Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 30

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Evaluation of local damage to reinforced concrete panels subjected to oblique impact by soft missile

Nishida, Akemi; Kang, Z.; Nagai, Minoru*; Tsubota, Haruji; Li, Y.

Nuclear Engineering and Design, 350, p.116 - 127, 2019/08

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete structures caused by impacts of rigid missiles. Most of these formulas have been derived based on tests involving impact normal to target structures. Thus far, few tests with oblique impact onto target structures have been carried out. As a final goal of this research, we aim to propose a new formula for evaluating the local damage caused by oblique impact based on previous experimental and simulation results. In this study, we perform simulation analyses for evaluating the local damage to reinforced concrete panels subjected to oblique impacts with various angle by soft missiles under various impact velocities using a simulation method that was validated using the results of previous impact experiments. In this paper, the investigated results and obtained knowledges from them are shown.

Journal Articles

Impact assessment on local damage to reinforced concrete panels by different projectiles; Impact behavior for projectiles with hemispherical nose shape

Kang, Z.; Nagai, Minoru*; Nishida, Akemi; Tsubota, Haruji; Li, Y.

Proceedings of 25th International Conference on Structural Mechanics in Reactor Technology (SMiRT-25) (USB Flash Drive), 10 Pages, 2019/08

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete (RC) structures caused by rigid projectile impact. The majority of these formulae aim at impact tests perpendicular to target structures, while few impact tests oblique to the target structure have been studied. The final objective of this study is to propose a new formula for evaluating the local damage to RC structures caused by oblique impact based on past experimental and simulation results. Up to now, we validated the analytical method by comparison with the experimental results and conduct the simulation analysis of impact assessment on RC panel by rigid/soft projectile with flat nose shape using the validated approach. In the part 1 of this paper, the same analytical method is used to simulate the local damage to RC panels caused by oblique impact of rigid/soft projectile with hemispherical nose shape. The results associated with penetration depth of RC structure, energy contribution ratio, etc. are presented.

Journal Articles

Simulation analysis on local damage to reinforced concrete panels subjected to oblique impact by different projectiles, 1; Comparison of impact behavior for rigid projectiles with flat and hemispherical nose shape

Kang, Z.; Nagai, Minoru*; Nishida, Akemi; Tsubota, Haruji; Li, Y.

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 9 Pages, 2019/05

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete (RC) structures caused by rigid projectile impact. The majority of these formulae aim at impact tests perpendicular to target structures, while few impact tests oblique to the target structure have been studied. The final objective of this study is to propose a new formula for evaluating the local damage to RC structures caused by oblique impact based on past experimental and simulation results. The finite element code LS-DYNA R7.1.2 is used to perform the numerical analysis by adopting Lagrangian finite elements and explicit time integration. So far, we validated the analytical method by comparison with the experimental results and conduct the simulation analysis of impact assessment on RC panel by rigid/soft projectile with flat nose shape using the validated approach. Results of reduction coefficient with respect to rigid/soft projectile and impact angle were obtained. Therefore, in this study, we focus on the impact problems caused by rigid projectile with hemispherical nose shape. The same analytical method is used to simulate the local damage to RC panels caused by oblique impact of rigid projectile with hemispherical nose shape. The results associated with penetration depth of RC structure, energy contribution ratio, etc. are presented. According to the comparison analysis of results of local damage to RC structure by rigid projectiles with flat and hemispherical nose shape, the influence of different nose shapes of rigid projectile on the local damage of RC panels caused by oblique impact is investigated.

Journal Articles

Simulation analysis on local damage to reinforced concrete panels subjected to oblique impact by different projectiles, 2; Comparison of impact behavior for soft projectiles with flat and hemispherical nose shape

Nagai, Minoru*; Kang, Z.; Nishida, Akemi; Tsubota, Haruji; Li, Y.

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

In this study, the final purpose is to propose a new formula for evaluating the local damage caused by oblique impact based on past experimental results and previous research achievements. Up to now, we validated the analytical method by comparison with the experimental results and conducted simulation analysis associated with impact assessment on RC panel by soft/rigid projectile with flat nose shape using the validated approach. In the part 1 of this study, the same procedure of our previous work is followed to investigate the local damage to RC panel caused by rigid projectile with flat and hemispherical nose shape. In the part 2, we focus on the comparison analysis of simulation results of local damage to RC panel subjected to oblique impact by soft missile with flat and hemispherical nose shape. The structural damage of RC panel and projectiles, energy contribution ratio, etc. is studied for each case. The results indicate the difference of nose shape of projectile is of great importance to influence the penetration depth generated by oblique impact of soft projectile.

