading efficiency, effective tumor-targeting and anti-tumor effects. Therefore, our results will facilitate the development of melanoma treatments that have higher efficacy than those in the literature.
Multi-objective project scheduling has attracted wide attention for approximately two decades. However, most of the existing research has focused on the double-objective project scheduling problem, ...while literature on project scheduling problems with more than two objectives is rather scarce. In this paper, the typical multi-mode resource-constrained project scheduling problem is extended to a new triple-objective multi-mode project scheduling problem (TOMPSP) with the objectives of minimizing the project duration, minimizing the resource investment and maximizing the robustness of the schedule. To solve the presented triple-objective problem, we resort to the latest version of the multi-objective genetic algorithm, the non-dominated sorting genetic algorithm III (NSGA-III). In the decoding process of the NSGA-III, a modified SSGS (serial schedule generation scheme), in which resource constraints are relaxed, is suggested by considering the delays of activities. Although the NSGA-III shows excellent performance in numerous multi-objective optimization problems with more than two objectives, it has a potential disadvantage in that it occasionally cannot find the intercept during the adaptive normalization process, and thus, the population cannot be normalized as expected. Since a case without an intercept is impossible in the NSGA-II, we adopt the NSGA-II normalization process rather than that of NSGA-III. The standard instances in PSPLib are modified to serve as the instances of the TOMPSP, and a computational experiment is conducted to test the algorithms. The results show that the presented algorithm not only greatly simplifies the implementation of the NSGA-III but also significantly improves the execution efficiency and calculation quality.
To improve the service life and total efficiency of the piston pumps, an alloy steel of HMn58-2 manganese brass and 20CrMo are used as the material for a pin–disc, and the change in the coefficient ...of friction of the pin–disc is investigated via a friction/wear experiment. A Plint TE-92 tribometer is used to conduct dry and wet wear experiments on the pin–disc. After the experiments, the friction and macroscopic morphology of the sample are analysed. Results show that the wear in the dry friction experiment is not uniform, the coefficient of friction increases quickly, and the sample wears and fails. When using No. 46 anti-wear hydraulic oil as the lubricant in the friction test, the increase rate of the coefficient of friction is significantly lower than that in the dry friction test. At a rotational speed of 2,000 rpm and a load of 1.1 KN, the maximum coefficient of friction is 0.147. When the load is increased to 1,300 or 1,400 N and the speed is 1,600–2,000 rpm, the coefficient of friction is greater than 0.011. A higher rotational speed results in a smaller coefficient of friction, whereas a greater load results in a higher coefficient of friction, using lubricating oil can significantly reduce the coefficient of friction. The effect of rotational speed on the coefficient of friction is greater than the effect of load.
In this study, a 3D re-entrant anti-trichiral honeycomb (RATH) structure with the combination of various deformation mechanisms was proposed and formed through SLM additive manufacturing. It was ...found that the samples exhibited a good formability with less internal porosity and fine forming accuracy through the macroscopic and microscopic analyse. The microstructure of the fabricated sample present typical characteristics of the SLM-fabricated materials, which includes coarse grain zone, fine grain zone, and heat affected zone. The grains of the as-fabricated sample mainly exhibit the characteristics of columnar grains and the grains with a length up to 41∼86 μm grow from the boundary of one melt pool to another, which are predominantly oriented in the 001 direction and parallel to the forming direction. The quasi-static compression behavior, auxeticity and energy absorption capabilities of the 3D RATH structures with varied geometric parameters are comprehensively investigated through FEA method verified by the experimental results. The numerical results exhibited a good agreement with the experimental results with regard to stress strain behavior, deformation mode and Poisson's ratio. It was found that the compression performance and auxetic behavior of the 3D RATH structures can be tailored by varying the geometrical parameters. The 3D RATH structures exhibit the simultaneous re-entrant and rotating deformations throughout the whole compression process, thereby producing the auxeticity in large strain range. Moreover, the results exhibit that the proposed 3D RATH structures can significantly enhance the compression stress and auxetic behavior by the combination of different structures compared with conventional re-entrant honeycomb structures.
In order to further increase the mechanical properties of auxetic structures, a novel enhanced composite (NEC) auxetic structure was proposed and characterized by the combination of the enhanced ...re-entrant anti-trichiral and double arrow structures. The NEC structures were fabricated from AlSi10Mg powders through selective laser melting (SLM) additive manufacturing technology. The grain morphology and microstructure characteristic of the AlSi10Mg sample were comprehensively analyzed. Results indicate that both columnar and equiaxed grains can be observed in the SLM-fabricated sample. Columnar grains with the size around 52 μm are mainly distributed in the melt pool and equiaxed grains exist at the boundary of the melt pool. The columnar grains are approximately perpendicular to the boundary of the melt pool and grow towards the center of the melt pool, exhibiting filamentous texture. The melt pool boundaries can be divided into three distinct regions, i.e., coarse grain zone, fine grain zone, and heat affected zone. The microstructure of the as-built sample consists of elongate cellular α-Al matrix decorated with eutectic Si network boundaries. The mechanical properties and energy absorption performance are systematically investigated by means of Finite Element Analysis (FEA) verified by the experimental results. It is found that the elastic modulus, compression strength, Poisson's ration and energy absorption of the NEC structures are sensitive to the structure parameters. i.e., the compression stress and energy absorption present an increasing trend with the increasing of α, decreasing of l1 and β, while l1, α and β exhibit opposite effect on the Poisson's ratio. Moreover, the rotational combination of varied structures can lead to an excellent energy absorption capacity of the NEC structures, which is significantly higher than that of other auxetic structures. The results will provide guidance for the structure design of lightweight auxetic structures with enhanced performance and outstanding auxeticity.
