Citation: Stefano Almi, Giuliano Lazzaroni, Ilaria Lucardesi. Crack growth by vanishing viscosity in planar elasticity[J]. Mathematics in Engineering, 2020, 2(1): 141-173. doi: 10.3934/mine.2020008
[1] | Juan H. Arredondo, Genaro Montaño, Francisco J. Mendoza . A new characterization of the dual space of the HK-integrable functions. AIMS Mathematics, 2024, 9(4): 8250-8261. doi: 10.3934/math.2024401 |
[2] | Mukhamed Aleroev, Hedi Aleroeva, Temirkhan Aleroev . Proof of the completeness of the system of eigenfunctions for one boundary-value problem for the fractional differential equation. AIMS Mathematics, 2019, 4(3): 714-720. doi: 10.3934/math.2019.3.714 |
[3] | Imran Talib, Md. Nur Alam, Dumitru Baleanu, Danish Zaidi, Ammarah Marriyam . A new integral operational matrix with applications to multi-order fractional differential equations. AIMS Mathematics, 2021, 6(8): 8742-8771. doi: 10.3934/math.2021508 |
[4] | Erdal Bas, Ramazan Ozarslan . Theory of discrete fractional Sturm–Liouville equations and visual results. AIMS Mathematics, 2019, 4(3): 593-612. doi: 10.3934/math.2019.3.593 |
[5] | Ahmed M.A. El-Sayed, Eman M.A. Hamdallah, Hameda M. A. Alama . Multiple solutions of a Sturm-Liouville boundary value problem of nonlinear differential inclusion with nonlocal integral conditions. AIMS Mathematics, 2022, 7(6): 11150-11164. doi: 10.3934/math.2022624 |
[6] | Jiaye Lin . Evaluations of some Euler-type series via powers of the arcsin function. AIMS Mathematics, 2025, 10(4): 8116-8130. doi: 10.3934/math.2025372 |
[7] | Tuba Gulsen, Sertac Goktas, Thabet Abdeljawad, Yusuf Gurefe . Sturm-Liouville problem in multiplicative fractional calculus. AIMS Mathematics, 2024, 9(8): 22794-22812. doi: 10.3934/math.20241109 |
[8] | Anwar Ahmad, Dumitru Baleanu . On two backward problems with Dzherbashian-Nersesian operator. AIMS Mathematics, 2023, 8(1): 887-904. doi: 10.3934/math.2023043 |
[9] | Juya Cui, Ben Gao . Symmetry analysis of an acid-mediated cancer invasion model. AIMS Mathematics, 2022, 7(9): 16949-16961. doi: 10.3934/math.2022930 |
[10] | M. Mossa Al-Sawalha, Khalil Hadi Hakami, Mohammad Alqudah, Qasem M. Tawhari, Hussain Gissy . Novel Laplace-integrated least square methods for solving the fractional nonlinear damped Burgers' equation. AIMS Mathematics, 2025, 10(3): 7099-7126. doi: 10.3934/math.2025324 |
When studying various applied problems related to the properties of media with a periodic structure, it is necessary to study differential equations with rapidly changing coefficients. Equations of this type are often found, for example, in electrical systems under the influence of high frequency external forces. The presence of such forces creates serious problems for the numerical integration of the corresponding differential equations. Therefore, asymptotic methods are usually applied to such equations, the most famous of which are the Feshchenko – Shkil – Nikolenko splitting method [9,10,11,12,23] and the Lomov's regularization method [18,20,21]. The splitting method is especially effective when applied to homogeneous equations, and in the case of inhomogeneous differential equations, the Lomov regularization method turned out to be the most effective. However, both of these methods were developed mainly for singularly perturbed equations that do not contain an integral operator. The transition from differential equations to integro-differential equations requires a significant restructuring of the algorithm of the regularization method. The integral term generates new types of singularities in solutions that differ from the previously known ones, which complicates the development of the algorithm for the regularization method. The splitting method, as far as we know, has not been applied to integro-differential equations. In this article, the Lomov's regularization method [1,2,3,4,5,6,7,8,13,14,15,16,17,19,24] is generalized to previously unexplored classes of integro-differential equations with rapidly oscillating coefficients and rapidly decreasing kernels of the form
Lεz(t,ε)≡εdzdt−A(t)z−εg(t)cosβ(t)εB(t)z−∫tt0e1ε∫tsμ(θ)dθK(t,s)z(s,ε)ds=h(t),z(t0,ε)=z0,t∈[t0,T], | (1.1) |
where z={z1,z2},h(t)={h1(t),h2(t)},μ(t)<0(∀t∈[t0,T]), g(t) is the scalar function, A(t) and B(t) are (2×2)-matrices, moreover A(t)=(01−ω2(t)0), ω(t)>0,β′(t)>0 is the frequency of the rapidly oscillating cosine, z0={z01,z02},ε>0 is a small parameter. It is precisely such a system in the case β(t)=2γ(t),B(t)=(0010) and in the absence of an integral term was considered in [18,20,21].
The functions λ1(t)=−iω(t), λ2(t)=+iω(t) form the spectrum of the limit operator A(t), the function λ5(t)=μ(t) characterizes the rapid change in the kernel of the integral operator, and the functions λ3(t)=−iβ′(t), λ4(t)=+iβ′(t) are associated with the presence of a rapidly oscillating cosine in the system (1.1). The set {Λ}={λ1(t),...,λ5(t)} is called the spectrum of problem (1.1). Such systems have not been considered earlier and in this paper we will try to generalize the Lomov's regularization method [18] to systems of type (1.1).
We introduce the following notations:
λ(t)=(λ1(t),...,λ5(t)),
m=(m1,...,m5) is a multi-index with non-negative components mj,j=¯1,5,
|m|=∑5j=1mj is the height of multi-index m,
(m,λ(t))=∑5j=1mjλj(t).
The problem (1.1) will be considered under the following conditions:
1)ω(t),μ(t),β(t)∈C∞([t0,T],R),ω(t)≠β′(t)∀t∈[t0,T],
g(t)∈([t0,T],C1),h(t)∈C∞([t0,T],C2),
B(t)∈C∞([t0,T],C2×2),K(t,s)∈C∞({t0≤s≤t≤T},C2×2);
2) the relations (m,λ(t))=0,(m,λ(t))=λj(t),j∈{1,...,5} for all multi-indices m with |m|≥2 or are not fulfilled for any t∈[t0,T], or are fulfilled identically on the whole segment [t0,T]. In other words, resonant multi-indices are exhausted by the following sets:
Γ0={m:(m,λ(t))≡0,|m|≥2,∀t∈[t0,T]},Γj={m:(m,λ(t))≡λj(t),|m|≥2,∀t∈[t0,T]},j=¯1,5. |
Note that by virtue of the condition ω(t)≠β′(t), the spectrum {Λ} of the problem (1.1) is simple.