Journal Articles

Evaluation of local damage to reinforced concrete panels subjected to oblique impact; Simulation analysis for evaluating perforation phenomena caused by oblique impact of deformable projectiles

Nishida, Akemi; Nagai, Minoru*; Tsubota, Haruji; Li, Y.

Mechanical Engineering Journal (Internet), 5(5), p.18-00087_1 - 18-00087_21, 2018/08

To date, oblique impact has not been studied and few experimental data on the local damage of reinforced concrete (RC) panels exist for oblique impact of deformable projectiles. The final purpose of this study is to propose a new formula for evaluating the local damage to reinforced concrete structures caused by oblique impact based on past experimental results and simulation results. As the first step of this final purpose, we validate the analytical method by comparison with the experimental results and simulate the damage caused by oblique impact using the validated method. First, we analyze and simulate the local damage of RC panel caused by a deformable projectile owing to an impact test normal to the target structure to verify the validity of the simulation analysis. Next, we perform simulation analyses for evaluating the perforation of RC panel due to oblique impact by the deformable projectile and present the results. Various response characteristics and perforation mechanisms to be the basis of examination of oblique impact evaluation were clarified in this paper.

Journal Articles

Evaluation of local damage to reinforced concrete panels subjected to oblique impact of rigid and soft missiles

Nishida, Akemi; Nagai, Minoru*; Tsubota, Haruji; Li, Y.

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete (RC) structures caused by impacts of rigid missiles. Most of these formulas have been derived based on impact tests normal to the target structures. Up to now, few impact tests oblique to the target structures have been carried out. This study has been conducted with the purpose of proposing a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. In this paper, the results of simulation analyses for evaluating the local damage to a RC panel subjected to normal and oblique impacts by rigid and soft missiles, by using the simulation method that was validated using the results of previous impact experiments. Based on the results of these simulation analyses, the effects of the rigidity of the missile as well as the impact angle on the local damage to the target structures are clarified.

Journal Articles

Evaluation of local damage to reinforced concrete panels subjected to oblique impact of soft missile

Nishida, Akemi; Ota, Yoshimi*; Tsubota, Haruji; Li, Y.

Transactions of 24th International Conference on Structural Mechanics in Reactor Technology (SMiRT-24) (USB Flash Drive), 10 Pages, 2017/08

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete structures caused by impacts of rigid missiles. Most of these formulas have been derived based on tests involving impact perpendicular to target structures. Thus far, few tests with oblique impact onto target structures have been carried out. In this study, we aim to propose a new formula for evaluating the local damage caused by oblique impact based on previous experimental and simulation results. We performed simulation analyses for evaluating the local damage to reinforced concrete panels subjected to oblique impacts by soft missiles under various impact velocities by using a simulation method that was validated using the results of previous impact experiments. Based on the results of these simulation analyses, quantitative evaluation of the reduction in local damage and the differences in energy transfer process due to the difference in impact angle and impact velocity are investigated.

Journal Articles

A Study for evaluating local damage to reinforced concrete panels subjected to oblique impact of deformable projectile

Nishida, Akemi; Ota, Yoshimi*; Tsubota, Haruji; Li, Y.

Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 10 Pages, 2017/07

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete (RC) structures caused by impacts of rigid projectiles. Most of these formulas have been derived based on impact tests perpendicular to the target structures. Up to now, few impact tests oblique to the target structures have been carried out. This study has been conducted with the purpose of proposing a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. In this paper, the results of simulation analyses for evaluating the local damage to a RC panel subjected to normal and oblique impacts by deformable projectile, by using the simulation method that the validity was confirmed through simulation analysis of past impact experimental results. Based on the results of these simulation analyses, the quantitative evaluation of reduction effects in the local damage caused by the difference of the impact angle is investigated.

Journal Articles

A Study for evaluating local damage to RC panels subjected to oblique impact, 1; A Study for evaluating local damage caused by oblique impact of rigid projectiles

Ota, Yoshimi*; Nishida, Akemi; Tsubota, Haruji; Li, Y.

