Effects of Sinusoidal Vibration of Crystallization Roller on Composite Microstructure of Ti/Al Laminated Composites by Twin-Roll Casting

A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality.

Theoretical and experimental investigation of the resonance responses and chaotic dynamics of a bistable laminated composite shell in the dynamic snap-through mode

The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic behaviors.The existence of the 1:1 resonance relationship between two order vibration modes of the system is verified.The resonance response of this class of bistable structures in the dynamic snap-through mode is investigated,and the four-dimensional(4D)nonlinear modulation equations are derived based on the 1:1 internal resonance relationship by means of the multiple scales method.The Hopf bifurcation and instability interval of the amplitude frequency and force amplitude curves are analyzed.The discussion focuses on investigating the effects of key parameters,e.g.,excitation amplitude,damping coefficient,and detuning parameters,on the resonance responses.The numerical simulations show that the foundation excitation and the degree of coupling between the vibration modes exert a substantial effect on the chaotic dynamics of the system.Furthermore,the significant motions under particular excitation conditions are visualized by bifurcation diagrams,time histories,phase portraits,three-dimensional(3D)phase portraits,and Poincare maps.Finally,the vibration experiment is carried out to study the amplitude frequency responses and bifurcation characteristics for the bistable laminated composite shell,yielding results that are qualitatively consistent with the theoretical results.

Snap-through behaviors and nonlinear vibrations of a bistable composite laminated cantilever shell:an experimental and numerical study

The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell.

Dynamic and electrical responses of a curved sandwich beam with glass reinforced laminate layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact

The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.

Study of damage behavior and repair effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading

Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair technique.Damage evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]s.Quasi Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection technique.Damaged laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged hole.Four different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI test.The results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine laminates.Patches of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine laminates.Furthermore,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.

Ballistic penetration damages of hybrid plain-woven laminates with carbon,Kevlar and UHMWPE fibers in different stacking sequences

Hybrid composite materials combine different fibers in preform and take advantages of different mechanical behaviors for improving ballistic impact damage tolerances.Here we report ballistic impact damages of plain-woven laminates with different hybrids and stacking sequences.Three kinds of hybrid laminates,i.e.,carbon/Kevlar,carbon/ultra-high molecular weight polyethylene(UHMWPE),and UHMWPE/Kevlar,had been prepared and tested in ballistic penetration with fragment simulating projectiles(FSP).The residual velocities of the projectiles and impact damage morphologies of the laminates have been obtained to show impact energy absorptions for the different hybrid schemes.A microstructural model of the hybrid laminates had also been established to show impact damage mechanisms with finite element analysis(FEA).We found that the UHMWPE/Kevlar hybrid laminates with Kevlar layers as the front face have the highest energy absorption capacity,followed by the carbon/Kevlar hybrid laminates with carbon layers as the front face.The main damage modes are fiber breakages,matrix crack and interlayer delamination.The ballistic damage evolutions from the FEA results show that the major damage is shear failure for front layers,while tension failure for the back layers.We expect that the ballistic impact performance could be improved from the different hybrid schemes.

Multi-stage penetration characteristics of thick ultra-high molecular weight polyethylene laminates

To further reveal the failure mechanisms of thick ultra-high molecular weight polyethylene(UHMWPE)laminates,field firing tests were conducted for 10-,20-,and 30-mm thick laminates against 12.7-mm calibre wedge-shaped fragment simulated projectiles at high velocities between 450 and 1200 m/s.The ballistic performance,deformation process,and staged failure characteristics of the laminates with different thicknesses were compared and analysed.The results demonstrate that the ballistic limits of the UHMWPE laminates increase almost linearly with laminate thickness.The 10-mm thick laminate generally experiences two-stage failure characteristics,whereas three-staged failure occurs in the 20-and 30-mm thick laminates and the progressive delamination is evident.The energy limit concept representing the maximum energy absorption efficiency and the idea of reuse of the thick UHMWPE laminates are proposed in this study.The findings of this research will be useful in the design of flexible and effective UHMWPE-based protective equipment.