Denote by σj=σj(ε) independent on t the quantities σ1=e−iεβ(t0), σ2=e+iεβ(t0) and rewrite the system (1.1) in the form
Lεz(t,ε)≡εdzdt−A(t)z−εg(t)2(e−iε∫tt0β′(θ)dθσ1+e+iε∫tt0β′(θ)dθσ2)B(t)z−∫tt0e1ε∫tsμ(θ)dθK(t,s)z(s,ε)ds=h(t),z(t0,ε)=z0,t∈[t0,T]. | (2.1) |
We introduce regularizing variables (see [18])
τj=1ε∫tt0λj(θ)dθ≡ψj(t)ε,j=¯1,5 | (2.2) |
and instead of the problem (2.1) we consider the problem
Lε˜z(t,τ,ε)≡ε∂˜z∂t+5∑j=1λj(t)∂˜z∂τj−A(t)˜z−εg(t)2(eτ3σ1+eτ4σ2)B(t)˜z |
−∫tt0e1ε∫tsμ(θ)dθK(t,s)˜z(s,ψ(s)ε,ε)ds=h(t),˜z(t,τ,ε)|t=t0,τ=0=z0,t∈[t0,T] | (2.3) |
for the function ˜z=˜z(t,τ,ε), where it is indicated (according to (2.2)): τ=(τ1,...,τ5),ψ=(ψ1,...,ψ5). It is clear that if ˜z=˜z(t,τ,ε) is the solution of the problem (2.3), then the vector function z=˜z(t,ψ(t)ε,ε) is the exact solution of the problem (2.1), therefore, the problem (2.3) is expansion of the problem (2.1). However, it cannot be considered completely regularized, since the integral term
J˜z≡J(˜z(t,τ,ε)|t=s,τ=ψ(s)/ε)=∫tt0e1ε∫tsμ(θ)dθK(t,s)˜z(s,ψ(s)ε,ε)ds |
has not been regularized in (2.3).
To regularize the integral term, we introduce a class Mε, asymptotically invariant with respect to the operator J˜z (see [18], p. 62]). We first consider the space of vector functions z(t,τ), representable by sums
z(t,τ,σ)=z0(t,σ)+∑5i=1zi(t,σ)eτi+∑∗2≤|m|≤Nzzm(t,σ)e(m,τ),z0(t,σ),zi(t,σ),zm(t,σ)∈C∞([t0,T],C2),i=¯1,5,2≤|m|≤Nz, | (2.4) |
where the asterisk ∗ above the sum sign indicates that in it the summation for |m|≥2 occurs only over nonresonant multi-indices m=(m1,...,m5), i.e. over m∉⋃5i=0Γi. Note that in (2.4) the degree of the polynomial with respect to exponentials eτj depends on the element z. In addition, the elements of the space U depend on bounded in ε>0 constants σ1=σ1(ε) and σ2=σ2(ε), which do not affect the development of the algorithm described below, therefore, henceforth, in the notation of element (2.4) of this space U, we omit the dependence on σ=(σ1,σ2) for brevity. We show that the class Mε=U|τ=ψ(t)/ε is asymptotically invariant with respect to the operator J.
The image of the operator J on the element (2.4) of the space U has the form:
Jz(t,τ)=∫tt0e1ε∫tsλ5(θ)dθK(t,s)z0(s)ds+5∑i=1∫tt0e1ε∫tsλ5(θ)dθK(t,s)zi(s)e1ε∫st0λi(θ)dθds |
+∗∑2≤|m|≤Nz∫tt0e1ε∫tsλ5(θ)dθK(t,s)zm(s)e1ε∫st0(m,λ(θ))dθds |
=∫tt0e1ε∫tsλ5(θ)dθK(t,s)z0(s)ds+e1ε∫tt0λ5(θ)dθ∫tt0K(t,s)z5(s)ds |
+5∑i=1,i≠5e1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zi(s)e1ε∫st0(λi(θ)−λ5(θ))dθds |
+∗∑2≤|m|≤Nze1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zm(s)e1ε∫st0(m−e5,λ(θ))dθds. |
Integrating in parts, we have
J0(t,ε)=∫tt0K(t,s)z0(s)e1ε∫tsλ5(θ)dθds=ε∫tt0K(t,s)z0(s)−λ5(s)de1ε∫tsλ5(θ)dθ |
=εK(t,s)z0(s)−λ5(s)e1ε∫tsλ5(θ)dθ|s=ts=t0−ε∫tt0(∂∂sK(t,s)z0(s)−λ5(s))e1ε∫tsλ5(θ)dθds |
=ε[K(t,t0)z0(t0)λ5(t0)e1ε∫tt0λ5(θ)dθ−K(t,t)z0(t)λ5(t)]+ε∫tt0(∂∂sK(t,s)z0(s)λ5(s))e1ε∫tsλ5(θ)dθds. |
Continuing this process further, we obtain the decomposition
J0(t,ε)=∞∑ν=0εν+1[(Iν0(K(t,s)z0(s)))s=t0e1ε∫tt0λ5(θ)dθ−(Iν0(K(t,s)z0(s)))s=t],I00=1λ5(s)⋅,Iν0=1λ5(s)∂∂sIν−10(ν≥1). |
Next, apply the same operation to the integrals:
J5,i(t,ε)=e1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zi(s)e1ε∫st0(λi(θ)−λ5(θ))dθds |
=εe1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zi(s)λi(s)−λ5(s)de1ε∫st0(λi(θ)−λ5(θ))dθ |
=εe1ε∫tt0λ5(θ)dθ[K(t,s)zi(s)λi(s)−λ5(s)e1ε∫st0(λi(θ)−λ5(θ))dθ|s=ts=t0−ε∫tt0(∂∂sK(t,s)zi(s)λi(s)−λ5(s))e1ε∫st0(λi(θ)−λ5(θ))dθds] |
=ε[K(t,t)zi(t)λi(t)−λ5(t)e1ε∫tt0λi(θ)dθ−K(t,t0)zi(t0)λi(t0)−λ5(t0)e1ε∫tt0λ5(θ)dθ] |
−εe1ε∫tt0λ5(θ)dθ∫tt0(∂∂sK(t,s)zi(s)λi(s)−λ5(s))e1ε∫st0(λi(θ)−λ5(θ))dθds |
=∞∑ν=0(−1)νεν+1[(Iνi(K(t,s)zi(s)))s=te1ε∫tt0λi(θ))dθ−(Iνi(K(t,s)zi(s)))s=t0e1ε∫tt0λ5(θ)dθ], |
I0i=1λi(s)−λ5(s),Iνi=1λi(s)−λ5(s)∂∂sIν−1i(ν≥1),i=¯1,4; |
Jm(t,ε)=e1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zm(s)e1ε∫st0(m−e5,λ(θ))dθds |
=εe1ε∫tt0λ5(θ)dθ∫tt0K(t,s)zm(s)(m−e5,λ(s))de1ε∫st0(m−e5,λ(θ))dθ=εe1ε∫tt0λ5(θ)dθ[K(t,s)zm(s)(m−e5,λ(s))e1ε∫st0(m−e5,λ(θ))dθ|s=ts=t0 |
−ε∫tt0(∂∂sK(t,s)zm(s)(m−e5,λ(s)))e1ε∫st0(m−e5,λ(θ))dθds] |
=ε[K(t,t)zm(t)(m−e5,λ(t))e1ε∫tt0(m,λ(θ))dθ−K(t,t0)zm(t0)(m−e5,λ(t0))e1ε∫tt0λ5(θ)dθ] |
−εe1ε∫tt0λ5(θ)dθ∫tt0(∂∂sK(t,s)zm(s)(m−e5,λ(s)))e1ε∫st0(m−e5,λ(θ))dθ |
=∞∑ν=0(−1)νεν+1[(Iν5,m(K(t,s)zm(s)))s=te1ε∫tt0(m,λ(θ))dθ−(Iν5,m(K(t,s)zm(s)))s=t0e1ε∫tt0λ5(θ)dθ], |
I05,m=1(m−e5,λ(s)),Iν5,m=1(m−e5,λ(s))∂∂sIν−15,m(ν≥1),2≤|m|≤Nz. |
Here it is taken into account that (m−e5,λ(s))≠0, since by definition of the space U, multi-indices m∉Γ5. This means that the image of the operator J on the element (2.4) of the space U is represented as a series
Jz(t,τ)=e1ε∫tt0λ5(θ))dθ∫tt0K(t,s)z5(s)ds+∞∑ν=0(−1)νεν+1[(Iν0(K(t,s)z0(s)))s=t0e1ε∫tt0λ5(θ))dθ |
−(Iν0(K(t,s)z0(s)))s=t]+5∑i=1,i≠5∞∑ν=0(−1)νεν+1[(Iνi(K(t,s)zi(s)))s=te1ε∫tt0λi(θ))dθ |
−(Iνi(K(t,s)zi(s)))s=t0e1ε∫tt0λ5(θ)dθ] |
+∗∑2≤|m|≤Nz∞∑ν=0(−1)νεν+1[(Iν5,m(K(t,s)zm(s)))s=te1ε∫tt0(m,λ(θ))dθ−(Iν5,m(K(t,s)zm(s)))s=t0e1ε∫tt0λ5(θ)dθ]. |
It is easy to show (see, for example, [22], pages 291–294) that this series converges asymptotically as ε→+0 (uniformly in t∈[t0,T]). This means that the class Mε is asymptotically invariant (as ε→+0) with respect to the operator J.
