Numerical Modeling of Stacked Composite CFRP/Ti Machining under Different Cutting Sequence Strategies

Jinyang Xu,Mohamed El Mansori 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.1

Stacked composite CFRP/Ti is identified as an innovative structural configuration for manufacturing the key aircraft components favoring energy saving in the modern aerospace industry. Machining of this composite-to-metal alliance exhibits the most challenging task in manufacturing community due to the disparate natures of each phase involved and their respective poor machinability. Since the experimental studies are highly cost and time consuming, the numerical approach should be a capable alternative to overcoming the several technical limitations involved. In this research, an original FE model was developed to simulate the complete chip formation process when orthogonal cutting (OC) of hybrid CFRP/Ti stacks. Different constitutive models and failure criteria were implemented into the Abaqus/Explicit code to construct the entire machining behavior of the stacked composite material. The stack model was built to replicate accurately the key physical phenomena activated in the hybrid cutting operation. Special concentration was made on the comparative studies of the effects of different cutting-sequence strategies on the machining responses induced by CFRP/Ti cutting. The numerical results highlighted the significant role of cutting-sequence strategy in affecting the final machined surface morphology and subsurface damage extent, and hence emphasized the importance of selecting reasonable cutting-sequence strategy for hybrid CFRP/Ti machining.

Drilling Machinability Evaluation on New Developed High-strength T800S/250F CFRP Laminates

Jinyang Xu,Ming Chen,Qinglong An,Xiaojiang Cai 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

The new developed high-strength CFRP laminates are widely employed in varieties of applications and are mainly used in main loadbearing structural components of large commercial aircrafts. Drilling is one of the important operations in manufacturing composite structure, often a final operation during assembly. Defects such as burrs and delamination in drilling of CFRP are always serious problems and lead to rejection and impose heavy loss. In the present research, the machinability of a new developed high-strength T800S/250F CFRP laminate is evaluated by using CVD coated twist drill and CVD coated dagger drill. The machinability was investigated in terms of drilling forces, burr defect, hole wall surface morphology and delamination damage. The results indicate that feed rate is the most significant factor affecting the machined surface finish followed by the spindle speed. The dagger drill showed excellent drilling performance than the twist drill and was more suitable for drilling of T800S/250F CFRP laminate. The results also highlight the importance of employing the high speed drilling to minimize the drilling-induced defects.

Cutting Modeling Using Cohesive Zone Concept of Titanium/CFRP Composite Stacks

Jinyang Xu,Mohamed El Mansori 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In modern aerospace industry, hybrid CFRP/Ti stacks have taken a prominent position in manufacturing aircraft and spacecraft structural components due to their combined resistance and enhanced characteristics favoring the energy saving. Compared to the great interest of experimental studies, nearly rare scientific literature deals with the numerical modeling of hybrid CFRP/Ti cutting. This is the key incentive that motivates the current research to propose an original FE model to address the mentioned issues. The FE model was developed into Abaqus/Explicit commercial code. The CFRP phase was modeled as an equivalent homogeneous material (EHM) by implementing Hashin damage criteria to simulate the rupture and separation of the fiber/matrix system. The Ti phase was assumed isotropic with elastoplastic behavior, and Johnson-Cook criteria were utilized to replicate the local failure of the metallic phase. The CFRP/Ti interface physically described as an intermediate constituent was modeled through the concept of cohesive zone (CZ). The multiple aspects of machining responses induced in hybrid CFRP/Ti cutting were precisely investigated with a special focus on the interface damage formation. The numerical results highlighted the significant effects of feed rate on the force generation and the pivotal role of bi-material interface consumption (BIC) in affecting the interface delamination.

Insight into Fundamental Rules of Phenylenediamines Selective Monoacylation by the Comparisons of Kinetic Characteristics in Microreactor

Xu Qilin,Liu Ji Ming,Yao Hongmiao,Zhao Jinyang,Wang Zhikuo,Liu Junli,Zhou Jiadi,Yu Zhiqun,Su Weike 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.10

In this paper, the kinetics of acylation reaction of o-phenylenediamine/p-phenylenediamine and benzoic anhydride were determined in microreactors, respectively. A kinetic model was established, all kinetic parameters including reaction orders, reaction rate constants, pre-exponential factors, and activation energies were acquired. Validation experiments showed experimental data fit well with calculated data at different reactant concentrations and residence times. The comparisons of the reaction rate constants and activation energies were summarized to show the difference of chemical reactivities of phenylenediamines. According to the calculation of the kinetic model, the optimized reaction conditions were listed to meet the monoacylation selectivity equal to 97.0%.

A Coupling Method of Response Surfaces (CRSM) for Cutting Parameters Optimization in Machining Titanium Alloy under Minimum Quantity Lubrication (MQL) Condition

Zhiqiang Liu,Ming Chen,Jinyang Xu,Shu Han 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

This paper presents a new flexible method referring to coupling response surface methodology (CRSM) to acquire optimum cutting parameters in machining of difficult-to-cut titanium alloy under minimum quantity lubrication (MQL) condition. Cutting speed, feed rate and depth of cut are designed as three factors by using the Taguchi method, which are also subject to several constraints including processing efficiency, cutting force and surface quality. In addition, turning experiments of titanium alloy were performed in order to set up the model based on Taguchi experimental design and multiple regression method. ANOVA was carried out to prove the adequacy of the developed mathematical model and the influences of cutting parameters on constraints were also observed. The results indicated that the feed rate was the dominant factor affecting surface roughness and cutting forces, which were minimized when the feed rate and depth of cut were set to the lowest level, while cutting speed was set to the highest level. Moreover, the predicted values obtained by CRSM were in good agreement with the experimental values, which indicated that CRSM was an effective method to determine optimum cutting conditions for machining process under MQL condition.

Equilibrium, kinetic and mechanism studies on the biosorption of Cu2+ and Ni2+ by sulfur-modified bamboo powder

Tian Ai,Xiaojun Jiang,Hongmei Yu,Hong-Bo Xu,Dawei Pan,Qingyu Liu,Dongyu Chen,Jinyang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Two biosorbents were prepared using bamboo powder modified with mercaptoacetic acid and carbondisulfide, which exhibits strong adsorption properties for Cu2+ and Ni2+. The obtained materials were characterized byFTIR. Maximum adsorption for both metals was found to occur around pH 5.0-6.5. The kinetic data followed thepseudo-second-order model. The maximum adsorption capacities of Cu2+ and Ni2+ on mercaptoacetic acid modifiedbamboo powder determined from Langmuir isotherm were 103.97mg g−1 and 61.35mg g−1, respectively. While oncarbon disulfide modified bamboo powder were 128.21mg g−1 and 56.82mg g−1, respectively. The adsorption mechanismanalysis revealed that the most possible adsorption mode of Cu2+ was coordination, and Ni2+ was ion exchange. The obtained adsorbents could effectively remove Cu2+ and Ni2+ from industrial electroplating wastewater and could beused repeatedly for more than five cycles.