Dynamic analysis of bio-inspired helicoid laminated composite plates resting on Pasternak foundation excited by explosive loading

This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF)excited by explosive loading.IGA takes advantage of non-uniform rational Bspline(NURBS)basic functions to exactly represent the structure geometry models and the attainment of higher-order approximation conditions.This method also ensures a C1 continuous function in the analysis of transverse shear deformation via HSDT.Furthermore,IGA eliminates the requirement for correction factors and delivers accurate results.Pasternak foundation with two stiffness parameters:springer stiffness(k_(1))and shear stiffness(k_(2)).The derivation of the governing equations is based on Hamilton's principle.The proposed method is validated through numerical examples.A comprehensive analysis of the impact of geometrical parameters,material properties,boundary conditions(BCs),and foundation stiffness on dynamic response of B-i HLC plates is carried out.

Vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers under blast load

In this article,vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers subjected to blast load are studied.Higher-order ES-MITC3 element based on higher-order shear deformation theory(HSDT)to achieve the governing equations.The sandwich plates with the ultra-light feature of the auxetic honeycomb core layer(negative Poisson’s ratio)and reinforced by two laminated three-phase skin layers.The obtained results in our work are compared with other previously published to confirm accuracy and reliability.In addition,the effects of parameters such as geometrical and material parameters on the vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers are fully investigated.

Effects of Hydrothermal Environment on the Deformation of the Thin Bamboo Bundle Veneer Laminated Composites

To overcome warping in thin bamboo bundle veneer laminated composites(TBLC),their hydrothermal deformation characteristics were systematically investigated in this study.It was found that TBLCs accelerated the release of internal stress in the thickness direction in a hydrothermal environment,which increased their warpage.TBLCs showed increased warpage in the width and diagonal directions upon increasing the temperature.The warpage of Type E increased by 155.88%and 66.67%in the width and diagonal directions,respectively,when the temperature increased from 25
C to 100
C.The symmetrical TBLC with cross-lay-up and odd layers displayed better hydrothermal stability.We revealed that the deformation of the TBLCs could be regulated under the synergistic effect of water and temperature.These results provide a scientific basis for improving the uniformity of bamboo bundle composite materials and for developing thin bamboo bundle fiber composite materials with designable structures and controllable performance.

Investigation of Various Laminating Materials for Interior Permanent Magnet Brushless DC Motor for Cooling Fan Application

Permanent magnet brushless DC motors are used for various low-power applications,namely domestic fans,washing machines,mixer grinders and cooling fan applications.This paper focuses on selecting the best laminating material for the interior permanent magnet brushless DC(IPM BLDC)motor used in the cooling fan of automobiles.Various laminating materials,namely M19-29GA,M800-65A and M43,are tested using finite element analysis.The machine's vital performance metrics,namely the stator current,torque ripple,and hysteresis loss were analyzed in selecting the laminating material.The designed motor is also modelled as a mathematical model from the computed lumped parameters.The performance of the machines was validated through electromagnetic and thermal analysis.

Effect of Molding Technique That Move Model Position Just before Formation in Production of Laminated Mouthguard

Many molding techniques have been researched to ensure the thickness of custom mouthguards. The aim of this study was to clarify the effect on the thickness of a laminated mouthguard of a molding technique in which the model position is moved forward just before molding. Mouthguards were molded using a 3.0-mm-thick ethylene vinyl acetate mouthguard sheet and a pressure molding machine. The molding method was the normal molding method (condition C) and the molding technique (condition MP) in which the model position was moved 20 mm forward just before molding. Regarding the molding of the first layer (F) and the second layer (S), the following four molding methods based on the combination of conditions C and MP were compared;FC-SC, FC-SMP, FMP-SC, and FMP-SMP. Differences in mouthguard thickness due to molding conditions for the first and second layers were analyzed by two-way ANOVA and Bonferroni’s multiple comparison test. Significant differences were observed among all molding conditions on the labial surface, and the thicknesses were in the order FC-SC < FC-SMP < FMP-SC < FMP-SMP. FMP-SMP was 4.67 mm thick, which was 1.39 mm thicker than FC-SC. FC-SC was the thinnest at the cusp, and a significant difference was observed between other molding conditions. On the buccal side, significant differences were observed between all conditions except FC-SMP and FMP-SC, and the thicknesses were in the order FC-SC < FC-SMP, FMP-SC < FMP-SMP. The results of this study suggested that the labial and buccal sides of laminated mouthguards could be made 1.4 and 1.2 times thicker when a molding technique that moves the model position just before formation was used for the first and second layers. The reduction in thickness was suppressed by approximately 23.2% and approximately 10.7% on the labial and buccal sides, respectively, compared with the normal molding method.