We introduce the operators Rν:U→U, acting on each element z(t,τ)∈U of the form (2.4) according to the law:
R0z(t,τ)=eτ5∫tt0K(t,s)z5(s)ds, | (2.50) |
R1z(t,τ)=[(I00(K(t,s)z0(s)))s=t0eτ5−(I00(K(t,s)z0(s)))s=t] |
+4∑i=1[(I0i(K(t,s)zi(s)))s=teτi−(I0i(K(t,s)zi(s)))s=t0eτ5] | (2.51) |
+∗∑2≤|m|≤Nz[(I05,m(K(t,s)zm(s)))s=te(m,τ)−(I05,m(K(t,s)zm(s)))s=t0eτ5], |
Rν+1z(t,τ)=∞∑ν=0(−1)ν[(Iν0(K(t,s)z0(s)))s=t0eτ5−(Iν0(K(t,s)z0(s)))s=t] |
+4∑i=1∞∑ν=0(−1)ν[(Iνi(K(t,s)zi(s)))s=teτi−(Iνi(K(t,s)zi(s)))s=t0eτ5] | (2.5v+1) |
+∗∑2≤|m|≤Nz∞∑ν=0(−1)ν[(Iν5,m(K(t,s)zm(s)))s=te(m,τ)−(Iν5,m(K(t,s)zm(s)))s=t0eτ5]. |
Let now ˜z(t,τ,ε) be an arbitrary continuous function in (t,τ)∈[t0,T]×{τ:Reτj≤0,j=¯1,5} with asymptotic expansion
˜z(t,τ,ε)=∞∑k=0εkzk(t,τ),zk(t,τ)∈U | (2.6) |
converging as ε→+0 (uniformly in (t,τ)∈[t0,T]×{τ:Reτj≤0,j=¯1,5}). Then the image J˜z(t,τ,ε) of this function is decomposed into an asymptotic series
J˜z(t,τ,ε)=∞∑k=0εkJzk(t,τ)=∞∑r=0εrr∑s=0Rr−szs(t,τ)|τ=ψ(t)/ε. |
This equality is the basis for introducing an extension of the operator J on series of the form (2.6):
˜J˜z(t,τ,ε)≡˜J(∞∑k=0εkzk(t,τ))def=∞∑r=0εrr∑s=0Rr−szs(t,τ). | (2.7) |
Although the operator ˜J is formally defined, its usefulness is obvious, since in practice it is usual to construct the N-th approximation of the asymptotic solution of the problem (2.1), in which only N-th partial sums of the series (2.6) will take part, which have not formal, but true meaning. Now we can write down a problem that is completely regularized with respect to the original problem (2.1):
Lε˜z(t,τ,ε)≡ε∂˜z∂t+∑5j=1λj(t)∂˜z∂τj−A(t)˜z−εg(t)2(eτ3σ1+eτ4σ2)B˜z−−˜J˜z=h(t),˜z(t,τ,ε)|t=t0,τ=0=z0,t∈[t0,T], | (2.8) |
were the operator ˜J has the form (2.7).
Substituting the series (2.6) into (2.8) and equating the coefficients for the same powers of ε, we obtain the following iterative problems:
Lz0(t,τ)≡5∑j=1λj(t)∂z0∂τj−A(t)z0−R0z0=h(t),z0(t0,0)=z0; | (3.10) |
Lz1(t,τ)=−∂z0∂t+g(t)2(eτ3σ1+eτ4σ2)B(t)z0+R1z0,z1(t0,0)=0; | (3.11) |
Lz2(t,τ)=−∂z1∂t+g(t)2(eτ3σ1+eτ4σ2)B(t)z1+R1z1+R2z0,z2(t0,0)=0; | (3.12) |
⋯ |
Lzk(t,τ)=−∂zk−1∂t+g(t)2(eτ3σ1+eτ4σ2)B(t)zk−1+Rkz0+...+R1zk−1,zk(t0,0)=0,k≥1. | (3.1k) |
Each of the iterative problem (3.1k) can be written as
Lz(t,τ)≡5∑j=1λj(t)∂z∂τj−A(t)z−R0z=H(t,τ),z(t0,0)=z∗, | (3.2) |
where H(t,τ)=H0(t)+∑5j=1Hj(t)eτj+∑∗2≤|m|≤NHHm(t)e(m,τ) is a well-known vector-function of the space U, z∗ is a well-known constant vector of a complex space C2, and the operator R0 has the form (see (2.50))
R0z≡R0(z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤Nzzm(t)e(m,τ))=eτ5∫tt0K(t,s)z5(s)ds. |
In the future we need the λj(t)-eigenvectors of the matrix A(t):
φ1(t)=(1−iω(t)),φ2(t)=(1+iω(t)), |
as well as ˉλj(t)-eigenvectors of the matrix A∗(t):
χ1(t)=12(1−iω(t)),χ2(t)=12(1+iω(t)). |
These vectors form a biorthogonal system, i.e.
(φk(t),χj(t))={1,k=j,0,k≠j(k,j=1,2). |
We introduce the scalar product (for each t∈[t0,T]) in the space U:
<z,w>≡<z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤Nzzm(t)e(m,τ),w0(t)+5∑j=1wj(t)eτj |
+∗∑2≤|m|≤Nwwm(t)e(m,τ)>def=(z0(t),w0(t))+5∑j=1(zj(t),wj(t))+∗∑2≤|m|≤min(Nz,Nw)(zm(t),wm(t)), |
where we denote by (∗,∗) the ordinary scalar product in a complex space C2. We prove the following statement.
