PSI - Issue 81

Olena Romashko-Maistruk et al. / Procedia Structural Integrity 81 (2026) 269–275

272

c d c с DIF 1, /  

1

.

(5)

d k k

 

6 1     s  

3 1 

is

The coefficient of dynamic strengthening of compressed concrete in the range of its strain rates proposed to be taken according to Romashko-Maistruk and Romashko (2024b) using the expression:

10

10

s

2 / ))/9) ((1 log(    

, / cu c ck d ck f DIF f DIF  

,

(6)

s

5 1 10    s

where s   - the maximum deformation rate of compressed concrete under the action of static (quasi-static) loads, ; cu DIF - the limiting value of the coefficient of dynamic strengthening of compressed concrete at the instantaneous strain rate of compressed concrete, limited by the value 3 1 10   s m   : s  

2





   

   

2

2

2 1

1

2 1

k

k

k

 





  

  

/

 ln( 1) k

DIF

f

f

.

(7)





 



, ck du ck









cu

2

2

k

k

k





At the same time, the elastic-plastic coefficient of compressed concrete under the action of dynamic loads should also functionally depend on its strain rate. Such a dependence was obtained Romashko-Maistruk and Romashko (2024a) using methods of numerical analysis of expressions (5) and (6) using the law of conservation of specific potential energy of materials deformation: 2 / )/18) / )) (log( / )/9) /5 (9 log( 1 ( 1) (log(             m m m d k k k         , (8) where m   is the deformation rate of compressed concrete under the action of instantaneous dynamic loading, limited by the value 3 1 10   s m   . The range of changes in the elastic-plastic coefficient of compressed concrete for its various classes and deformation rates under the action of dynamic loads is shown in Fig. 2.

6.00

5.00

4.00

2.00 concrete (k d ) 3.00

1.00

0.00 Elastic-plastic coefficient of compressed

0

20

40

60

80

100

120

140

Concrete class (f ck,cube , MPa)

Fig. 2. The range of changes in the elastic-plastic coefficient of compressed concrete under dynamic loads for its different classes at strain rates: - 6 1 10    s   ; - 1 1 10    s   ; - 1 1 10   s   ; - 3 1 10   s   . The combination of dependencies (5), (6) and (8) allows one to quite easily predict the deformability of compressed concrete under the action of dynamic loads: DIF k k c d d c с / 1 1,      . (9) The range of changes in the level of deformability of compressed concrete for its various classes and deformation rates under the action of dynamic loads is shown in Fig. 3.