Earticle

범죄현장에 존재하는 족적은 현장, 용의자, 피해자 사이의 연결 고리를 증명하는 매우 중요한 증거이다. 이에 본 실험에서는 캔버스 화 밑창에 조각칼과 압정을 사용하여 각각 2~3 ㎜ 길이와 3 ㎜ 깊이의 인위적인 손상을 가하고 피험자 10명이 2달 동안 신발을 착용한 후 점진적 마모의 형태와 점진적 마모에 의해 생성되는 새로운 패턴, 인위적으로 새긴 손상패턴의 변화에 대해 살펴보았다. 시간이 경과함에 따라 눈에 띄게 마모가 나타나는 곳은 발의 볼 부분과 뒤꿈치 부분이었다. 또한 신발의 특정 구역의 대조족적 상에서 중점적으로 새롭게 트레드 패턴이 생성되는 것을 확인하였다. 인위적으로 새긴 손상패턴은 점진적 마모에 의해 없어지거나 생성되는 시기와 위치가 사람마다 다른 것을 관찰 할 수 있었다. 따라서 현장에서 수집한 족적과 시간이 지난 후 수집한 용의자 신발의 대조족적을 비교할 때 서로 다른 신발이라고 해석 할 수 있으므로 판단에 신중을 기하여야한다.

Footwear impression which is one of the typical impression evidence can be linked to a crime scene, a suspect, and a victim. Artificial cut marks, 2~3 ㎜ length made by a graver and 3 ㎜ depth made by a thumb tack, were cut into CCTAS outsoles of 10 pairs of shoes. The present study is an attempt to observe loss and change of the artificial cut marks and acquisition of new tread pattern on two-dimentional test impression during 2 months period. Results indicate that wear patterns appear more frequently in the heel areas and beneath the metatarsal area of the feet. Also, new tread patterns on two-dimentional impression in the specific areas of outsoles can be observed due to progressive wear. The section and time of disappearance and appearance of artificial characteristics differ from individual to individual due to progressive wear. Results suggest that the footwear examiner should pay more attention before giving a judgment, because the progressive changes appeared at the time of evidence collection can be varied depending on the usage conditions.

The force and moment simulation of a steady-state rolling tire taking the effect of tread pattern into account is described using a steady-state transport method with ABAQUS. Tread meshes can not fully consider a tread pattern because detailed tread meshes are not allowed in the steady-state transport method. Therefore, the tread elements are modeled to have orthotropic property instead of isotropic property. The force and moment simulation has been carried out for the cases of both isotropic and orthotropic properties of tread elements. Both cases of simulation results are then compared with the experimental results. It is verified that the orthotropic case is in a better agreement with the experimental result than the isotropic case. Angle effects of tread pattern have been studied by changing the orientation angle of orthotropic property of tread. It is shown that the groove angle in the tread shoulder region has a more effect on force and moment of a tire than that in the tread center region.

A tire tread pattern recognition scheme of which the pattern recognition algorithm is designed based on the fuzzy hierarchical clustering method is proposed and compared with the scheme based on the conventional FCM. The features are extracted from the binary images of the tire tread patterns. In the proposed scheme, the protoypes are obtained more easily and schematically than obtained prototypes using FCM. The experimental results of classification for the practical situations are given and shows the usefulness of the proposed scheme.

Texture is one of the important characteristics that has been used to identify objects or regions of interest in an image. Tire tread patterns can be considered as a kind of texture, and these are classified with a texture analysis method. In this sense, this paper proposes a new algorithm for the classification of tire tread pattern. For the classification, cooccurrence matrix for the binary image is used. The performances are tested by experimentally 8 different tire tread pattern and the robustness is examined by including some kinds on noise.

The temperature distribution of steady state rolling tires with detailed tread blocks is numerically predicted using the three dimensional full patterned tire model. A three dimensional periodic patterned tire model is constructed by copying 1-sector mesh in the circumferential direction. Using the static tire contact analysis, the strain cycles during one revolution are approximated with the strains at Guassian points of the elements which are sector-wise repeated within the same circular ring of elements, by neglecting the tire rolling effect. Based upon the multi-axial fatigue theory, the maximum principal strain is used to represent the combined effect of six strain components on the hysteretic loss. In the following, the deformation due to the inflation and vertical load is calculated using ABAQUS. Then heat generation rate in each element is calculated using an in-house code. Lastly, temperature distribution is calculated using ABAQUS again. Through the numerical experiments, the validity of the proposed prediction method is examined by comparing with the experiment and the temperature distribution of a patterned tire model is compared with those of the main-grooved simple tire model.

As the silence of vehicle is more important, noise reduction of tire is more required. Noise of tire is divided into structure home noise and air borne noise. Tire tread has the property such as Hardness. Pattern Noise is caused by changing of tread hardness. This property has influence on the mechanisms which are Block Impact & Stick-slip sound. In the study, we found that the effect of Hardness is related to more Stick-Slip than Impact.