基于FKM的增材制造钛合金结构疲劳寿命分析方法研究

基于德国机械工程研究委员会编制的FKM方法,根据已有的试验数据结合有限元仿真计算得到增材制造TA15钛合金材料的相关参数,对增材制造TA15钛合金角盒结构和机加工TA15钛合金角盒结构进行疲劳寿命计算,并对增材制造钛合金角盒结构的疲劳寿命计算结果进行数值分析和试验验证。结果表明,基于FKM方法计算得到的增材制造钛合金角盒结构的疲劳寿命与数值计算结果相比,对数误差在5%以内,与试验寿命相比,对数误差大多在10%以内,基于FKM方法计算得到增材制造钛合金角盒的疲劳寿命高于机加工钛合金角盒结构的疲劳寿命。

Low-temperature characteristicsof rubbers and performance testsof type 120 emergencyvalve diaphragms

Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.

Visualization Analysis of the Impact of Rubber Agroforestry Ecosystem on Soil Microbial Community

Rubber agroforestry systems positively impact soil microbial communities. This study employed a bibliometric approach to explore the research status, hotspots, and development trends related to these effects. Using CiteSpace software, we visually analyzed research literature from the Web of Science (WOS) core database, spanning 2004 to 2024. The focus was on the impact of rubber agroforestry ecosystems on soil microbial communities. The results indicate significant attention from Chinese researchers, who have published numerous influential papers in this field. Authors Liu Wenjie have contributed the most papers, although no stable core author group exists. The Chinese Academy of Sciences is the leading research institution in terms of publication volume. While there is close collaboration between different institutions and countries, the intensity of researcher cooperation is low. The most cited literature emphasizes soil nutrients and structure in rubber agroforestry, laying a foundation for soil microorganism studies. Most cited journals are from countries like Netherlands and the United Kingdom. Key research areas include the effects of rubber intercropping on soil microbial communities, agroforestry management, and soil health. Research development can be divided into three stages: the initial stage (2010-2015), the development stage (2015-2020), and the mature stage (2020-2024). Current studies show that rubber intercropping and rubber-based agroforestry systems enhance soil microbial communities, positively impacting soil health. This paper provides a theoretical basis for the sustainable development of rubber agroforestry systems and improved management plans. Future research could explore the effects of species composition on soil microbiological characteristics and develop methods for species interactions. An in-depth study of the soil microbial community’s structure and function, and its relationship with rubber trees, is crucial. Developing effective, rationally designed rubber agroforestry systems and underground soil microbiome technology will promote sustainability and improve plantation productivity.

Physical and Chemical Characterizations of Rubber Latex Cup Bottom Oil

Rubber latex is an important economic resource. However, the residues from its harvesting are thrown away, even though they contain lipids that can be recycled. This recovery of the residues from the bottom of the cup requires first and foremost their characterization. The aim of this study is therefore to determine the main physical and chemical characteristics of rubber latex cup bottom oil. Oil’s physical parameters determination shows that it has a density of 951 kg∙m−3, a kinematic viscosity of 48.57 cSt and a water content of 0.0845%. Chemical parameters, meanwhile, indicate that this cup bottom residue has a fat content of 95.96%, an acid number of 2.805 mg KOH/g and an iodine number of 92.42 g I2/100g. Therefore, rubber latex cup bottom oil can be used in the formulation of biofuels, biolubricants, paints, varnishes, alkyd resins, polishing oils, soaps, and insecticides.

Effect of modified aramid nanofiber on compatibilization of natural rubber/epoxidized natural rubber composites

The combination of natural rubber(NR)with epoxidized natural rubber(ENR)could improve the wet slid resistance,mechanical properties,abrasion resistance and thermo-oxidative aging resistance of NR,which showed important research significance.Aramid nanofiber,as a new nano filler for polymer developed in recent years,had the advantages of both macroscopic fibers and polymer nanomaterials.The NR/ENR composites were prepared by dry mixing with NR and the pre-composite prepared from ENR latex and the modified aramid nanofibers(t-ANF).

Effect of graphene oxide with different oxidation degrees on mechanical properties of styrene-butadiene rubber: Experiment and molecular simulation

Graphene oxide(GO)has proven to be an effective reinfor-cing filler for rubber[1].GO has superior mechanical properties,barrier properties,large specific surface area and abundant oxygen-containing functional groups[2].However,the change in the oxidation degree of GO has a great effect on its chemical properties,the interaction between GO and the matrix,and the dispersion uniformity in the rubber matrix,which has a great effect on the reinforcement of rubber[3].

