Process modeling of composites by resin transfer molding: practical applications of sensitivity analysis for isothermal considerations

Henz, Brian J.; Tamma, Kumar K.; Kanapady, Ramdev; Ngo, N. D.; Chung, Peter W.

doi:10.1108/09615530310475894

Cited by 9 publications

(8 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sensitivity analysis is a useful design tool, which involves the study of how sensitive the outcome of process is to the variations of given input parameters , ordinarily by taking partial derivative of state variables with respect to the sensitivity parameters:

S_{f} = \frac{\partial f}{\partial p},

where

S_{f}

denotes parameter sensitivity (e.g.,

S_{P}

the pressure sensitivity), and p is the sensitivity parameter.…”

Section: Construction Of Mathematical Modelsmentioning

confidence: 99%

“…The mold filling time and resin flow front shape are of fundamental importance during the resin flow process, so we should investigate the influences of different parameters on the mold filling time and resin flow front shape. In each time step, the volume of fluid injected into the mold cavity is illustrated as :

V_{Δ t_{f}} = \int_{0}^{Δ t_{f}} q_{inlet} d t,

where the subscript 0 denotes the beginning of time step.

q_{inlet}

(m 3 s −1 ) represents the injection flow rate, and

q_{inlet} = A u_{0}

, in which A (m 2 ) is the cross section of porous preform and

u_{0}

(m s −1 ) is the inlet velocity.…”

Section: Construction Of Mathematical Modelsmentioning

confidence: 99%

“…Recently, many researchers have studied the resin infiltration stage during RTM processes, mainly investigating on the influence of processing conditions on composite material properties . In addition, Tamma et al introduced the sensitivity analysis method to compare the sensitive degree of resin filling process to the different parameters . They constructed the sensitivity equations by taking partial derivative of Darcy's equation, and discretized the related governing equations by means of the finite element method.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sensitivity analysis on resin transfer molding processes with edge effect and curing reaction characteristics

Ding

Jia

2014

Polym. Compos.

View full text Add to dashboard Cite

The mold filling time and resin flow front shape are of fundamental importance during resin transfer molding (RTM) processes, because the former influences productivity and the latter affects composites quality. In this article, considering both edge effect and curing reaction characteristics of the resin flow process, the sensitivity analysis method is introduced to investigate the sensitive degree of mold filling time and resin flow front shape to the key material and processing parameters. The function employed to describe the resin flow front shape is defined, and the mathematical relationships of the key physical parameters, such as fluid pressure sensitivity, flow velocity sensitivity, mold filling time sensitivity, and resin flow front shape sensitivity, are established simultaneously. In addition, then the resin infiltration process is simulated by means of a semi‐implicit iterative calculation method and the finite volume method. The simulated results are in agreement with the analytical ones. The results show that under constant injection velocity conditions, both the change in the resin temperature and the alteration of the inlet velocity hardly affect the resin flow front shape, whereas the influence of edge permeability on the resin flow front shape is the greatest. This study is helpful for designing and optimizing RTM processes. POLYM. COMPOS., 36:2008–2016, 2015. © 2014 Society of Plastics Engineer

show abstract

S_{f} = \frac{\partial f}{\partial p},

where

S_{f}

denotes parameter sensitivity (e.g.,

S_{P}

the pressure sensitivity), and p is the sensitivity parameter.…”

Section: Construction Of Mathematical Modelsmentioning

confidence: 99%

V_{Δ t_{f}} = \int_{0}^{Δ t_{f}} q_{inlet} d t,

where the subscript 0 denotes the beginning of time step.

q_{inlet}

(m 3 s −1 ) represents the injection flow rate, and

q_{inlet} = A u_{0}

, in which A (m 2 ) is the cross section of porous preform and

u_{0}

(m s −1 ) is the inlet velocity.…”

Section: Construction Of Mathematical Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sensitivity analysis on resin transfer molding processes with edge effect and curing reaction characteristics

Ding

Jia

2014

Polym. Compos.