Theorem 1. Let conditions 1) and 2) are satisfied and the right-hand side H(t,τ)=H0(t)+∑5j=1Hj(t)eτj+∑∗2≤|m|≤NHHm(t)e(m,τ) of the system (3.2) belongs to the space U. Then for the solvability of the system (3.2) in U it is necessary and sufficient that the identities
<H(t,τ),χk(t)eτk>≡0,k=1,2,∀t∈[t0,T], | (3.3) |
are fulfilled.
Proof. We will determine the solution to the system (3.2) in the form of an element (2.4) of the space U:
z(t,τ)=z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤NHzm(t)e(m,τ). | (3.4) |
Substituting (3.4) into the system (3.2), we have
5∑j=1[λj(t)I−A(t)]zj(t)eτj+∗∑2≤|m|≤NH[(m,λ(t))I−A(t)]zm(t)e(m,τ) |
−A(t)z0(t)−eτ5∫tt0K(t,s)z5(s)ds=H0(t)+5∑j=1Hj(t)eτj+∗∑2≤|m|≤NHHm(t)e(m,τ). |
Equating here separately the free terms and coefficients at the same exponents, we obtain the following systems of equations:
−A(t)z0(t)=H0(t), | (3.50) |
[λj(t)I−A(t)]zj(t)=Hj(t),j=¯1,4, | (3.5j) |
[λ5(t)I−A(t)]z5(t)−∫tt0K(t,s)z5(s)ds=H5(t), | (3.55) |
[(m,λ(t))I−A(t)]zm(t)=Hm(t),2≤|m|≤Nz,m∉5⋃j=0Γj. | (3.5m) |
Due to the invertibility of the matrix A(t), the system (3.50) has the solution −A−1(t)H0(t). Since λ5(t)=μ(t) is a real function, and the eigenvalues of the matrix A(t) are purely imaginary, the matrix λ5(t)I−A(t) is invertible and therefore the system (3.55) can be written as
z5(t)=∫tt0([λ5(t)I−A(t)]−1K(t,s))z5(s)ds+[λ5(t)I−A(t)]−1H5(t). | (3.6) |
Due to the smoothness of the kernel ([λ5(t)I−A(t)]−1K(t,s)) and the heterogeneity [λ5(t)I−A(t)]−1H5(t), this Volterra integral system has a unique solution z5(t)∈C∞([t0,T],C2). Systems (3.53) and (3.54) also have unique solutions
zj(t)=[λj(t)I−A(t)]−1Hj(t)∈C∞([t0,T],C2),j=3,4, | (3.7) |
since λ3(t),λ4(t) do not belong to the spectrum of the matrix A(t). Systems (3.51) and (3.52) are solvable in the space C∞([t0,T],C2) if and only if the identities (Hj(t),χj(t))≡0∀t∈[t0,T],j=1,2 hold.
It is easy to see that these identities coincide with the identities (3.3).
Further, since multi-indices m∉⋃5j=0Γj in systems (3.5m), then these systems are uniquely solvable in the space C∞([t0,T],C2) in the form of functions
zm(t)=[(m,λ(t))I−A(t)]−1Hm(t),0≤|m|≤NH. | (3.8) |
Thus, condition (3.3) is necessary and sufficient for the solvability of the system (3.2) in the space U. The theorem 1 is proved.
Remark 1. If identity (3.3) holds, then under conditions 1) and 2) the system (3.2) has (see (3.6) – (3.8)) the following solution in the space U:
z(t,τ)=z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤NHzm(t)e(m,τ)≡z0(t)+2∑k=1αk(t)φk(t)eτk |
+h12(t)φ2(t)eτ1++h21(t)φ1(t)eτ2+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ), | (3.9) |
where αk(t)∈C∞([t0,T],C1) are arbitrary functions, k=1,2,z0(t)=−A−1H0(t),z5(t) is the solution of the integral system (3.6) and the notations are introduced:
h12(t)≡(H1(t),χ2(t))λ1(t)−λ2(t),h21(t)≡(H2(t),χ1(t))λ2(t)−λ1(t),Pj(t)≡[λj(t)I−A(t)]−1Hj(t), |
Pm(t)≡[(m,λ(t))I−A(t)]−1Hm(t). |
We proceed to the description of the conditions for the unique solvability of the system (3.2) in the space U. Along with the problem (3.2), we consider the system
Lw(t,τ)=−∂z∂t+g(t)2(eτ3σ1+eτ4σ2)B(t)z+R1z+Q(t,τ), | (4.1) |
where z=z(t,τ) is the solution (3.9) of the system (3.2), Q(t,τ)∈U is the known function of the space U. The right-hand side of this system:
G(t,τ)≡−∂z∂t+g(t)2(eτ3σ1+eτ4σ2)B(t)z+R1z+Q(t,τ) |
=−∂∂t[z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤NHzm(t)e(m,τ)] |
+g(t)2(eτ3σ1+eτ4σ2)B(t)[z0(t)+5∑j=1zj(t)eτj+∗∑2≤|m|≤NHzm(t)e(m,τ)]+R1z+Q(t,τ), |
may not belong to the space U, if z=z(t,τ)∈U. Since −∂z∂t,R1z,Q(t,τ)∈U, then this fact needs to be checked for the function
Z(t,τ)≡g(t)2(eτ3σ1+eτ4σ2)B(t)[z0(t)+5∑j=1zj(t)eτj |
+∗∑2≤|m|≤NHzm(t)e(m,τ)]=g(t)2B(t)z0(t)(eτ3σ1+eτ4σ2) |
+5∑j=1g(t)2B(t)zj(t)(eτj+τ3σ1+eτj+τ4σ2)+g(t)2(eτ3σ1+eτ4σ2)B(t)∗∑2≤|m|≤NHzm(t)e(m,τ). |
Function Z(t,τ)∉U, since it has resonant exponents
eτ3+τ4=e(m,τ)|m=(0,0,1,1,0),eτ3+(m,τ)(m3+1=m4,m1=m2=m5=0), |
eτ4+(m,τ)(m4+1=m3,m1=m2=m5=0), |
therefore, the right-hand side G(t,τ)=Z(t,τ)−∂z∂t+R1z+Q(t,τ) of the system (19) also does not belong to the space U. Then, according to the well-known theory (see [18], p. 234), it is necessary to embed ∧:G(t,τ)→ˆG(t,τ) the right-hand side G(t,τ) of the system (4.1) in the space U. This operation is defined as follows.
Let the function G(t,τ)=∑N|m|=0wm(t)e(m,τ) contain resonant exponentials, i.e. G(t,τ) has the form
G(t,τ)=w0(t)+5∑j=1wj(t)eτj+5∑j=0N∑|mj|=2:mj∈Γjwmj(t)e(mj,τ)+N∑|m|=2,m≠mj,j=¯0,5wm(t)e(m,τ). |
Then
ˆG(t,τ)=w0(t)+5∑j=1wj(t)eτj+5∑j=0N∑|mj|=2:mj∈Γjwmj(t)eτj+N∑|m|=2,m≠mj,j=¯0,5wm(t)e(m,τ). |
Therefore, the embedding operation acts only on the resonant exponentials and replaces them with a unit or exponents eτj of the first dimension according to the rule:
(e(m,τ)|m∈Γ0)∧=e0=1,(e(m,τ)|m∈Γj)∧=eτj,j=¯1,5. |
We now turn to the proof of the following statement.