New Reentrant Rhombic Auxetic Structures
Xingfu Wang and co‐workers designed and fabricated a new re‐entrant rhombic auxetic structure through 3D printing combined with molten metal infiltration ...technology (see article number 2300347). Structure parametric study proves that the unit configuration exhibits a significant influence on the compression stress, Poisson’s ratio, and energy absorption of the structures. Furthermore, the rhombic auxetic structures present diverse Poisson’s ratios with the structure parameters and compression global strain. The new structures exhibit superior mechanical behavior and energy absorption feature in comparison to the other regular auxetic structures.
In this study, a new reentrant rhombic auxetic structure is first designed by replacing the reentrant strut of the regular reentrant structure with a rhombic structure. A simulation calculation ...method verified by experimental results is comprehensively developed to reveal the compressive behavior of the proposed structures in terms of deformation pattern, compression strength, Poisson's ratio, and energy absorption (EA). Based on the validated simulation method, the results indicate that compression load can give rise to an “X” deformation pattern of the rhombic auxetic structures. In the structure parametric study, it is further proved that the unit configuration exhibits a significant influence on the compression stress and EA of the structures. Furthermore, the rhombic auxetic structures present diverse Poisson's ratios with the structure parameters and compression global strain, that is, the structures with larger H, smaller D, and θ are found to present more pronounced auxetic effect. The compression direction also exhibits a remarkable effect on the performance of the structure, which accordingly indicates the anisotropic characteristic of the proposed structures. Moreover, compared with the other regular auxetic structures, the rhombic auxetic structures exhibit superior mechanical behavior and EA feature due to the introduction of the rhombic structure.
A new reentrant rhombic auxetic structure is first designed and fabricated through 3D printing combined with molten metal infiltration technology method. In the structure parametric study, it is proved that the unit configuration exhibits a significant influence on the compression stress, Poisson's ratio, and energy absorption (EA) of the structures. Moreover, the new structures exhibit superior mechanical behavior and EA feature compared with the other regular auxetic structures.
Herein, the compressive mechanical behavior of novel 3D tetrahedral lattice materials is investigated by ways of experimental, numerical, and analytical methods with a good performance of accuracy. ...Samples with varied length–diameter ratios are fabricated through 3D printing combined with investment casting method. The compressive behavior, deformation characteristic, and energy property of the lattice materials are comprehensively recorded and analyzed with respect to the geometric parameter and compression directions. It is observed that the length–diameter ratio exhibits a significant influence on the mechanical performance and energy absorption of the materials, that is, the lower the length–diameter ratio, the higher the relative density, strength, and energy absorption. Good agreements are observed among the experimental, numerical, and analytical results within a relative acceptable error. Moreover, the mechanical properties and deformation characteristics of lattice materials depend on compression directions to a great extent. In addition, the novel tetrahedral lattice materials with reasonable relative density present superior performance features compared with the other cellular materials.
A novel tetrahedral lattice material is fabricated and the mechanical properties are characterized under compression by means of experimental, numerical, and analytical methods. It is found that the geometric parameter exhibits an important influence on the mechanical properties and energy absorption of the materials. The novel materials with reasonable relative density present superior performance compared with the other cellular materials.
Compared with 2D auxetic metamaterials, 3D auxetic metamaterials present better structural, mechanical, and functional properties, which are more applicable in many potential applications in ...engineering fields. Herein, three types of 3D star‐shaped auxetic (SSA) structures, re‐entrant and star‐shaped composite auxetic (RSA) structures, and star‐rhombic auxetic (SRA) structures with small unit cell are proposed and fabricated by selective laser melting method. The compressive behavior and energy absorption of the auxetic structures are explored and compared based on finite‐element method (FEM) verified by the compression test results of the sample. Meanwhile, the numerical results present good agreements with the experimental results in terms of deformation mode, Poisson's ratio, and compression behavior. The results reveal that SRA structures exhibit superior elastic modulus, compressive strength, and energy absorption than SSA and RSA structures, which stems from the auxetic effect, obstruction of rhombic structures to the deformation of inclined struts and more plastic hinges. It is precisely because of the obstruction of rhombic structures that SRA structures exhibit weakening auxetic characteristic and even no auxetic behavior during the higher strain range. In addition, the length of the structural strut presents a significant impact on the energy absorption performance and compression strength of all the structures.
star‐rhombic auxetic (SRA), star‐shaped auxetic (SSA), and re‐entrant and star‐shaped composite auxetic (RSA structures are proposed and fabricated by selective laser melting (SLM) method. The compressive performance of the structures is explored through finite‐element method (FEM) verified by the experiment. The results reveal that SRA structures exhibit superior mechanical properties than SSA and RSA structures, which stems from the auxetic effect, obstruction of rhombic structures to the inclined struts, and more plastic hinges.
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