The study found that there is no clear trend in the difference of the ECT values between these standards as a function of the basis weight of the corrugating medium. The ECT value measured by T 839 was much less than the ECT measured by other standards when the basis weight of  
Figure 1: Orthotropic properties of corrugated board components (fiber orientation) and corrugated paperboard (flute direction). the corrugating medium was small. However, it was much higher than the ECT measured by others when the basis weight of the corrugating medium was large. The study concluded that the clamping pressure and out-of-plane flat crush resistance in T 839 affected the results. The conditions to produce an acceptable ECT value can be summarized into four points: (a) Measure what is intended to measure, i.e., pure compression strength of the whole corrugated test specimen, (b) accurate and (c) reproducible, and (d) easy to perform as a routine method in a corrugated paperboard laboratory [6; 21]. Experimental methods for investigating the performance and properties of the corrugated paperboard and corrugated paperboard-based products have limitations from time and economic perspectives. In addition, it is impossible to quantitatively analyze the effect of each component of the corrugated paperboard on ECT. Therefore, computer simulation techniques like finite element analysis (FEA) recently have been used to analyze various characteristics including ECT of corrugated paperboard [1; 2; 3; 7; 10; 22; 23]. Most FEA studies have focused on analyzing mechanisms of buckling, failure, stability, and adherence strength of corrugated paperboard [1; 2; 3; 24; 25] and investigating compression and flexural behavior of different flute types [10]. Some FEA studies have also tried to optimize board combinations of corrugated paperboard, to analyze performance and strength of corrugated paperboard boxes, and to develop FEA simulations to replace the conventional semi-empirical equations [22; 26; 27]. Since paper has a complex mechanical behavior representing orthotropic material properties and high non-linearity, specific material models and advanced FE techniques have been required for analyzing paper-based products like the corrugated paperboard. Therefore, some researchers [7; 23; 24; 28] conducted studies to investigate equivalent stiffness properties to develop simplified FE models for corrugated paperboard. [PERSON] and [PERSON] [22] conducted FEA for ECT specimens cut based on the recommendations of EFCO No.8 testing standard. They found that frictional contact conditions between the modeled test specimen and the rigid surface did not significantly affect the ECT value for A/F (A-flute) and C/F (C-flute) (difference due to the frictional contact condition was less than 3%). However, there was an approximately 15% difference in B/F depending on the frictional contact condition. [PERSON] et al. [29] analyzed the effect of the Young's modulus of its components on the overall Young's modulus of C/F corrugated paperboard using an analytical method. They found that liners affected much more mechanical strength of the corrugated paperboard than corrugating mediums since the gradient of Young's modulus between the liners and corrugated paperboard was approximately 88 times higher than the gradient of the Young's modulus between the corrugating medium and corrugated paperboard. The FEA has been successfully used to predict the mechanical properties of the corrugated paperboard; however, a study analyzing the various test methods of ECT is rare.