Theorem 2. Suppose that conditions 1) and 2) are satisfied and the right-hand side H(t,τ)=H0(t)+∑5j=1Hj(t)eτj+∑∗2≤|m|≤NHHm(t)e(m,τ)∈U of the system (3.2) satisfies condition (3.3). Then the problem (3.2) under additional conditions
<ˆG(t,τ),χk(t)eτk>≡0∀t∈[t0,T],k=1,2, | (4.2) |
where Q(t,τ)=Q0(t)+∑5k=1Qk(t)eτk+∑∗2≤|m|≤NQQm(t)e(m,τ) is the well-known vector function of the space U, is uniquely solvable in U.
Proof. Since the right-hand side of the system (3.2) satisfies condition (3.3), this system has a solution in the space U in the form (3.9), where αk(t)∈C∞([t0,T],C1), k=1,2 are arbitrary functions so far. Subordinate (3.9) to the initial condition z(t0,0)=z∗. We obtain ∑2k=1αk(t0)φk(t0)=z∗, where is indicated
z∗=z∗+A−1(t0)H0(t0)−[λ5(t0)I−A(t0)]−1H5(t0)−4∑j=3[λj(t0)I−A(t0)]−1Hj(t0) |
−(H1(t0),χ2(t0))λ1(t0)−λ2(t0)φ2(t0)−(H2(t0),χ1(t0))λ2(t0)−λ1(t0)φ1(t0)−∗∑2≤|m|≤NHPm(t0). |
Multiplying scalarly the equality ∑2k=1αk(t0)φk(t0)=z∗ by χj(t0) and taking into account the biorthogonality of the systems {φk(t)} and {χj(t)}, we find the values αk(t0)=(z∗,χk(t0)),k=1,2. Now we subordinate the solution (3.9) to the orthogonality condition (4.2). We write in more detail the right-hand side G(t,τ) of the system (4.1):
G(t,τ)≡−∂∂t[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1 |
+h21(t)φ1(t)eτ2+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)] |
+g(t)2(eτ3σ1+eτ4σ2)B(t)[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1 |
+h21(t)φ1(t)eτ2+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)] |
+R1[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2 |
+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)]+Q(t,τ). |
Putting this function into the space U, we will have
ˆG(t,τ)≡−∂∂t[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1 |
+h21(t)φ1(t)eτ2+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)] |
+{g(t)2(eτ3σ1+eτ4σ2)B(t)(z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1 |
+h21(t)φ1(t)eτ2+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)}∧ |
+R1[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2 |
+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)]+Q(t,τ) |
=−∂∂t[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2 |
+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)] (∗∗) |
+{12g(t)B(t)(eτ3σ1z0(t)+eτ3+τ1σ1α1(t)φ1(t)+eτ3+τ2σ1α2(t)φ2(t) |
+eτ3+τ1σ1h12(t)φ2(t)+eτ3+τ2σ1h21(t)φ1(t)+eτ3+τ5σ1z5(t) |
+e2τ3σ1P3(t)+eτ3+τ4σ1P4(t)+eτ4σ2z0(t)+eτ4+τ1σ2α1(t)φ1(t) |
+eτ4+τ2σ2α2(t)φ2(t)+eτ4+τ1σ2h12(t)φ2(t)+eτ4+τ2σ2h21(t)φ1(t) |
+eτ4+τ5σ2z5(t)+eτ3+τ4σ2P3(t)+e2τ4σ2P4(t) |
+12g(t)B(t)∗∑2≤|m|≤NHPm(t)(emτ+τ3σ1+emτ+τ4σ2)}∧ |
+R1[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2 |
+z5(t)eτ5+4∑i=3Pi(t)eτi+∗∑2≤|m|≤NHPm(t)e(m,τ)]+Q(t,τ). |
Given that the expression R1(z0(t,τ)) linearly depends on α1(t) and α2(t) (see the formula (2.51)):
R1(z0(t,τ))≡R1[z0(t)+2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2 |
+z5(t)eτ5+4∑j=3Pj(t)eτj+∗∑2≤|m|≤NHPm(t)e(m,τ)]≡2∑j=1Fj(α1(t),α2(t),t)eτj+˜R1(z0(t,τ)), |
(here Fj(α1(t),α2(t),t) are linear functions of α1(t),α2(t), and the expression ˜R1(z0(t,τ)) does not contain linear terms of α1(t),α2(t)), we conclude that, after the embedding operation, the function ˆG(t,τ) will linearly depend on scalar functions α1(t) and α2(t).
Taking into account that under conditions (4.2), scalar multiplication by vector functions χk(t)eτk, containing only exponentials eτk, k=1,2, it is necessary to keep in the expression ˆG(t,τ) only terms with exponents eτ1 and eτ2. Then it follows from (**) that conditions (4.2) are written in the form
<−∂∂t(2∑k=1αk(t)φk(t)eτk+h12(t)φ2(t)eτ1+h21(t)φ1(t)eτ2) |
+(F1(α1(t),α2(t),t)+∑N|m1|=2:m1∈Γ1wm1(α1(t),α2(t),t))eτ1+(F2(α1(t),α2(t),t)∑N|m2|=2:m2∈Γ2wm2(α1(t),α2(t),t))eτ2 |
+Q1(t)eτ1+Q2(t)eτ2,χk(t)eτk>≡0,∀t∈[t0,T],k=1,2, |
where the functions wmj(α1(t),α2(t),t),j=1,2, depend on α1(t) and α2(t) in a linear way. Performing scalar multiplication here, we obtain linear ordinary differential equations with respect to the functions αk(t),k=1,2, involved in the solution (3.9) of the system (3.2). Attaching the initial conditions αk(t0)=(z∗,χk(t0)), k=1,2, calculated earlier to them, we find uniquely functions αk(t), and, therefore, construct a solution (3.9) to the problem (3.2) in the space U in a unique way. The theorem 2 is proved.
As mentioned above, the right-hand sides of iterative problems (3.1k) (if them solve sequentially) may not belong to the space U. Then, according to [18] (p. 234), the right-hand sides of these problems must be embedded into the U, according to the above rule. As a result, we obtain the following problems:
Lz0(t,τ)≡5∑j=1λj(t)∂z0∂τj−A(t)z0−R0z0=h(t),z0(t0,0)=z0; | (¯3.10) |
Lz1(t,τ)=−∂z0∂t+[g(t)2(eτ3σ1+eτ4σ2)B(t)z0]∧+R1z0,z1(t0,0)=0; | (¯3.11) |
Lz2(t,τ)=−∂z1∂t+[g(t)2(eτ3σ1+eτ4σ2)B(t)z1]∧+R1z1+R2z0,z2(t0,0)=0; | (¯3.12) |
⋯ |
Lzk(t,τ)=−∂zk−1∂t+[g(t)2(eτ3σ1+eτ4σ2)B(t)zk−1]∧+Rkz0+...+R1zk−1,zk(t0,0)=0,k≥1, | (¯3.1k) |
(images of linear operators ∂∂t and Rν do not need to be embedded in the space U, since these operators act from U to U). Such a replacement will not affect the construction of an asymptotic solution to the original problem (1.1) (or its equivalent problem (2.1)), so on the narrowing τ=ψ(t)ε the series of problems (3.1k) will coincide with the series of problems (¯3.1k) (see [18], pp. 234–235].
