Assessment of Composite Damage Growth Tools for Aircraft Structure Part II

Author(s):  
Stephen P. Engelstad ◽  
Stephen Clay
Author(s):  
Stephen P. Engelstad ◽  
Jason Action ◽  
Stephen B. Clay ◽  
Richard Holzwarth ◽  
Richard W. Dalgarno ◽  
...  

2016 ◽  
Vol 51 (10) ◽  
pp. 1325-1331 ◽  
Author(s):  
Stephen B Clay ◽  
Stephen P Engelstad

This article introduces an Air Force Research Laboratory study, which performed static and fatigue benchmark exercises for nine composite progressive damage analysis methods. Air Force Research Laboratory is interested in exploring the feasibility of these progressive damage analysis methods to predict composite damage growth for the purposes of improved durability and damage tolerance analysis of composite aircraft structure. This article gives the background, goals, motivation, and guiding principles of the study and provides brief descriptions of the teams that participated and the tools that were utilized.


2016 ◽  
Vol 51 (10) ◽  
pp. 1493-1524 ◽  
Author(s):  
Stephen P Engelstad ◽  
Stephen B Clay

This paper provides overall comparisons of the static results of an Air Force Research Laboratory exploration into the state of the art of existing technology in composite progressive damage analysis. In this study, blind and re-calibration bench-marking exercises were performed using nine different composite progressive damage analysis codes on unnotched and notched (open-hole) composite coupons under both static and fatigue loading. This paper summarizes the results of the static portion of this program. Comparisons are made herein of specimen stiffness and strength predictions against each other and the test data. Overall percent error data is presented, as well as a list of observations and lessons learned during this year-long effort.


2017 ◽  
Vol 51 (15) ◽  
pp. 2227-2249 ◽  
Author(s):  
SP Engelstad ◽  
SB Clay

This paper provides overall comparisons of the fatigue results of an Air Force Research Laboratory exploration into the state of the art of existing technology in composite progressive damage analysis. This program performed blind and recalibration benchmarking exercises for nine different composite progressive damage analysis codes using unnotched and open-hole composite coupons under both static and fatigue loading. This paper summarizes the results of the fatigue portion of this program in which seven of the codes were evaluated. Comparisons are made herein for all seven participants’ predictions with the test data. Overall percent error data are presented, as well as a long list of observations and lessons learned during this year-long effort.


2021 ◽  
Vol 11 (11) ◽  
pp. 4743
Author(s):  
Fernando Cepero-Mejias ◽  
Nicolas Duboust ◽  
Vaibhav A. Phadnis ◽  
Kevin Kerrigan ◽  
Jose L. Curiel-Sosa

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45∘ and 90∘ manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.


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