# Shock Absorption Characteristics and Optimal Design of Corrugated Fiberboard Using Drop Testing
## 1 Introduction  
Buffer packaging is essential for ensuring high-quality logistics services. Although the packaging is part of external quality costs, achieving an effective packaging design is essential in the industry [1, 2]. Foamed plastics are commonly used as buffer packaging materials. However, with the rise of environmental awareness, some countries have regulated the use of foamed plastic materials [3]. Recently, corrugated board has been favored for buffer packaging [4, 5, 6, 7]. [PERSON] [6] proposed a numerical model to evaluate the stiffness parameters of corrugated boards; the model was used for the parametric investigation of the influence of local parameters on corrugated board panel stiffness. The results showed that the stiffness parameters were weakly controlled, acting on the fluting shape and composition. Further, design methods for corrugated board containers were reviewed, and two numerical models were developed using finite elements to evaluate the buckling and ultimate load predictions [7]. In practice, the six-step method of cushion packaging design and MIL-HDBK-304C form the most important basis for packaging design [8]. Product damage during delivery may occur from shock (accidental drop during handling) and vibration (bumps during transportation). Therefore, shock absorption and vibration transfer characteristics must be considered in packaging design. The dynamic buffer curve can reveal the shock ab-sorption characteristics of the buffer material. This curve shows the impact strength (maximum acceleration) of a specific buffer material with a specific thickness and height under different static stresses. The dynamic buffering curve can be used to determine the thickness and area of the buffering material in the early design stage. However, because the corrugated board is a composite made of multilayer Kraft paper and corrugated core paper, each layer may be changed owing to cost, leading to various permutations and combinations. Inaddition, the existing buffer material evaluation method to obtain dynamic buffer curve does not provide the final packaging solution and, thus, causes excessive packaging. The dynamic buffer curve is usually U-shaped (Figure 1). Zone A refers to the weight of the heavy hammer being relatively light. When an impact is applied to the cushioning material, the impact force fails to deform the cushioning material but generates a high acceleration. Zone B refers to the heavier weight of the heavy hammer. The cushioning material is deformed upon the application of the impact, prolonging the impact time and greatly reducing the acceleration. Zone B is the most suitable area for cushion design. Zone C refers to the fact that the heavy hammer is too heavy to bear the impact, and a cushion bottom out occurs when the hammer falls. Currently, the cushion material has no buffering effect. A dynamic cushion curve can be used to determine the thickness and area of the cushioning material to avoid cost increases or product damage caused by excessive or insufficient packaging. However, this curve is obtained by the ASTM D1596 [9] test under a specific combination of buffer material type, thickness, and drop height and can only be used to describe the shock absorption characteristics of the buffer material under that specific combination. When conditions change, time-consuming experiments must be repeated to obtain the curve. Thus far, Taiwanese buffer material manufacturers have not provided dynamic buffer curve data, although they have been widely used in other countries. The cost of test equipment is high, and only large institutions such as the Industrial Research Institute have such equipment. Generally, the industry or design units do not have such equipment, and obtaining the required information by self-testing is challenging. Since a series of tests have to be performed, it is costly and time-consuming for small- and medium-sized enterprises (SMEs) to obtain the required dynamic buffer curve data.