3
MODES OF FAILURE
Failure modes were deduced from observations of pho-
tographs and interviews with mechanics involved in the
repairs. The cracks in the false floor originated at the plate
edges and stich-welded connections radiating into the
unreinforced areas of the sheet which are highly character-
istic of stress reversals and metal fatigue. Yielding failures of
the intermediate wall between aqueous and organic sides
below the false floor were also reported as broken members
and metal deformations.
BASIS OF ANALYSIS
The analysis of the existing E1B mix box and the CAID
preliminary design was generated from information col-
lected at the site, including field observations, operator
interviews, real-time operational data, and field measure-
ments, original engineering drawings, and preliminary
drawings from CAID.
Considering first principles, balance of mass and
energy, balance of momentum and moment of momen-
tum, etc. led to the identification of the sources of the
forces that develop the ultimate static and dynamic loading
on the plate structure of the mix box which include the
flow dynamics of entering, internal, and exiting fluid flows,
and mixer dynamics.
Applications of Navier-Stokes as well as constitutive
equations of fluid and solid mechanics and general plate
theory were utilized to evaluate the hydrodynamics and
states of stress in the platework and reinforcing. Some sim-
plifying assumptions were made to enable the modeling of
the flows with fundamental equations of momentum, fluid
statics, and other constitutive equations.
ANALYSIS
E1B Feed Piping System Analysis
The lower flow conditions of PLS and Organic into the
E1B mix box, namely 7,650 gpm Aqueous and 3,700 gpm
Organic werae analyzed to determine the flow regime, and
whether unsteady or surging flow conditions exist. Each of
these were evaluated to understand the dynamic flow con-
ditions into the lower chamber of the E1B mix box. It was
found that neither system would operate in an unsteady
flow condition that could result in transmitted surge effects
from pipeline surging. In other words, pressure loads
should be fairly static over time at the pipe discharges into
the mix boxes.
Figure 3. CAID proposed mix box replacement design
MODES OF FAILURE
Failure modes were deduced from observations of pho-
tographs and interviews with mechanics involved in the
repairs. The cracks in the false floor originated at the plate
edges and stich-welded connections radiating into the
unreinforced areas of the sheet which are highly character-
istic of stress reversals and metal fatigue. Yielding failures of
the intermediate wall between aqueous and organic sides
below the false floor were also reported as broken members
and metal deformations.
BASIS OF ANALYSIS
The analysis of the existing E1B mix box and the CAID
preliminary design was generated from information col-
lected at the site, including field observations, operator
interviews, real-time operational data, and field measure-
ments, original engineering drawings, and preliminary
drawings from CAID.
Considering first principles, balance of mass and
energy, balance of momentum and moment of momen-
tum, etc. led to the identification of the sources of the
forces that develop the ultimate static and dynamic loading
on the plate structure of the mix box which include the
flow dynamics of entering, internal, and exiting fluid flows,
and mixer dynamics.
Applications of Navier-Stokes as well as constitutive
equations of fluid and solid mechanics and general plate
theory were utilized to evaluate the hydrodynamics and
states of stress in the platework and reinforcing. Some sim-
plifying assumptions were made to enable the modeling of
the flows with fundamental equations of momentum, fluid
statics, and other constitutive equations.
ANALYSIS
E1B Feed Piping System Analysis
The lower flow conditions of PLS and Organic into the
E1B mix box, namely 7,650 gpm Aqueous and 3,700 gpm
Organic werae analyzed to determine the flow regime, and
whether unsteady or surging flow conditions exist. Each of
these were evaluated to understand the dynamic flow con-
ditions into the lower chamber of the E1B mix box. It was
found that neither system would operate in an unsteady
flow condition that could result in transmitted surge effects
from pipeline surging. In other words, pressure loads
should be fairly static over time at the pipe discharges into
the mix boxes.
Figure 3. CAID proposed mix box replacement design