Transient NOE driven signal enhancement of INADEQUATE solid-state NMR spectroscopy for the structural analysis of rubbers

INADEQUATE(Incredible Natural Abundance DoublE QUAntum Transfer Experiment)is one of the most important techniques in revealing the carbon skeleton of organic solids in solid-state NMR spectroscopy.Nevertheless,its use for structural analysis is quite limited due to the low natural abundance of^(13)C-^(13)C connectivity(~0.01%)and thus low sensitivity.Particularly,in semi-solids like rubbers,the sensitivity will be further significantly reduced by the inefficient cross polarization from 1H to^(13)C due to molecular motions induced averaging of^(1)H-^(13)C dipolar couplings.Herein,in this study,we demonstrate that transient nuclear Overhauser effect(NOE)can be used to efficiently enhance^(13)C signals,and thus enable rapid acquisition of two-dimensional(2D)^(13)C INADEQUATE spectra of rubbers.Using chlorobutyl rubber as the model system,it is found that an overall signalto-noise ratio(SNR)enhancement about 22%can be achieved,leading to significant timesaving by about 33%as compared to the direct polarization-based INADEQUATE experiment.Further experimental results on natural rubber and ethylene propylene diene monomer(EPDM)rubber are also shown to demonstrate the robust performance of transient NOE enhanced INADEQUATE experiment.

Seismic evaluation of frequency influence and resonant behavior for lead rubber bearing isolated rigid rectangular liquid tanks

The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded quadrilateral elements.The competency of the model is verified with the available results.Parametric studies are conducted for the dynamic parameters of the base-isolated tank,using a lead rubber bearing to evaluate the optimum damping and time period of the isolator.The application of base isolation has reduced the total and impulsive hydrodynamic components of pressure by 80 to 90 percent,and base shear by 15 to 95 percent,depending upon the frequency content and duration of the considered earthquakes.The sloshing amplitude of the base-isolated tank is reduced by 18 to 94 percent for most of the short-duration earthquakes,while it is increased by 17 to 60 percent for the majority of the long-duration earthquakes.Furthermore,resonance studies are carried out through a long-duration harmonic excitation to obtain the dynamic behavior of non-isolated and isolated tanks,using a nonlinear sloshing model.The seismic responses of the base-isolated tank are obtained as higher when the excitation frequency matches the fundamental sloshing frequency rather than the isolator frequency.

Discussion on“Dispersion characteristics of clayey soils containing waste rubber particles”[J Rock Mech Geotech Eng 15(2023)3050-3058]

We read with great interest the recent article by Erenson(2023)entitled“Dispersion characteristics of clayey soils containing waste rubber particles”.The author has studied the dispersion characteristics of clayey soils containing different percentages of waste rubber particles(WRPs)by performing several tests(viz.consistency limit,linear shrinkage limit,double hydrometer,crumb test and pinhole test)and scanning electron microscopy(SEM)analysis on five clayey(viz.Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin and Afyon clay)samples containing 0%,5%,10%and 15%WRPs.It should be noted that Erenson(2023)has presented some interesting observations,but there are some serious issues that we want to share through this discussion and request the author of the original paper to address them to avoid their persistence in the scientific literature.

Mechanical behavior of nanorubber reinforced epoxy over a wide strain rate loading

Nanorubber/epoxy composites containing 0,2,6 and 10 wt%nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8×10^(-4) s^(-1) to~2×10^(4) s^(-1).Unexpectedly,their strain rate sensitivity and strain hardening index increase with increasing nanorubber content.Potential mechanisms are proposed based on numerical simulations using a unit cell model.An increase in the strain rate sensitivity with increasing nanorubber content results from the fact that the nanorubber becomes less incompressible at high strain,generating a higher hydro-static pressure.Adiabatic shear localization starts to occur in the epoxy under a strain rate of 22,000 s^(-1) when the strain exceeds 0.35.The presence of nanorubber in the epoxy reduces adiabatic shear localization by preventing it from propagating.