Applying Theorems 1 and 2 to iterative problems (¯3.1k), we find their solutions uniquely in the space U and construct series (2.6). As in [18] (pp. 63-69), we prove the following statement.
Theorem 3. Let conditions 1)–2) be satisfied for the system (2.1). Then, for ε∈(0,ε0](ε0>0 is sufficiently small) system (2.1) has a unique solution z(t,ε)∈C1([t0,T],C2); at the same time there is the estimate
||z(t,ε)−zεN(t)||C[t0,T]≤cNεN+1,N=0,1,2,..., |
where zεN(t) is the restriction on τ=ψ(t)ε of the N -th partial sum of the series (2.6) (with coefficients zk(t,τ)∈U, satisfying the iterative problems (¯3.1k)) and the constant cN>0 does not depend on ε at ε∈(0,ε0].
Using Theorem 1, we try to find a solution to the first iterative problem (¯3.10). Since the right-hand side h(t) of the system (¯3.10) satisfies condition (3.3), this system (according to (3.9)) has a solution in the space U in the form
z0(t,τ)=z(0)0(t)+2∑k=1α(0)k(t)φk(t)eτk, | (5.1) |
where α(0)k(t)∈C∞([t0,T],C1) are arbitrary functions, k=1,2,z(0)0(t)=−A−1(t)h(t). Subordinating (4.2) to the initial condition z0(t0,0)=z0, we have
2∑k=1α(0)k(t0)φk(t0)=z0+A−1(t0)h(t0). |
Multiplying this equality scalarly χj(t0) and taking into account biorthogonality property of the systems {φk(t)} and {χj(t)}, find the values
α(0)k(t0)=(z0+A−1(t0)h(t0),χk(t0)),k=1,2. | (5.2) |
For a complete calculation of the functions α(0)k(t), we proceed to the next iterative problem (¯3.11). Substituting the solution (5.1) of the system (¯3.10) into it, we arrive at the following system:
Lz1(t,τ)=−ddtz(0)0(t)−2∑k=1ddt(α(0)k(t)φk(t))eτk+K(t,t)z(0)0(t)λ5(t)eτ5−K(t,t0)z(0)0(t0)λ5(t0) |
+[g(t)2(eτ3σ1+eτ4σ2)B(t)(z(0)0(t)+2∑k=1α(0)k(t)φk(t)eτk)]∧ | (5.3) |
+2∑j=1[(K(t,t)α(0)j(t)φj(t))λj(t)eτj−(K(t,t0)α(0)j(t0)φj(t0))λj(t0)], |
(here we used the expression (2.51) for R1z(t,τ) and took into account that when z(t,τ)=z0(t,τ) in the sum (2.51) only terms with eτ1, eτ2 and eτ5 remain). We calculate
M=[g(t)2(eτ3σ1+eτ4σ2)B(t)(z(0)0(t)+2∑k=1α(0)k(t)φk(t)eτk)]∧ |
=12g(t)B(t)[α(0)1σ1φ1(t)eτ3+τ1+σ2α(0)2(t)φ1(t)eτ4+τ1 |
+σ1α(0)2(t)φ2(t)eτ3+τ2+σ2α(0)2(t)φ2(t)eτ4+τ2+eτ3σ1z0(t)+eτ4σ2z0(t))]∧. |
Let us analyze the exponents of the second dimension included here for their resonance:
eτ3+τ1|τ=ψ(t)/ε=e1ε∫tt0(−iβ′−iω)dθ,−iβ′−iω=[0,−iω,+iω,⇔∅,−iβ′−iω=[−iβ′,+iβ′,μ⇔∅; |
eτ4+τ1|τ=ψ(t)/ε=e1ε∫tt0(+iβ′−iω)dθ,+iβ′−iω=[(0),−iω,(+iω),⇔[β′=ω,β′=2ω,+iβ′−iω=[(−iβ′),+iβ′,μ,⇔2β′=ω⇒⇒[^eτ4+τ1=e0=1(β′=ω),^eτ4+τ1=eτ2(β′=2ω),^eτ4+τ1=eτ3(2β′=ω); |
eτ3+τ2|τ=ψ(t)/ε=e1ε∫tt0(−iβ′+iω)dθ,−iβ′+iω=[(0),(−iω),+iω,⇔[β′=ω,β′=2ω;−iβ′+iω=[−iβ′,(+iβ′),μ,⇔2β′=ω⇒[^eτ3+τ2=e0=1(β′=ω),^eτ3+τ2=eτ1(β′=2ω),^eτ3+τ2=eτ4(2β′=ω); |
eτ4+τ2|τ=ψ(t)/ε=e1ε∫tt0(+iβ′+iω)dθ,+iβ′+iω=[0,−iω,+iω,⇔∅,+iβ′+iω=[−iβ′,+iβ′,μ,⇔∅. |
Thus, the exponents eτ3+τ1and eτ4+τ2 are not resonant, and the exponents eτ4+τ1 and eτ3+τ2 are resonant at certain ratios between frequencies β′(t), and ω(t), moreover, their embeddings are carried out as follows:
[^eτ4+τ1=e0=1(β′=ω),^eτ4+τ1=eτ2(β′=2ω),^eτ4+τ1=eτ3(2β′=ω),[^eτ3+τ2=e0=1(β′=ω),^eτ3+τ2=eτ1(β′=2ω),^eτ3+τ2=eτ4(2β′=ω). |
So, resonances are possible only in the following cases of relations between frequencies: a) β′=2ω, b) β′=ω,c) 2β′=ω. Case b) is not considered (see condition (1)). We consider cases a) and c).
a) β′=2ω. In this case, the system (5.3) after embedding takes the form
Lz1(t,τ)=−ddtz(0)0(t)−2∑k=1ddt(α(0)k(t)φk(t))eτk+K(t,t)z(0)0(t)λ5(t)eτ5 |
−K(t,t0)z(0)0(t0)λ5(t0)+12g(t)B(t)[σ1α(0)1(t)φ1(t)eτ3+τ1+σ2α(0)1(t)φ1(t)eτ2 |
+σ1α(0)2(t)φ2(t)eτ1+σ2α(0)2(t)φ2(t)eτ4+τ2+eτ3σ1z0(t)+eτ4σ2z0(t))] |
+2∑j=1[(K(t,t)α(0)j(t)φj(t))λj(t)eτj−(K(t,t0)α(0)j(t0)φj(t0))λj(t0)]. |
This system is solvable in the space U if and only if the conditions of orthogonality are satisfied:
⟨−2∑k=1ddt(α(0)k(t)φk(t))eτk+12g(t)B(t)[σ1α(0)2(t)φ2(t)eτ1 |
+σ2α(0)1(t)φ1(t)eτ2]+2∑i=1(K(t,t)α(0)i(t)φi(t))λi(t)eτi,χj(t)eτj⟩≡0,j=1,2. |
Performing scalar multiplication here, we obtain a system of ordinary differential equations:
−dα(0)1(t)dt−(˙φ1(t),χ1(t))α(0)1(t)+12g(t)σ1(B(t)φ2(t),χ1(t))α(0)2(t)+(K(t,t),χ1(t))λ1(t)α(0)1(t)≡0,−dα(0)2(t)dt−(˙φ2(t),χ2(t))α(0)2(t)++12g(t)σ2(B(t)φ1(t),χ2(t))α(0)1(t)+(K(t,t),χ2(t)(t))λ2(t)α(0)2(t)≡0. | (5.4) |
Adding the initial conditions (5.2) to this system, we find uniquely functions α(0)k(t), k=1,2, and, therefore, uniquely calculate the solution (5.1) of the problem (¯3.10) in the space U. Moreover, the main term of the asymptotic solution of the problem (2.1) has the form
zε0(t)=z(0)0(t)+2∑k=1α(0)k(t)φk(t)e1ε∫tt0λk(θ)dθ, | (5.5) |
where the functions α(0)k(t0) satisfy the problem (5.2), (5.4), z(0)0(t)=−A−1(t)h(t). We draw attention to the fact that the system of equations (5.4) does not decompose into separate differential equations (as was the case in ordinary integro-differential equations). The presence of a rapidly oscillating coefficient in the problem (1.1) leads to more complex differential systems of type (5.4), the solution of which, although they exist on the interval [t0,T], is not always possible to find them explicitly. However, in third case this it manages to be done.
