연구논문 수정 번역(한국어 원본)2. In page 2, the definition and explanation of variables are needed in more detail.
: page 2의 내용을 상세히 설명하기 위하여 equivalent stiffness matrix(Keq)와 관련된 수식을 추가하였으며 설명을 보충하였습니다. 3. Eq (10) needs the reference or the derivation
: 기존의 식 (8) ~ (12)는 reduced equivalent stiffness matrix를 구하는 과정에 대한 상세한 설명입니다. 이 방법은 많은 연구들에서 이미 활용되고 설명되고 있는 이론이며 이를 본 논문에서 온전히 설명하기 보다는 관련된 참고문헌을 추가하는 것이 합리적이라고 판단하였습니다. 이에 식 (8) ~ 식(12)를 삭제하고 page 2의 수식들을 수정하면서 관련 문헌을 추가하였습니다. 추가된 참고문헌은 다음과 같습니다.
Cook, R. D., Malkus, D. S., Plesha, M. E., and Witt, R. J., “Concepts and Applications of Finite Element Analysis,” 4th edition, 2002.
Gupta, P., Giridhara, G. and Gopalakrishnan, S., “Damage Detection Based on Damage Force Indicator Using Reduced-Order FE Models”, Int. J. Comput. Method. Eng. Sci. Mech., Vol. 9, No. 3, pp. 154-170. 4. In mild sheet modeling, thickness is 3mm in page 3. I wonder that 3mm means total thickness of two sheets or 1 sheet thickness. It is obscure in this paper.
: mild sheet 한 개의 thickness가 3 mm 입니다. 명확한 이해를 위하여 Fig. 2에 치수를 기입하였습니다. 5. Contact resistance calculation is very important factor to simulate spot welding. Author used the Ref. 11 to calculate it. However, Ref. 11 is for the aluminum alloy welding. Could it be applied to mild steel? It should be considered in text.
-> 저자의 실수로 잘 못된 참고 문헌을 적었습니다. 지적해 주신 오류를 수정하기 위하여 올바른 참고문헌을 추가하였습니다. 수정된 참고문헌은 다음과 같습니다.
Feng, Z., Gould, J. E., Babu, S. S. and Santella, M. L., “An Incrementally Coupled Electrical-Thermal-Mechanical Model for Resistance Spot Welding,” Proceedings of the 5th International Conference on Trends in welding research, pp. 599-604, 1999. 6. In Fig. 3, the mark of welding time, hold time and cooling time should be inserted. It makes reader easier to understand the paper.
: 지적해 주신 내용을 반영하기 위하여 Fig.3 에 welding time 및 hold time을 표시하였습니다. 또한 본문에 time을 적었습니다. 7. In page 3, 2nd column, 32th line, “there was some error due to differences in the thickness of the sheets” is written. But it is not understandable. It needs more explanation. If the thickness of the sheets for simulation is different, it should be changed with the same thickness results. Comparison with different thickness result could not be proper.
: 본문에 명확한 설명을 하지 않아 혼동을 일으킨 점 죄송합니다. 참고문헌은 US단위계를 사용하였으며 본 논문의 경우 SI단위계를 사용하였습니다. 참고문헌의 sheet thickness 는 0.12 in (3.048 mm) 본 연구의 sheet thickness는 3.0 mm 입니다. 두 모델의 차이는 이러한 치수 차이에서 발생하였습니다. 두 모델의 치수 및 해석결과차이는 미미하다고 판단되며 이에 혼동을 방지하기 위하여 해당 문구를 삭제하였습니다. 삭제된 문구는 다음과 같습니다.
‘but there was some error due to differences in the thickness of the sheets.’ 8. In Fig. 4, the nugget of weld shows too small in my opinion. Is it proper welding condition? I think that it needs verification by experiment. In addition, some boundary conditions such as material and mechanical properties of mild sheet, cooling water condition and so on should be inserted.
: 온도가 1500℃ 이상인 영역은 nugget 영역을 모사하기 위하여 윗면과 아래면의 sheet의 DOF를 coupling 시켰습니다. 그림에서 두 sheet가 벌어지지 않는 영역의 radius은 약 4mm 정도입니다. 또한 이는 spot welding process에서 일반적으로 나타나는 치수 입니다(Vural et al, 2006; Mohd, 2008; Tsai et al, 1991; Martinson et al, 2009; Okan, 2003). 최종적인 nugget 영역과 HAZ를 효과적으로 설명하기 위하여 Fig. 4에 다음의 그림을 추가하였습니다. 그림에서 붉은 영역은 1500 C 이상의 nugget 부분이며 파란색은 HAZ입니다. 또한 copper electrode와 mild steel의 시간에 관한 다양한 material property를 Table .1 로 정리하여 본문에 삽입하였습니다. 추가된 Table. 1은 다음과 같습니다.