Two-dimensional analyses of delamination buckling of symmetrically cross-ply rectangular laminates

The conventional approach to analysis the buckling of rectangular laminates containing an embedded delamination subjected to the in-plane loading is to simplify the laminate as a beam-plate from which the predicted buckling load decreases as the length of the laminate increases. Two-dimensional analyses are employed in this paper by extending the one-dimensional model to take into consideration of the influence of the delamination width on the buckling performance of the laminates. The laminate is simply supported containing a through width delamination. A new parameterβ defined as the ratio of delamination length to delamination width is introduced with an emphasis on the influence of the delamination size. It is found that （i） when the ratio β is greater than one snap-through buckling prevails, the buckling load is determined by the delamination size and depth only; （ii） as the ratio β continues to increase, the buckling load will approach to a constant value. Solutions are verified with the well established results and are found in good agreement with the latter.

VEGF和miR-205及靶蛋白Ezrin和LaminA/C在卵巢癌中的表达及意义

目的:分析血管内皮生长因子(vascular endothelial growth factor,VEGF),miR-205,Ezrin,Lamin A/C在卵巢癌组织中的表达及意义。方法:采用酶联免疫吸附测定(enzyme-linked immunosorbent assay,ELISA)检测卵巢癌患者和正常女性血清中VEGF的含量;免疫组织化学检测上皮性卵巢癌组织、卵巢良性肿瘤组织和正常卵巢组织中血管内皮细胞生长因子受体-1(vascular endothelial cell growth factor receptor-1,VEGFR-1),VEGFR-2,Ezrin,Lamin A/C蛋白的表达情况和CD31所标记的微血管密度(microvessel density,MVD);采用荧光定量PCR方法检测卵巢上皮性癌组织、卵巢良性肿瘤组织和正常卵巢组织中miR-205,Ezrin和Lamin A/C的相对表达量。结果:VEGF在上皮性卵巢癌患者血清中的表达水平为(116.10±11.94),高于正常女性(40.04±4.97,P<0.05);VEGFR-1和VEGFR-2在卵巢上皮性癌组织中的阳性表达率分别为75.9%和91.4%,高于卵巢良性肿瘤组织和正常卵巢组织中的阳性表达率(P<0.05),VEGFR-1和VEGFR-2在卵巢良性肿瘤组织和正常卵巢组织中的表达差异无统计学意义(P>0.05);MVD在上皮性卵巢癌组织中的计数为(7.56±0.51),高于正常卵巢组织(1.22±0.56,P<0.05),MVD在卵巢良性肿瘤组织和正常卵巢组织中的表达差异无统计学意义(P>0.05);miR-205在上皮性卵巢癌组织中的相对表达量为(0.106±0.035),高于正常卵巢组织中的相对表达量(0.0007±0.0005,P<0.05),miR-205在卵巢良性肿瘤组织中的相对表达量为(0.0002±0.0003),高于正常卵巢癌组织中的相对表达量,但差异无统计学意义(P>0.05);免疫组织化学结果显示:Ezrin和Lamin A/C在上皮性卵巢癌组织中的阳性表达率分别为51.7%和60.3%,低于卵巢良性肿瘤组织和正常卵巢组织中的阳性表达率(P<0.05),Ezrin和Lamin A/C在卵巢良性肿瘤组织和正常卵巢组织中的表达差异无统计学意义(P>0.05);RT-PCR结果显示:Ezrin和Lamin A/C在上皮性卵巢癌组织中的相对表达量低于正常卵巢组织中的相对表达量(P<0.05);Ezrin和Lamin A/C在卵巢良性组织中的相对表达量高于在上皮性卵巢癌组织,但差异无统计学意义(P>0.05)。结论:VEGF在上皮性卵巢癌患者血清中表达上调;miR-205在上皮性卵巢癌组织中表达上调;差异蛋白Ezrin和Lamin A/C在上皮性卵巢癌组织中表达下调,提示VEGF和miR-205及靶蛋白Ezrin和Lamin A/C与卵巢癌的侵袭、转移相关。

