Faculty Profiles - NODA, Toshihiro

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Performance assessment of soils and structures by numerical analysis Invited International conference

Noda, T.

ISSMGE Virtual University 2021.12.1 International Society for Soil Mechanics and Geotechnical Engineering

Proposal of a super/subloading friction model describing state change of contact surface and the importance of loading criterion with plastic multiplier expressed by displacement rate

2024.9.3

Event date： 2024.9

Language：Japanese Presentation type：Oral presentation (general)

Country：Japan

In this manuscript, we introduce an elastic-plastic friction model based on the super/subloading surface concept as an extension of the subloading surface friction model by Ozaki and Hashiguchi. In the proposed model, a state in which the static friction coefficient is greater than the kinetic friction coefficient is regarded as a "bulky" state of structure, and the change in the friction coefficient between the static and kinetic frictions at the contact surface is described as the evolution rule of structure. In this paper, the condition imposed on the material constants to ensure the positive definiteness of the denominator of the plastic multiplier has been derived and the importance of the loading criterion based on the numerator of the plastic multiplier represented in terms of the relative displacement rate has been mentioned.

u-w-p formulationに基づく間隙水の浸透を伴って伝わる”圧密波” の一次元伝播解析

豊田智大、野田利弘、松本雅紀

第67回理論応用力学講演会 2024.9.3 日本工学会理論応用力学コンソーシアム

The effects of ground permeability and uplift rate on normal faults formation by elastoplastic finite deformation computation

2024.7.23

Soil-water-air coupled elastoplastic finite deformation simulation of Atami embankment failure considering hydrological survey result

2024.7.23

Derivation of theoretical solutions for wave-induced behavior of elastic seabed under perfectly drained and undrained conditions

2024.7.24

Superiority of u-w-p formulation in seismic response analysis of sandy ground – embankment system with drain

2024.7.24

Centrifuge model tests and numerical analysis of a monopile subjected to lateral cyclic loading in saturated sand

2024.7.24

一次元質点～バネ系を用いた時間依存性上下負荷面摩擦モデルの表現能力の検証

野田利弘、安池亮、豊田智大

第59回地盤工学研究発表会 2024.7.23 公益社団法人地盤工学会

Event date： 2024.7

Language：Japanese Presentation type：Oral presentation (general)

Venue：北海道旭川市 Country：Japan

構造物と地盤の相互作用問題を扱う数値解析においては，境界面での摩擦現象は極度に単純化してモデル化されることが多い．例えば，二物体間は常に固着されていて相対変位速度を生じない（完全固着条件），境界面での摩擦力は一定で変化することはない（完全塑性すべり条件）などの理想化である．しかし，摩擦現象では，接触面の相対変位に伴う固着～すべり状態および静止摩擦力～動摩擦力の滑らかな遷移が予想される．剛塑性的なCoulombの摩擦則ではその滑らかな増減を表現することができないため，これまで著者らは，摩擦力の連続的変化を記述可能なOzaki et al.の時間依存性下負荷面摩擦モデルにAsaoka et al.の上負荷面概念を導入した時間依存性上下負荷面摩擦モデルを提案してきた．静止摩擦係数より動摩擦係数の方が大きい状態を摩擦係数の「嵩張り」と捉え，それが接触面の「構造」に由来するとすることで摩擦係数の変化に物理的意味を与えたモデルとなっている．本稿では，同モデルの表現能力検証にあたり，法線応力の時間的な減少／増加が固着～すべり状態（stick-slip現象）の挙動に与える影響を評価する．

Application of super/subloading surface friction model to initial and boundary value problem and analysis of slip propagation in simple shear field

2024.7.23

3D-FEM simulation of centrifugal model test of well type vacuum consolidation method

2024.7.23

Soil-water coupled finite deformation analysis on a soft ground with risk of large long-term settlement due to embankment loading