Hand Cooling Enhances the Proprioceptive Drift during Rubber Hand Illusion

Background: The neural representation of the body is easily altered by integrating multiple sensory signals in the brain. The “Rubber Hand Illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, ownership of a rubber hand is temporarily induced. It was shown that external and continuous cooling of the palm enhanced the RHI, suggesting an association between altered the autonomic nervous system regulation and altered the sense of ownership of a specific limb. Purpose: To investigate whether artificially cooling the entire hand for a short period affects the magnitude of the illusion. Methods: Participants immersed their entire hand in cool, cold, or warm water for 1 min before the RHI procedure. Results: We found that cooling the entire hand enhanced the proprioceptive drift during the RHI but not the subjective feeling of ownership. In contrast, warming and intense cooling of the entire hand did not affect the RHI strength. Conclusion: Our results suggest that transient and moderate cooling of the entire hand was sufficient in enhancing the illusory disembodiment of one’s own hand.

Natural rubber latex as a potential additive for water-based drilling fluids

The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals.This paper explored for the first time the interaction mechanism between natural rubber latex(NRL)and bentonite suspensions(BTs)through a series of characterization experiments,as well as the potential applications in water-based drilling fluids(WBDF).The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient(k)and flow index(n)of BTs,and enhance the shear thinning performance of BTs as pseudo-plastic fluids.In addition,0.5 w/v%NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles,but also facilitated the compatibility of pressure loss and flow efficiency.The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles,and optimize the particle size distribution and flow resistance of WBDF under the"intercalation-exfoliation-encapsulation"synergistic interaction.Moreover,NRL can improve the rheological properties of WBDF at high temperatures(<150.C),and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake,which ultimately reduces the permeability of the cake and the filtration loss of WBDF.

Comparison of nonlinear modeling methods for the composite rubber clamp

The cubic stiffness force model(CSFM)and Bouc-Wen model(BWM)are introduced and compared innovatively.The unknown coefficients of the nonlinear models are identified by the genetic algorithm combined with experiments.By fitting the identified nonlinear coefficients under different excitation amplitudes,the nonlinear vibration responses of the system are predicted.The results show that the accuracy of the BWM is higher than that of the CSFM,especially in the non-resonant region.However,the optimization time of the BWM is longer than that of the CSFM.

Solid-state NMR of vulcanized natural rubber/butadiene rubber blends:Local organization and cross-linking heterogeneities This article is part of the virtual special issue“Solid-state NMR studies on polymers and biological solids”

Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other features,a detailed description of the crosslink density in these mixtures.In the case of vulcanized immiscible blends,the distribution of the cross-link density within each of the NR-and BR-rich domains is key information,but difficult to determine using the conventional approaches used for one-component crosslinked elastomers.In this study,the vulcanization within NR/BR blends is investigated using a robust^(1)H double-quantum(DQ)MAS recoupling experiment,BaBa-xy16.Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component.The bulk organization of the resulting blends was first probed by analyzing the^(1)H spin-lattice relaxation behavior.In a second step,BaBa-xy16 was used to investigate,in a selective way,the cross-link heterogeneities within NR/BR blends.In particular,for immiscible NR/BR mixtures,the distribution of the cross-link density between both phases was compared and the observed differences were discussed.

基于FKM标准的转向架构架疲劳强度评估

随着车辆速度的提升及振动程度的加剧,转向架焊接部位极易发生疲劳破坏,因此选用较为科学的疲劳评估标准非常重要。文章以某高速动车组拖车转向架构架为例,综合UIC 515-4和EN 13749标准要求进行超常载荷和模拟运营载荷等工况分析,依据分析结果选取疲劳评估点,并分别应用FKM标准和修正的Goodman-Smith曲线进行疲劳强度评估和对比分析。结果表明:FKM标准可应用于轨道车辆各结构的疲劳强度评估,且评估过程更为科学合理,评估结果更为保守可靠。

Blue rubber blister nevus syndrome: A case report

BACKGROUND Blue rubber blister nevus syndrome(BRBNS)is a congenital,rare disease charac-terized by venous malformations of the skin and internal organs,affecting all systems throughout the body.The pathogenesis is unknown.There is no con-sensus on the treatment of BRBNS.Most of the previously reported cases were mild to moderate with a good prognosis,and this case was a critically ill patient with severe gastrointestinal hemorrhage,disseminated intravascular coagulation(DIC),and severe joint fusion that was different from previously reported cases.CASE SUMMARY An 18-year-old man with early onset of BRBNS in early childhood is reported.He presented with recurrent melena and underwent malformed phlebectomy and partial jejunectomy and ileal resection.The patient had melena before and after surgery.After active treatment,the patient's gastrointestinal bleeding improved.This was a case of atypical BRBNS with severe gastrointestinal bleeding and severe joint fusion,which should be differentiated from other serious joint lesions and provide clinicians with better understanding of this rare disease.CONCLUSION This case of critical BRBNS with gastrointestinal hemorrhage,DIC and severe joint fusion provides further understanding of this rare disease.