益气除痰方降低肺癌Caspase 6、Lamin B1表达诱导细胞凋亡的机制

目的研究益气除痰方对肺癌A549裸鼠移植瘤天冬氨酸特异性半胱氨酸蛋白酶6(Caspase 6)及核纤层蛋白B1(Lamin B1)表达的影响。方法选用BALB/c裸小鼠40只,将肺癌A549细胞悬液接种于小鼠背侧皮下建立肺癌模型,接种第7天将小鼠随机分为5组,即模型组(生理盐水组),顺铂注射液组(0.002 g/kg),益气除痰方低、高剂量组(3.0、6.0 g/kg),联合用药组(3.0 g/kg益气除痰方+0.002 g/kg顺铂),每组8只。中药灌胃,每天1次连用21 d;顺铂注射液腹腔注射,每天1次,连用7 d。干预第22天,处死所有小鼠,测量瘤体质量、体积,并采用免疫组化及RT-PCR法检测肿瘤组织中Caspase 6、Lamin B1的表达。结果益气除痰方高剂量组和联合用药组肿瘤体积、肿瘤质量明显下降,免疫组织化学法及RT-PCR法检测结果显示,肿瘤组织中Caspase 6、Lamin B1的表达均降低,与模型组比较,差异有显著性(P<0.01);联合用药组与顺铂注射液组比较,差异有显著性(P<0.05)结论益气除痰方可抑制小鼠A549肺癌,与化疗药物联用有一定的增效作用,其机制可能与通过降低Caspase 6Lamin B1的表达诱导细胞凋亡有关。

Lamin B1在邻苯二甲酸二丁酯致大鼠尿道下裂发生中的表达变化

目的:利用邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)胚胎晚期暴露导致SD胎鼠尿道下裂发生的动物模型,验证Lamin B1在尿道下裂与正常胎鼠阴茎中的差异表达,以进一步探讨尿道下裂的发生机制。方法:妊娠14～18天SD雌鼠20只,随机分为2组,实验组和对照组分别给予DBP800mg/(kg·d)和大豆油2ml/d灌胃,孕期第19天剖宫产后记录雄性胎鼠肛门和生殖器之间的距离(AGD)、出生体重(BW)及尿道下裂发生数,取雄性胎鼠阴茎,运用免疫印迹法和免疫组织化学方法分析Lamin B1的表达情况。结果:实验组AGD/BW与对照组相比有显著性差异(P<0.05);尿道下裂发生率为40%;Lamin B1在对照组的相对表达量为0.923±0.013(n=10),实验组为0.593±0.014(n=10),差异有统计学意义(P<0.05);Lamin B1主要定位于尿道上皮细胞,对照组染色强度明显强于实验组。结论:DBP灌胃期间改变了尿道组织中Lamin B1的表达,影响了细胞迁移和尿生殖褶的融合,这可能是尿道下裂发生的原因之一。

Nonlinear progressive damage model for composite laminates used for low-velocity impact

In order to effectively describe the progressively intralaminar and interlam- inar damage for composite laminates, a three dimensional progressive damage model for composite laminates to be used for low-velocity impact is presented. Being applied to three-dimensional （3D） solid elements and cohesive elements, the nonlinear damage model can be used to analyze the dynamic performance of composite structure and its failure be- havior. For the intralaminar damage, as a function of the energy release rate, the damage model in an exponential function can describe progressive development of the damage. For the interlaminar damage, the damage evolution is described by the framework of the continuum mechanics through cohesive elements. Coding the user subroutine VUMAT of the finite element software ABAQUS/Explicit, the model is applied to an example, i.e., carbon fiber reinforced epoxy composite laminates under low-velocity impact. It is shown that the prediction of damage and deformation agrees well with the experimental results.