9. The relationship between Chap. 3 and Chap. 4 should be explained in the text. Author just set the nugget radius as 4 mm. It also needs explanation of “Why choose the nugget radius as 4mm”.
: 3장에서 1500℃ 이상 올라간 영역의 radius은 대략 4mm 입니다. 이를 반영하여 Chap. 4의 nugget radius는 4 mm 로 산정하였습니다. 명확한 이해를 위하여 4.3에 이 내용을 언급하였습니다. 10. Author compared some models in Table 1 and the results shows the Table 2 and 3. In order to get the accuracy of model, I wonder that simulation should be compared with experiment instead of comparing between simulation models.
: Model 3, 4, 5는 Xu et al, (2004)이 제안한 simplified finite element 모델입니다. 이 중 rigid model인 model 5, 6 이 welding으로 인한 경화 현상을 모사하는데 더욱 적합한 것으로 알려져 있으며 본 연구에서 제안한 equivalent stiffness matrix model(model 1)은 이와 유사한 거동을 보입니다. 또한 model 1은 model 5, 6 보다는 약한 stiffness를 보이며 이는 rigid body로 표현된 model 5, 6과 달리 경화된 material propertiy가 반영된 stiffness를 이용하여 보다 실질적인 용접부 nugget을 표현할 수 있다고 판단 됩니다. 명확한 이해를 위하여 각 model들의 참고문헌 표시를 명확하게 수정하였습니다. 부가적으로 본 연구실은 butt welding, fillet welding 등 arc welding process에서 finite element model을 생성하는 연구를 다년간 수행해왔습니다. 특히 자동차회사 및 다른 연구기관과의 공동연구를 통해 전용 모델 생성, equivalent stiffness matrix model 등을 제안하고 이에 대한 실험을 병행하여 해당 process에 대한 검증을 마쳤습니다. 그러나 기업의 기밀유지로 인하여 이와 관련된 내용을 논문에 포함하지 못하는 실정입니다. 본 연구에서는 기존에 검증하였던 welding finite element modeling process를 spot welding 에 적용하였으며 이 방법이 spot welding에도 적용이 가능할 것으로 예상하고 있습니다. 그러나 관련된 실험데이터를 얻거나 참고하기 어려워 다른 연구자들을 통해 제안된 spot welding model과 비교하였습니다. 앞서 언급한 바와 같이 본 연구진이 제안한 방법에 관련된 검증 내용을 본문에 포함할 수는 없으나 필요한 경우 관련보고서 등을 참고할 수 있도록 보내드릴 수 있습니다. |
연구논문 수정 번역(영어 번역본)2. In page 2, the definition and explanation of variables are needed in more detail.
: To provide a detailed description of the contents of page 2, the authors added a equation related to the equivalent stiffness matrix (Keq), and supplemented the description. 3. Eq (10) needs the reference or the derivation
: Existing equations (8) ~ (12) are detailed description of the process of obtaining the reduced equivalent stiffness matrix. This method is a theory that is already utilized and described by many researches, and the authors thought that it is more reasonable to add related references than fully explaining it in this paper. Accordingly, equations (8) ~ (12) were deleted and related references were added while the equations in page 2 were modified. The added references are as follows:
Cook, R. D., Malkus, D. S., Plesha, M. E., and Witt, R. J., “Concepts and Applications of Finite Element Analysis,” 4th edition, 2002.
Gupta, P., Giridhara, G. and Gopalakrishnan, S., “Damage Detection Based on Damage Force Indicator Using Reduced-Order FE Models”, Int. J. Comput. Method. Eng. Sci. Mech., Vol. 9, No. 3, pp. 154-170. 4. In mild sheet modeling, thickness is 3mm in page 3. I wonder that 3mm means total thickness of two sheets or 1 sheet thickness. It is obscure in this paper.