Ethylene and jasmonate as stimulants of latex yield in rubber trees(Hevea brasiliensis):Molecular and physiological mechanisms.A systematic approximation review

The rubber tree Hevea brasiliensis(Willd.Ex Adr.De Juss.)Müell Arg.]is an important source of latex for the production natural rubber.Natural rubber is an important biopolymer used in various industries,but aspects related to hormonal regulation in biosynthesis are still unknown,which would allow optimizing its production.We review the molecular and physiological mechanisms of increases latex regeneration and flow by the stimulation of rubber trees with exogenous applications of ethylene and jasmonate.We found that the increase in latex regeneration by ethylene is due to the increase in gene level expression and enzymatic activity of key photosynthesis and glycolysis enzymes for the generation of precursors in the first phase of rubber biosynthesis.Latex flow is supported by up-regulated genes in sucrose metabolism such as invertases,induction of sucrose transporters(SUT),and aquaporins(PIP)to maintain flow and turgor pressure in laticifers.Meanwhile,the increase in latex yield mediated by jasmonate may be due to the induction of laticifer differentiation in the long term and in the short term be mediated by the induction of small rubber particles(SRPP)as non-enzymatic cofactors in the production of latex.This information contributes to the knowledge of latex biosynthesis,which allows for a greater support for the exogenous application of jasmonates and ethylene to regulate its production.

Lexical Characteristics and Translation Strategies of Rubber and Plastic Industry Terms

As a key part of the manufacturing industry,the rubber and plastic industry is widely used in a variety of fields such as automotive manufacturing,construction materials,and electronics.With technological innovation,global economic growth and infrastructure construction driving the demand for rubber and plastic materials,rubber and plastic materials play an important role in various fields,and accurate translation of the industry’s terminology is also crucial for international communication.The purpose of this paper is to explore in depth the lexical features of rubber and plastic industry terminology,including strong specialization,specialization of common vocabulary,and diversity of word formation.In view of these lexical features,relevant Chinese translation strategies are discussed to ensure the accuracy,specialization and comprehensibility of the translation of rubber and plastic industry terms.

基于简易冲击分解模型的爆轰驱动硅橡胶数值模拟及实验解读

为了反映爆轰驱动下硅橡胶发生冲击分解反应的物理过程,提出了一种简易的硅橡胶冲击分解模型。基于该模型,对爆轰驱动含硅橡胶夹层钢板实验进行了模拟,并分析解读了钢板的自由面速度。结果表明,实验中硅橡胶发生了冲击分解反应,导致钢板的自由面速度曲线出现了首次起跳中间速度平台及首次起跳速度峰值降低的现象。受硅橡胶冲击分解影响,首次入射波压力将在临界冲击分解压力附近弛豫一段时间,再继续升高至最高压力。该压力波作用于钢板的自由面后,出现了自由面速度在中间速度平台停留一段时间,之后继续升高至速度峰值的现象。硅橡胶冲击分解后的气相物质可压缩性较高,首次加载波内较多的能量被用于压缩气体做功,导致首次波传播至自由面时能量衰减,峰值压力降低,首次起跳速度峰值降低。

无机填料对硅橡胶基耐热复合涂层的影响

以硅橡胶为基体,添加无机填料制备的耐热涂层在耐热防腐方面有重要应用前景。采用自制改性硅橡胶作基体,添加不同配比的高岭土、二氧化硅和氧化铝,制备了复合涂层。采用扫描电子显微镜(scanning electron microscopy,SEM)观察了硅橡胶基体中无机填料的分散状况,采用热重分析仪(thermogravimetric analyzer,TGA)对复合涂层的热解温度和失重率进行了分析。结果表明:在复合体系中,无机填料与基体的相容性较好,分散均匀;与基体材料相比,无机填料的添加可有效提高复合材料的耐热性。填料质量分数为20%的复合涂层,其在800℃时质量残留率比自制改性硅橡胶的基体提高了10%以上。