View full text Add to dashboard Cite

show abstract

“…There is a variety of engineering applications ranging from oil recovery and soil flows to composites, printing, polymer filling, fuel cells in which the spread of the fluid phase into porous medium occurs (Holman et al, 2002;Henz et al, 2003;Neacsu et al, 2007). These are multi-physics problems that involve momentum, heat and mass transport, where the structure of porous medium and the distribution of fluid phase that spreads into porous medium change, as well as the characteristic length scales (e.g.…”

Section: Introductionmentioning

confidence: 99%

Numerical solution of wetting fluid spread into porous media

Markicevic

Navaz

2009

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

View full text Add to dashboard Cite

Purpose -The purpose of this paper is to develop a general numerical solution for the wetting fluid spread into porous media that can be used in solving of droplet spread into soils, printing applications, fuel cells, composite processing. Design/methodology/approach -A discrete capillary network model based on micro-force balance is numerically implemented and the flow for an arbitrary capillary number can be solved. At the fluid interface, the boundary condition that accounts for the capillary pressure jump is used. Findings -The wetting fluid spread into porous medium starts as a single-phase flow, and after some particular number of the porous medium characteristic length scales, the multi-phase flow pattern occurs. Hence, in the principal flow direction, the phase content (saturation) decreases, and in the lower limit for the capillary number sufficiently small, the saturation should become constant. This qualitative saturation behavior is observed irrespective of the flow dimensionality, whereas the quantitative results vary for different flow systems.Research limitations/implications -The numerical solution has to be expanded to solve the spread of the fluid in the porous medium after there is no free fluid left at the porous medium surface. Practical implications -It is shown that the multi-phase flow can develop even on a small domain due to the porous medium heterogeneity. Neglecting the medium heterogeneity and flow type can lead to a large error as shown for the droplet spread time in the porous medium. Originality/value -This is believe to be the only paper relating to solving the droplet spread into porous medium as a multi-phase flow problem.

show abstract

“…Solution of the sensitivity equations for transient flow of non-Newtonian fluids is presented by Ilinca et al [36]. Application of CSE to liquid composite molding is reported by Henz et al [37,38]. This paper presents a detailed flow and sensitivity analysis for a generalized Newtonian fluid flowing inside a T -shaped geometry.…”

Section: Introductionmentioning

confidence: 99%

Finite element and sensitivity analysis of thermally induced flow instabilities

Giguère

Ilinca

Pelletier

2010

Numerical Methods in Fluids

View full text Add to dashboard Cite

This paper presents a finite element algorithm for the simulation of thermo‐hydrodynamic instabilities causing manufacturing defects in injection molding of plastic and metal powder. Mold‐filling parameters determine the flow pattern during filling, which in turn influences the quality of the final part. Insufficiently, well‐controlled operating conditions may generate inhomogeneities, empty spaces or unusable parts. An understanding of the flow behavior will enable manufacturers to reduce or even eliminate defects and improve their competitiveness. This work presents a rigorous study using numerical simulation and sensitivity analysis. The problem is modeled by the Navier–Stokes equations, the energy equation and a generalized Newtonian viscosity model. The solution algorithm is applied to a simple flow in a symmetrical gate geometry. This problem exhibits both symmetrical and non‐symmetrical solutions depending on the values taken by flow parameters. Under particular combinations of operating conditions, the flow was stable and symmetric, while some other combinations leading to large thermally induced viscosity gradients produce unstable and asymmetric flow. Based on the numerical results, a stability chart of the flow was established, identifying the boundaries between regions of stable and unstable flow in terms of the Graetz number (ratio of thermal conduction time to the convection time scale) and B, a dimensionless ratio indicating the sensitivity of viscosity to temperature changes. Sensitivities with respect to flow parameters are then computed using the continuous sensitivity equations method. We demonstrate that sensitivities are able to detect the transition between the stable and unstable flow regimes and correctly indicate how parameters should change in order to increase the stability of the flow. Copyright © 2009 John Wiley & Sons, Ltd.

show abstract

Process modeling of composites by resin transfer molding: practical applications of sensitivity analysis for isothermal considerations

Cited by 9 publications

References 24 publications

Sensitivity analysis on resin transfer molding processes with edge effect and curing reaction characteristics

Sensitivity analysis on resin transfer molding processes with edge effect and curing reaction characteristics

Numerical solution of wetting fluid spread into porous media

Finite element and sensitivity analysis of thermally induced flow instabilities

Contact Info

Product

Resources

About