: The thickness of one mild sheet is 3 mm. For clear understanding, dimensions were provided in Fig. 2. 5. Contact resistance calculation is very important factor to simulate spot welding. Author used the Ref. 11 to calculate it. However, Ref. 11 is for the aluminum alloy welding. Could it be applied to mild steel? It should be considered in text.
-> The authors provided a wrong reference by mistake. To correct the errors you pointed out, the authors added the correct reference as below:
Feng, Z., Gould, J. E., Babu, S. S. and Santella, M. L., “An Incrementally Coupled Electrical-Thermal-Mechanical Model for Resistance Spot Welding,” Proceedings of the 5th International Conference on Trends in welding research, pp. 599-604, 1999. 6. In Fig. 3, the mark of welding time, hold time and cooling time should be inserted. It makes reader easier to understand the paper.
: To reflect what you pointed out, the welding time and hold time were inserted in Fig.3. Also, the time was recorded in the text of this paper. 7. In page 3, 2nd column, 32nd line, “there was some error due to differences in the thickness of the sheets” is written. But it is not understandable. It needs more explanation. If the thickness of the sheets for simulation is different, it should be changed with the same thickness results. Comparison with different thickness result could not be proper.
: The authors are sorry to have caused confusion as they did not provide clear explanation. The US unit system is used in the references, and this paper used the SI unit system. The sheer thickness of the references was 0.12 in (3.048 mm), whereas the sheet thickness of this study is 3.0 mm. The differences between the two models were caused by the differences in dimensions. The differences between the two models in terms of dimensions and analysis are negligible, and to prevent confusion, the related phrase was deleted. The deleted phrase is shown below:
‘but there was some error due to differences in the thickness of the sheets.’ 8. In Fig. 4, the nugget of weld shows too small in my opinion. Is it proper welding condition? I think that it needs verification by experiment. In addition, some boundary conditions such as material and mechanical properties of mild sheet, cooling water condition and so on should be inserted.
: In areas where the temperature is 1500℃ or higher, to simulate the nugget area, the DOFs on the top surface and the bottom surface were coupled. The radius of the area where there is no gap between the sheets in the figure is about 4mm. Also, this size is ordinary in the spot welding process (Vural et al, 2006; Mohd, 2008; Tsai et al, 1991; Martinson et al, 2009; Okan, 2003). To effectively explain the final nugget area and HAZ, the following drawing was added to Fig. 4. The red area in the figure is the nugget hotter than 1500 ℃, and the blue area is HAZ. Also, various material properties concerning the time of the copper electrode and mild steel were summarized in Table 1, which is inserted in the text of this paper. The added Table 1 is as follows: 9. The relationship between Chap. 3 and Chap. 4 should be explained in the text. Author just set the nugget radius as 4 mm. It also needs explanation of “Why choose the nugget radius as 4mm”.
: The radius of the area, which became hotter than 1500℃ in Chapter 3, is approximately 4mm. It was reflected, and the nugget radius in Chap. 4 was 4 mm. For clear understanding, it was mentioned in Subheading 4.3. 10. Author compared some models in Table 1 and the results shows the Table 2 and 3. In order to get the accuracy of model, I wonder that simulation should be compared with experiment instead of comparing between simulation models.
: Models 3, 4 and 5 are the simplified finite model proposed by Xu et al. (2004). The rigid models among them, i.e. models 5 and 6 are known to be more suitable for simulating the hardening due to welding, and the equivalent stiffness matrix model (model 1) proposed in this study shows a similar behavior. Also, the stiffness of model 1 is less than that of models 5 and 6, and unlike models 5 and 6, expressed as rigid bodies, model 1 can use stiffness, reflecting hardened material properties, to express a more realistic nugget of weld. For clear understanding, the references for each model were clearly modified. In addition, this laboratory has been conducting researches on generating finite element models in the arc welding processes, such as butt welding and fillet welding, for many years. In particular, it conducted joint researches with car makers and other research institutions to generate dedicated models and propose equivalent stiffness matrix models, and verified the processes by conducting experiments at the same time. Due to confidentiality agreements with corporations, however, such contents cannot be included in this paper. In this study, the welding finite element modeling process, which was previously verified, was applied to spot welding, and it is expected that it will be possible to apply this method to spot welding. As it is difficult to obtain or refer to related experimental data, however, comparison was made with the sport welding model proposed by researchers. As mentioned previously, the verification of the method proposed by the authors cannot be included in the text of this paper, but if necessary, the authors can send you related reports for your reference. |