c) 2β′=ω. In this case, the system (5.3) after embedding takes the form (take into account that ^eτ4+τ1=eτ3^,eτ3+τ2=eτ4)
Lz1(t,τ)=−ddtz(0)0(t)−2∑k=1ddt(α(0)k(t)φk(t))eτk+K(t,t)z(0)0(t)λ5(t)eτ5−K(t,t0)z(0)0(t0)λ5(t0) |
+12g(t)B(t)[σ1α(0)1(t)φ1(t)eτ3+τ1+σ2α(0)1(t)φ1(t)eτ2 |
+σ1α(0)2(t)φ2(t)eτ1+σ2α(0)2(t)φ2(t)eτ4+τ2+eτ3σ1z0(t)+eτ4σ2z0(t))] |
+2∑j=1[(K(t,t)α(0)j(t)φj(t))λj(t)eτj−(K(t,t0)α(0)j(t0)φj(t0))λj(t0)]. |
This system is solvable in the space U if and only if the conditions of orthogonality
⟨−2∑k=1ddt(α(0)k(t)φk(t))eτk+2∑i=1(K(t,t)α(0)i(t)φi(t))λi(t)eτi,χj(t)eτj⟩≡0, |
j=1,2, are satisfied. Performing scalar multiplication here, we obtain a system of diverging ordinary differential equations
−dα(0)1(t)dt−(˙φ1(t),χ1(t))α(0)1(t)+(K(t,t),χ1(t))λ1(t)α(0)1(t)≡0,−dα(0)2(t)dt−(˙φ2(t),χ2(t))α(0)2(t)+(K(t,t),χ2(t)(t))λ2(t)α(0)2(t)≡0. |
Together with the initial conditions (5.2), it has a unique solution
α(0)k(t)=(z0+A−1(t0)h(t0),χk(t0))exp{∫tt0(K(θ,θ)−˙φk(θ),χk(θ))λk(θ)dθ}, |
k=1,2, and therefore, the solution (5.1) of the problem (¯3.10) will be found uniquely in the space U. In this case the leading term of the asymptotics has the form (5.5), but with functions α(0)k(t), explicitly calculated. Its influence is revealed when constructing the asymptotics of the first and higher orders.
All authors declare no conflicts of interest in this paper.
[1] |
Almi S (2017) Energy release rate and quasi-static evolution via vanishing viscosity in a fracture model depending on the crack opening. ESAIM Control Optim Calc Var 23: 791-826. doi: 10.1051/cocv/2016014
![]() |
[2] |
Almi S (2018) Quasi-static hydraulic crack growth driven by Darcy's law. Adv Calc Var 11: 161-191. doi: 10.1515/acv-2016-0029
![]() |
[3] |
Almi S, Lucardesi I (2018) Energy release rate and stress intensity factors in planar elasticity in presence of smooth cracks. Nonlinear Differ Equ Appl 25: 43. doi: 10.1007/s00030-018-0536-4
![]() |
[4] | Argatov II, Nazarov SA (2002) Energy release in the kinking of a crack in a plane anisotropic body. Prikl Mat Mekh 66: 502-514. |
[5] |
Babadjian JF, Chambolle A, Lemenant A (2015) Energy release rate for non-smooth cracks in planar elasticity. J Éc polytech Math 2: 117-152. doi: 10.5802/jep.19
![]() |
[6] |
Brokate M, Khludnev A (2004) On crack propagation shapes in elastic bodies. Z Angew Math Phys 55: 318-329. doi: 10.1007/s00033-003-3026-3
![]() |
[7] |
Chambolle A (2003) A density result in two-dimensional linearized elasticity, and applications. Arch Ration Mech Anal 167: 211-233. doi: 10.1007/s00205-002-0240-7
![]() |
[8] |
Chambolle A, Francfort GA, Marigo JJ (2010) Revisiting energy release rates in brittle fracture. J Nonlinear Sci 20: 395-424. doi: 10.1007/s00332-010-9061-2
![]() |
[9] |
Chambolle A, Giacomini A, Ponsiglione M (2008) Crack initiation in brittle materials. Arch Ration Mech Anal 188: 309-349. doi: 10.1007/s00205-007-0080-6
![]() |
[10] |
Chambolle A, Lemenant A (2013) The stress intensity factor for non-smooth fractures in antiplane elasticity. Calc Var Partial Dif 47: 589-610. doi: 10.1007/s00526-012-0529-9
![]() |
[11] |
Costabel M, Dauge M (2002) Crack singularities for general elliptic systems. Math Nachr 235: 29-49. doi: 10.1002/1522-2616(200202)235:1<29::AID-MANA29>3.0.CO;2-6
![]() |
[12] |
Crismale V, Lazzaroni G (2017) Quasistatic crack growth based on viscous approximation: A model with branching and kinking. Nonlinear Differ Equ Appl 24: 7. doi: 10.1007/s00030-016-0426-6
![]() |
[13] |
Dal Maso G, DeSimone A, Solombrino F (2011) Quasistatic evolution for Cam-Clay plasticity: A weak formulation via viscoplastic regularization and time rescaling. Calc Var Partial Dif 40: 125-181. doi: 10.1007/s00526-010-0336-0
![]() |
[14] |
Dal Maso G, DeSimone A, Solombrino F (2012) Quasistatic evolution for Cam-Clay plasticity: Properties of the viscosity solution. Calc Var Partial Dif 44: 495-541. doi: 10.1007/s00526-011-0443-6
![]() |
[15] |
Dal Maso G, Francfort GA, Toader R (2005) Quasistatic crack growth in nonlinear elasticity. Arch Ration Mech Anal 176: 165-225. doi: 10.1007/s00205-004-0351-4
![]() |
[16] |
Dal Maso G, Lazzaroni G (2010) Quasistatic crack growth in finite elasticity with noninterpenetration. Ann Inst H Poincaré Anal Non Linéaire 27: 257-290. doi: 10.1016/j.anihpc.2009.09.006
![]() |
[17] |
Dal Maso G, Morandotti M (2017) A model for the quasistatic growth of cracks with fractional dimension. Nonlinear Anal 154: 43-58. doi: 10.1016/j.na.2016.03.007
![]() |
[18] |
Dal Maso G, Orlando G, Toader R (2015) Laplace equation in a domain with a rectilinear crack: Higher order derivatives of the energy with respect to the crack length. Nonlinear Differ Equ Appl 22: 449-476. doi: 10.1007/s00030-014-0291-0
![]() |
[19] |
Dal Maso G, Toader R (2002) A model for the quasi-static growth of brittle fractures: Existence and approximation results. Arch Ration Mech Anal 162: 101-135. doi: 10.1007/s002050100187
![]() |
[20] | Dauge M (1988) Smoothness and asymptotics of solutions, In: Elliptic Boundary Value Problems on Corner Domains, Berlin: Springer-Verlag. |
[21] |
Destuynder P, Djaoua M (1981) Sur une interprétation mathématique de l'intégrale de Rice en théorie de la rupture fragile. Math Method Appl Sci 3: 70-87. doi: 10.1002/mma.1670030106
![]() |