2024.7.23

Soft ground characteristics of Kaizu area, which is dominated by highly-structured clay distributed in the alluvium of Nobi Plain

2024.7.23

Numerical simulation on water absorption failure of unsaturated silt triaxial specimens considering coupling of trapped air and continuous air

2024.7.25

繰返し載荷中の液状化程度がその後の非排水繰返しせん断挙動に与える影響

中井健太郎、南龍之介、三宅優香、野田利弘

第59回地盤工学研究発表会 2024.7.24 公益社団法人地盤工学会

Proposal of a numerical method defining boundary water pressure as unknown variable for introduction of hydraulically periodic condition

2024.6.10

Event date： 2024.6

Language：Japanese Presentation type：Oral presentation (general)

Country：Japan

A numerical method (u-p-pb formulation) which treats boundary pressures of ground as unknown variables have been proposed for convenience of controlling various boundary conditions including complex boundary pressures or changeable water flow. In this method, conditions on boundary water flows and boundary pressures are incorporated into u-p formulation to obtain the unknown boundary pressures. The method was applied to the hydraulically periodic condition on side boundaries of seabed under ocean wave loading and it could successfully reproduce the hydraulically periodic behavior expressed by theoretical solutions regardless of permeability of ground.

時間依存性・上下負荷面弾塑性摩擦モデルの初期値問題への適用と特性把握

安池亮、豊田智大、野田利弘

第29回計算工学講演会 2024.6.10 計算工学会

Numerical simulation on water absorption failure of unsaturated silt triaxial specimen considering compressibility of trapped air

2024.6.10

Event date： 2024.6

Language：Japanese Presentation type：Oral presentation (general)

Country：Japan

Numerical simulation on water absorption failure test of unsaturated silt triaxial specimen due to suction decrease and pore pressure increase was conducted using a soil skeleton - capillary water - trapped air - continuous air coupled finite deformation analysis code considering inertia force. As a result, it was shown that the behavior of increasing saturation degree during the process of increasing pore pressure after suction decrease can be described by compressing the trapped air. In addition, the result was compared with that of numerical simulation in which inertia force was not taken into account.

Development of a Darcy-Brinkman style w-p implicit finite element analysis method.

2024.6.10

Event date： 2024.6

Language：Japanese Presentation type：Oral presentation (general)

Country：Japan

Darcy and viscous resistances exist as resistance acting on a fluid flow in porous media. The Darcy-Brinkman equation is known as the governing equation for porous flow considering both resistances. In this study, a dynamic w-p analysis method was developed based on the Darcy-Brinkman equation as the governing
equation, expecting the future connection to geomechanics. The method is characterised by (1) implicit time integration scheme, (2) the consideration of fluid viscosity, and (3) spatial discretization by the combination of FEM and FVM. The method was verified for plane-Poiseuille, Couette and Cavity flows.

時間依存性下負荷面摩擦モデルを適用した速度型動的微小変形解析手法の開発

安池亮，豊田智大，野田利弘

土木学会第78回年次学術講演会 2023.9.14 土木学会

Event date： 2023.9

Language：Japanese Presentation type：Oral presentation (general)

Venue：広島大学（東広島キャンパス） Country：Japan

これまで，構造物～地盤の相互作用問題においては，物体間の摩擦について種々の理想化がなされることが多く，接触面が常に完全固着状態あるいは完全塑性すべり状態（摩擦なし，または定摩擦力の作用）で仮定されてきた．しかし，実際の摩擦現象では，固着～すべり状態の滑らかな遷移とそれに応じた静止摩擦力～動摩擦力間での連続的な摩擦力の増減が生じる．そこで本稿では，摩擦力の連続的変化を記述可能な時間依存性下負荷面摩擦モデルを速度型動的微小変形解析手法に境界条件として実装し，安定すべりやstick-slip現象といった摩擦由来の顕著な動的非線形現象が初期値境界値問題の解として得られることを示す．

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