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 6 Pages, 2017/07

Many empirical formulae have been proposed to evaluate the local damage to reinforced concrete structures caused by the impact of rigid projectiles. Most of these formulae have been derived based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. The purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impacts based on experiments and simulations. The new formula is derived by modifying an empirical formulation for normal impact and the agreement with results of past oblique impact tests is discussed.

Journal Articles

A Study for evaluating local damage to reinforced concrete panels subjected to oblique impact, 2; Simulation analysis of the experimental results of local damage caused by impact of deformable projectiles

Nishida, Akemi; Ota, Yoshimi*; Tsubota, Haruji; Li, Y.

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 8 Pages, 2017/07

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid projectile impact. Most of these formulae are based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. In this study, we aim to obtain a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. We analyze and simulate the local damage owing to impact by deformable projectiles. The experimental and simulation results were in good agreement and confirmed the validity of the proposed analytical method. Furthermore, the internal energy of the deformable projectile absorbed upon impact was approximately 60% of the total energy. In comparison to a rigid projectile, it is possible to reduce the impact load and consequently the damage to the target.

Journal Articles

A Study for evaluating local damage to reinforced concrete panels subjected to oblique impact, 3; Simulation analysis for evaluating perforation phenomena caused by oblique impact of deformable projectiles

Tsubota, Haruji; Ota, Yoshimi*; Nishida, Akemi; Li, Y.

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 7 Pages, 2017/07

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid projectile impact. Most of these formulae have been derived based on impact tests perpendicular to target structures. To date, few impact tests oblique to target structures have been carried out. Therefore, in this study, we propose a new formula for evaluating the local damage caused by oblique impact based on past experimental results and the results of simulation analyses. In this paper, we present the results of simulation analyses for evaluating the local damage to reinforced concrete panels caused by normal and oblique impact of deformable projectiles, focusing especially on perforation phenomena. Based on the analytical results, we investigate the differences in impact response characteristics between normal and oblique impact.

Journal Articles

Criteria for performance evaluation and numerical verification to shock-resistant design of buildings

Nishida, Akemi; Mukai, Yoichi*; Hamamoto, Takuji*; Kushibe, Atsumichi*; Komuro, Masato*; Ohashi, Yasuhiro*; Obi, Hirotoshi*; Tsubota, Haruji

Proceedings of 12th International Conference on Shock and Impact Loads on Structures (SI 2017) (USB Flash Drive), p.379 - 388, 2017/06

Some design examples are presented to evaluate the shock-resistant performance of target buildings to confirm the applicability of the design criteria of AIJ guideline. Dynamic analyses are performed using SDOF model of an individual member on which an impulsive load is acting. Furthermore, analyses are performed using finite element model for the same member, and the results are compared to the results of the corresponding SDOF model for validation. Frame building structure model which is supposed to be located at the corner of a crossroad is investigated as an example. Dynamic responses and the corresponding damage states are illustrated for this building subjected to shock loads due to road vehicle crashes. As a non-structure member case, examples of window glass destruction subjected to internal and external gas explosions are presented.

Journal Articles

A Study for evaluating surface crater depth to structures subjected to oblique impact

Ota, Yoshimi*; Nishida, Akemi; Tsubota, Haruji

Kozo Kogaku Rombunshu, A, 63A, p.1132 - 1140, 2017/03

Many empirical formulas have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid missile impact. Most of these formulas have been derived based on impact tests perpendicular to target structures and up to now few impact tests oblique to target structures has been carried out. Therefore, the purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impact based on past experimental results and simulation results. In this paper, a new formula is derived by modifying a past empirical formula of normal impact and the conformity of the formula to the results of past oblique impact tests is discussed.

Oral presentation

A Study for evaluating local damage to structures subjected to oblique impact

Ota, Yoshimi*; Nishida, Akemi; Tsubota, Haruji

no journal, , 

Many empirical formulas have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid missile impact. Most of these formulas have been derived based on impact tests perpendicular to target structures and up to now few impact tests oblique to target structures has been carried out. Therefore, the purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impact based on past experimental results. A new formula is derived by modifying a past empirical formula of normal impact and the conformity of the formula to the results of past oblique impact tests is discussed.

30 (Records 1-20 displayed on this page)