[22] | Efendiev MA, Mielke A (2006) On the rate-independent limit of systems with dry friction and small viscosity. J Convex Anal 13: 151-167. |
[23] |
Fonseca I, Fusco N, Leoni G, et al. (2007) Equilibrium configurations of epitaxially strained crystalline films: Existence and regularity results. Arch Ration Mech Anal 186: 477-537. doi: 10.1007/s00205-007-0082-4
![]() |
[24] |
Francfort GA, Larsen CJ (2003) Existence and convergence for quasi-static evolution in brittle fracture. Commun Pur Appl Math 56: 1465-1500. doi: 10.1002/cpa.3039
![]() |
[25] |
Francfort GA, Marigo JJ (1998) Revisiting brittle fracture as an energy minimization problem. J Mech Phys Solids 46: 1319-1342. doi: 10.1016/S0022-5096(98)00034-9
![]() |
[26] |
Friedrich M, Solombrino F (2018) Quasistatic crack growth in 2d-linearized elasticity. Ann Inst H Poincaré Anal Non Linéaire 35: 27-64. doi: 10.1016/j.anihpc.2017.03.002
![]() |
[27] |
Griffith AA (1921) The phenomena of rupture and flow in solids. Philos Trans R Soc London A 221: 163-198. doi: 10.1098/rsta.1921.0006
![]() |
[28] | Grisvard P (1985) Monographs and Studies in Mathematics, In: Elliptic Problems in Consmooth Domains, Boston: Pitman. |
[29] |
Khludnev AM, Shcherbakov VV (2018) A note on crack propagation paths inside elastic bodies. Appl Math Lett 79: 80-84. doi: 10.1016/j.aml.2017.11.023
![]() |
[30] |
Khludnev AM, Sokolowski J (2000) Griffith formulae for elasticity systems with unilateral conditions in domains with cracks. Eur J Mech A Solids 19: 105-119. doi: 10.1016/S0997-7538(00)00138-8
![]() |
[31] | Knees D (2011) A short survey on energy release rates, In: Dal Maso G, Larsen CJ, Ortner C, Mini-Workshop: Mathematical Models, Analysis, and Numerical Methods for Dynamic Fracture, Oberwolfach Reports, 8: 1216-1219. |
[32] |
Knees D, Mielke A (2008) Energy release rate for cracks in finite-strain elasticity. Math Method Appl Sci 31: 501-528. doi: 10.1002/mma.922
![]() |
[33] |
Knees D, Mielke A, Zanini C (2008) On the inviscid limit of a model for crack propagation. Math Mod Meth Appl Sci 18: 1529-1569. doi: 10.1142/S0218202508003121
![]() |
[34] |
Knees D, Rossi R, Zanini C (2013) A vanishing viscosity approach to a rate-independent damage model. Math Mod Meth Appl Sci 23: 565-616. doi: 10.1142/S021820251250056X
![]() |
[35] |
Knees D, Rossi R, Zanini C (2015) A quasilinear differential inclusion for viscous and rateindependent damage systems in non-smooth domains. Nonlinear Anal Real 24: 126-162. doi: 10.1016/j.nonrwa.2015.02.001
![]() |
[36] |
Knees D, Zanini C, Mielke A (2010) Crack growth in polyconvex materials. Physica D 239: 1470-1484. doi: 10.1016/j.physd.2009.02.008
![]() |
[37] | Krantz SG, Parks HR (2002) The Implicit Function Theorem: History, theory, and applications, Boston: Birkhäuser Boston Inc. |
[38] |
Lazzaroni G, Toader R (2011) A model for crack propagation based on viscous approximation. Math Mod Meth Appl Sci 21: 2019-2047. doi: 10.1142/S0218202511005647
![]() |
[39] |
Lazzaroni G, Toader R (2011) Energy release rate and stress intensity factor in antiplane elasticity. J Math Pure Appl 95: 565-584. doi: 10.1016/j.matpur.2011.01.001
![]() |
[40] | Lazzaroni G, Toader R (2013) Some remarks on the viscous approximation of crack growth. Discrete Contin Dyn Syst Ser S 6: 131-146. |
[41] |
Mielke A, Rossi R, Savaré G (2009) Modeling solutions with jumps for rate-independent systems on metric spaces. Discrete Contin Dyn Syst 25: 585-615. doi: 10.3934/dcds.2009.25.585
![]() |
[42] |
Mielke A, Rossi R, Savaré G (2012) BV solutions and viscosity approximations of rate-independent systems. ESAIM Control Optim Calc Var 18: 36-80. doi: 10.1051/cocv/2010054
![]() |
[43] |
Mielke A, Rossi R, Savaré G (2016) Balanced viscosity (BV) solutions to infinite-dimensional rate-independent systems. J Eur Math Soc 18: 2107-2165. doi: 10.4171/JEMS/639
![]() |
[44] | Mielke A, Roubíček T (2015) Rate-Independent Systems, New York: Springer. |
[45] |
Nazarov SA, Specovius-Neugebauer M, Steigemann M (2014) Crack propagation in anisotropic composite structures. Asymptot Anal 86: 123-153. doi: 10.3233/ASY-131187
![]() |
[46] |
Negri M (2011) Energy release rate along a kinked path. Math Method Appl Sci 34: 384-396. doi: 10.1002/mma.1362
![]() |
[47] |
Negri M (2014) Quasi-static rate-independent evolutions: Characterization, existence, approximation and application to fracture mechanics. ESAIM Control Optim Calc Var 20: 983-1008. doi: 10.1051/cocv/2014004
![]() |
[48] |
Negri M, Ortner C (2008) Quasi-static crack propagation by Griffith's criterion. Math Mod Meth Appl Sci 18: 1895-1925. doi: 10.1142/S0218202508003236
![]() |
[49] |
Negri M, Toader R (2015) Scaling in fracture mechanics by Bažant law: From finite to linearized elasticity. Math Mod Meth Appl Sci 25: 1389-1420. doi: 10.1142/S0218202515500360
![]() |
1. | Burkhan Kalimbetov, Valeriy Safonov, Dinara Zhaidakbayeva, Asymptotic Solution of a Singularly Perturbed Integro-Differential Equation with Exponential Inhomogeneity, 2023, 12, 2075-1680, 241, 10.3390/axioms12030241 | |
2. | Musabek AKYLBAYEV, Burhan KALİMBETOV, Nilufar PARDAEVA, Influence of rapidly oscillating inhomogeneities in the formation of additional boundary layers for singularly perturbed integro-differential systems, 2023, 2587-2648, 10.31197/atnaa.1264072 |