LaminB1蛋白在食管鳞癌组织中表达的形态学观察

目的探讨laminB1蛋白在食管鳞癌患者的癌组织及上切缘正常粘膜上皮中表达的形态变化。方法制备组织切片原位核基质,应用免疫组化的方法检测核基质制备前后正常粘膜上皮及癌组织中laminB1的表达;同时提取组织核基质蛋白,应用Westen blot检测核基质蛋白中laminB1的表达。结果正常食管粘膜上皮及食管鳞癌组织核基质制备前后laiminB1表达的阳性率分别为:正常粘膜上皮93.3%、正常粘膜上皮核基质86.7%、癌组织96.7%、癌核基质86.7%。正常粘膜上皮laminB1表达阳性细胞从基底层至颗粒层逐渐减少,制备核基质后正常粘膜上皮核基质laminB1表达阳性细胞数目减少、强度明显减弱,阳性细胞集中于基底层,多数细胞整个胞核着色。癌组织laminB1表达阳性细胞散在分布,无规律;癌核基质laminB1表达阳性强度减弱,阳性颗粒在核周较集中。癌核基质laminB1表达的阳性强度比正常粘膜上皮核基质高,差异有显著性(x2=5.042,P<0.05)。Western blot检测显示正常粘膜核基质的laminB1条带比癌核基质弱。结论laminB1蛋白在食管正常粘膜上皮及食管鳞癌组织中广泛存在。制备核基质后,laminB1蛋白在癌核基质的表达比正常粘膜上皮核基质强;且癌核基质中laminB1的分布与正常粘膜上皮核基质存在差异。

Low velocity impact studies of E-glass/epoxy composite laminates at different thicknesses and temperatures

Low velocity impact experiments were carried out on E-glass/epoxy composite laminates having varying thicknesses at sub zero and elevated temperatures using hemi spherical steel impactor of 16 mm diameter with impact energies in the rage of 50-150 J.The performance of the laminates was assessed in terms of energy absorption,maximum displacement,peak force and failure behaviour.Results indicated that the effect of temperature on energy absorption of the laminate is negligible although the laminates are embrittling at sub zero temperatures.However it has influence on failure behaviour and displacement.Peak force has increased linearly with increase in laminate thickness from 5 to 10 mm.However it got reduced by 25% when temperature was increased from-20℃ to 100℃,Based on experimental results,laminate perforation energies were predicted using curve fitting equations.Statistical analysis was carried out using Taguchi method to identify the global effects of various parameters on laminate performance and confirmed that the laminate thickness has significant influence as compared to temperature,for the studied range.

Experimental and simulation studies on delamination strength of laminated glass composites having polyvinyl butyral and ethyl vinyl acetate inter-layers of different critical thicknesses

The laminated glasses(LGs)composites are gaining popularity as protectivestructural material. Delamination strength(DS) of(LGs) with different inter-layers and their different nominal thicknesses were compared. The effect of inter-layer thickness, delamination load, and inter-layer type on DS is clearly observed from this brief study. It is concluded that inter-layer thickness has the significant role in determining the DS of LGs. The statistical analysis confirmed the strong association of DS with inter-layer thickness and the interlayer type. It was found that the LG-PVB composite has the comparatively lower DS than LG-EVA composite and inter-layer thickness has the prominent role in the determination of DS in the LG-EVAcomposite. There is an increment in DS with an increment in critical inter-layer thickness in both LG-EVA and LG-PVBcomposites. The increment in the inter-layer thickness from 0.38 mm to 0.76 mm increases DS significantly; whereas, the further increment in the inter-layer thickness to the higher value has a lesser effect. The finite element model was constituted(without considering the effect of temperature) for determining DS of LG composite. The simulation results were in a good match with experimental results. The results of the present work can be utilized by the design engineers while selecting LG for structural applications.